Subject: 1996 Abstracts Book
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ABSTRACTS
HSRC/WERC Joint Conference on the
Environment 1996

Program One Tuesday, May 21, 1996 Metals · Tampico Room

REMEDIATION OF LEAD
CONTAMINATED SOIL WITH EDTA: BATCH AND COLUMN STUDIES

CHELATING
EXTRACTION AND RECOVERY OF HEAVY METALS FOR REMEDIATION OF CONTAMINATED SOIL

DEVELOPMENT OF
NOVEL AND COST EFFECTIVE POLYMERIC CHELATORS FOR APPLICATIONS IN RADIOACTIVE
ACTINIDE WASTE REMEDIATION

BIOSORPTION OF
CADMIUM, CHROMIUM, LEAD, AND ZINC BY BIOMASS OF MEDICAGO SATIVA (ALFALFA)

HEAVY METAL
SPECIATION AND UPTAKE IN CRAYFISH AND TADPOLES

SPECIATION STUDIES
AND TOXICITY ASSESSMENT OF COMPLEX HEAVY METAL MIXTURES

BIOREMEDIATION IN
THE GEL BARRIER USING IMMOBILIZED YEAST FOR HEAVY METAL REMOVAL

UPTAKE OF METAL
IONS FROM SOLUTION BY INACTIVATED CELLS OF SYNECHOCOCCUS PCC 7942
(CYANOBACTERIA)

MICROBIAL REDUCTION
OF URANIUM USING CELLULOSIC SUBSTRATES

REMOVAL AND
RECOVERY OF COPPER AND CADMIUM BY AEROBIC MICROBIAL CULTURES GROWN WITH
BIOPOLYMER STIMULATORS

Program One Wednesday, May 22, 1996 Metals · Tampico Room

BIOREDUCTION OF
HEXAVALENT CHROMIUM IN BATCH CULTURES USING INDIGENOUS SOIL MICROORGANISMS

MOBILE CHROMATE TO
IMMOBILE PRECIPITATE-SUBSURFACE REACTIVE WALL SCENARIOS

REMEDIATION OF
CHROMATE-CONTAMINATED GROUND WATER USING ZERO-VALENT IRON: FIELD TEST AT USCG
SUPPORT CENTER, ELIZABETH CITY, NORTH CAROLINA

CALCIUM AND
MAGNESIUM INTERFERENCE STUDIES FOR THE BINDING OF HEAVY METAL IONS IN SOLUTION
BY MEDICAGO SATIVA (ALFALFA)

THE EFFECT OF
VEGETATION ON THE TRANSPORT OF HEAVY METAL IN A CONTAMINATED SOIL: A COLUMN
STUDY

APPLICATIONS OF
PERMEABLE BARRIER TECHNOLOGY TO GROUND WATER CONTAMINATION AT THE SHIPROCK, NM,
UMTRA SITE

AN ELECTROCHEMICAL
APPROACH FOR INVESTIGATING CORROSION OF SMALL ARMS MUNITIONS IN FIRING RANGES

THE TRANSPORT OF
ZINC IN SOIL AS AFFECTED BY CITRATE

A COMPUTER MODEL
FOR REMOVAL OF LEAD FROM CONTAMINATED SOILS

ON CONDUCTIVITY OF
SOILS WITH PREFERENTIAL FLOW PATHS

MODELING HEAVY
METAL MOVEMENT IN A ROOTED SOIL

EFFECT OF
VEGETATION ON CONTAMINANT TRANSPORT IN SURFACE FLOWS

UNSATURATED POROUS
MEDIA FLOWS ABOUT NON-PARTICIPATING FRACTURES

Program One Thursday, May 23, 1996 Munitions-Contaminated Soil · Tampico Room

TNT BREAKTHROUGH
CURVES FOR AQUIFER MATERIALS FROM THE LOUISIANA ARMY AMMUNITION PLANT,
SHREVEPORT, LA

PEROXONE TREATMENT
OF EXPLOSIVES-CONTAMINATED GROUND WATERS

FEDERAL INTEGRATED
BIOTREATMENT RESEARCH CONSORTIUM: FLASK TO FIELD

SCREENING FOR
REMOVAL OF TNT AND RDX BY SUBMERSED AND EMERGENT PLANT SPECIES FROM CONTAMINATED
GROUND WATER

BIOREMEDIATION OF
SOLID TNT PARTICLES IN A SOIL SLURRY REACTOR: MASS TRANSFER CONSIDERATIONS

PHYTOREMEDIATION
OF TNT-CONTAMINATED WATER: BENCH-TOP FLOW THROUGH REACTOR STUDIES

Program Two Tuesday, May 21, 1996 Chemical Technologies · Cozumel Room

CARBON
TETRACHLORIDE DECHLORINATION IN WATER USING BINARY METAL SYSTEMS

DECHLORINATION OF
TRICHLOROETHYLENE BY ZERO-VALENT METALS IN AQUEOUS ENVIRONMENTS

DECHLORINATION OF
CARBON TETRACHLORIDE WITH IRON: CARBON MASS BALANCE AND EFFECT OF OXYGEN ON
DECHLORINATION PATHWAYS

CHLOROFORM
TRANSFORMATION BY A METHANOGENIC CONSORTIUM UTILIZING ZERO-VALENT IRON AS
ULTIMATE ELECTRON DONOR

DESTRUCTIVE
ADSORPTION OF CHLOROCARBONS ON CALCIUM OXIDE

DESTRUCTIVE
ADSORPTION OF 2-CHLOROETHYL ETHYL SULFIDE BY MAGNESIUM OXIDE

EFFECT OF REDOX
ENVIRONMENT ON OXIDATION OF PENTACHLOROPHENOL WITH MANGANESE OXIDE

PHOTOCATALYTIC
DEHALOGENATION OF CHLORINATED COMPOUNDS WITH 2-PROPANOL AND ACETONE AS SOLVENTS

ACCELERATED
PHOTODEGRADATION OF AROMATIC COMPOUNDS WITH HYDROGEN PEROXIDE IN AN EMBEDDED
TITANIUM OXIDE REACTOR

DESTRUCTIVE
ADSORPTION OF ENVIRONMENTAL TOXINS UTILIZING CALCIUM OXIDE AND TRANSITION METAL
OXIDE-SUPPORTED CALCIUM OXIDE NANOPARTICLES

Program Two Wednesday, May 22, 1996 Chemical Technologies · Cozumel Room

USING FERRATE TO
REMOVE HYDRAZINES FROM WASTE WATER

REVIEW OF THE
GALVANIC STRIPPING PROCESS FOR USE IN TREATING OXIDIZED METAL WASTES

DEVELOPMENT OF
POLAROGRAPHIC FIELD SENSORS FOR HEAVY METAL DETECTION

Technology Transfer and Analytical Methods · Cozumel Room

IMPROVED
HYDROCARBON DETECTION

IDENTIFICATION OF
PENTACHLOROPHENOL IN ALLUVIAL SOILS UTILIZING IMMUNOASSAY FIELD METHODS, GRAND
TETON NATIONAL PARK, WYOMING-A CASE STUDY

POLLUTION
PREVENTION AND MICROSCALE CHEMISTRY IN THE RESEARCH LABORATORY

Technology Transfer and Munitions-Contaminated Soils · Cozumel Room

SOLIDIFICATION/STABILIZATION
OF METALS AND EXPLOSIVES IN SOIL

FIELD
DEMONSTRATION OF ON-SITE ANALYTICAL METHODS FOR TNT AND RDX IN GROUND WATER

FIRST
PRODUCTION-LEVEL BIOREMEDIATION OF EXPLOSIVES-CONTAMINATED SOIL IN THE U.S.

Technology Transfer and Field Applications · Cozumel Room

FIELD UP-SCALING
OF PROCESSES ASSOCIATED WITH BEHAVIOR OF NONAQUEOUS PHASE WASTE CHEMICALS IN
HETEROGENEOUS AQUIFERS

MINE RECLAMATION
AND RESIDUAL WASTES

GRAY DAUN URANIUM
MINE REMOVAL ACTION, SAN JUAN COUNTY, UTAH

ROLE OF
CARBONATION IN LONG TERM PERFORMANCE OF CEMENTITIOUS WASTEFORMS

Program Two Thursday, May 23, 1996 Technology Transfer and Field Applications
· Cozumel Room

MANAGING THE
PUMP-AND-TREAT END GAME

DESIGN
CONSIDERATIONS OF VERTICAL VERSUS HORIZONTAL WELL CONFIGURATIONS FOR AIR
SPARGING/SOIL VAPOR EXTRACTION REMEDIATION SYSTEMS

POLLUTION
PREVENTION ASSESSMENTS FOR MARINE MAINTENANCE AND CONTAINER PRINTING INDUSTRIES

Technology Transfer and Training · Cozumel Room

SUPERFUND
SCIENTISTS TEACH MINORITY HIGH SCHOOL STUDENTS SCIENTIFIC LITERACY AND CAREER
DEVELOPMENT IN NOVEL YEAR-ROUND PROGRAM TIED TO SUPERFUND INVESTIGATIONS

RAD WORLD/TV EARTH
ENVIRONMENTAL VIDEOS

NATIVE AMERICAN
ENVIRONMENTAL ISSUES: PUEBLO SUPERFUND PROGRAM

Program Three Tuesday, May 21, 1996 Organic Contaminants · Coronado Room

OPTIMIZATION OF
CONTAMINANT REMOVAL FOR HETEROGENEOUS SYSTEMS BY SOIL VENTING

REMOVAL OF
HYDROCARBONS FROM CONTAMINATED WATER USING AIR-SPARGED HYDROCYCLONE TECHNOLOGY

MATHEMATICAL
MODELS FOR BIODEGRADATION OF CHLORINATED SOLVENTS

SURFACTANT-ENHANCED
TRANSPORT OF HYDROPHOBIC ORGANIC COMPOUNDS

SOLVENT EXTRACTION
FOR REMEDIATION OF SOILS AT WOOD TREATMENT SITES

SURFACTANT-ENHANCED
DISSOLUTION OF NONAQUEOUS PHASE LIQUIDS IN SANDY AQUIFER MATERIALS-EFFECTS OF
DIMENSIONALITY AND SCALE

Barriers and Transport · Coronado Room

CONTAINMENT OF
HEAVY METAL AND CHLORINATED ORGANIC SOLVENT CONTAMINATION USING SUBSURFACE
BIOBARRIERS

BIOFILM BARRIERS
IN SOIL

THE EFFECT OF
ULTRA PURE WATER FLUSHING ON BACTERIAL TRANSPORT IN NATURAL SEDIMENTS

INCREASING THE
DIVERSION LENGTH OF CAPILLARY BARRIERS

Program Three Wednesday, May 22, 1996 Modeling and Transport · Coronado Room

STOCHASTIC
MODELING OF SOLUTE TRANSPORT IN A FRACTURED MEDIUM

MODELING FATE AND
TRANSPORT OF ATRAZINE IN THE SATURATED-UNSATURATED ZONE OF SOIL

FIELD VALIDATION
OF THE BACKWARD-IN-TIME ADVECTION DISPERSION THEORY

Nonaqueous Phase Liquids · Coronado Room

DIMENSIONALITY AND
HETEROGENEOUS EFFECTS ON ENHANCED LNAPL RECOVERY USING HOT WATER FLOODING

FATE AND TRANSPORT
OF RESIDUAL NAPLS UNDER FLUCTUATING WATER TABLE CONDITIONS

DNAPL MIGRATION IN
A COMPLEX MULTI-AQUIFER SYSTEM

Contaminant Fate and Transport · Coronado Room

BENCH-SCALE
INVESTIGATIONS ON VIBRATORY MOBILIZATION OF IMMISCIBLE LIQUID GANGLIA

THE BINDING OF
ORGANIC CONTAMINANTS TO HUMIN

CONTAMINATED SOIL
RECOVERY RATE OF A LEACHER COLLECTION SYSTEM

PCBs and Mohawk Nation Superfund Site · Coronado Room

AN OVERVIEW OF
SUPERFUND BASIC RESEARCH OF PCB POLLUTION OF THE MOHAWK NATION

PHOTOCATALYTIC
DEGRADATION OF PCBs IN AQUEOUS TiO2 SUSPENSIONS

SUPERCRITICAL
FLUID TECHNOLOGY FOR PCB/PAH-CONTAMINATED SOIL REMEDIATION

APPLICATION OF
REMEDIAL TECHNOLOGIES AT THE MOHAWK NATION SUPERFUND SITE

Program Three Thursday, May 23, 1996 Risk Assessment · Coronado Room

DEVELOPMENT &
IMPLEMENTATION OF A HIGH MOUNTAIN DESERT ECOLOGICAL RISK ASSESSMENT

ESTROGENIC AND
PROGESTAGENIC SCREENING OF POLLUTANTS IN VITRO USING ENDOMETRIAL AND
BREAST CANCER CELL LINES

UPTAKE OF
TRICHLOROETHYLENE BY EDIBLE GARDEN PLANTS

CREATION OF THE
ARMY'S BIOLOGICAL TECHNICAL ASSISTANCE GROUP: A HELP GROUP FOR ECOLOGICAL RISK
ASSESSMENTS

PERCEPTIONS OF
ENVIRONMENTAL RISK IN THREE COMMUNITIES OF EL PASO, TEXAS

ARSENIC RISK AND
REGULATION

Program Four Tuesday, May 21, 1996 Analytical Methods · Santa Fe Room

A SIMPLE
INEXPENSIVE ASSAY FOR TOXIC CHEMICALS USING A BACTERIUM AS THE INDICATOR
ORGANISM

FLUORESCENT SILICA
COLLOIDS FOR STUDYING CONTAMINANT TRANSPORT IN GROUND WATER

MATERIAL
CLASSIFICATION OF NONAQUEOUS PHASE LIQUID FROM 3D IMAGING DATA

DEVELOPMENT OF AN
INSTRUMENTAL FRACTIONATION AND QUANTITATION SCHEME FOR SELECTED POLYNUCLEAR
AROMATIC HYDROCARBONS PRESENT IN EXTRACTS FROM WOOD-PRESERVING WASTE

DEVELOPMENT OF AN
IN SITU INSTRUMENTATION BUNDLE FOR MONITORING AIR INJECTION REMEDIATION
TECHNOLOGIES

ELECTROCHEMICAL
SENSORS FOR REMOTE MONITORING OF INORGANIC AND ORGANIC CONTAMINANTS

INFRARED PYROMETRY
FOR WASTE CHARACTERIZATION

ATOMIC FORCE
MICROSCOPY (AFM) IMAGING OF DESTRUCTIVE ADSORBENT PARTICLE SURFACE MORPHOLOGY

USE OF X-RAY
ABSORPTION NEAR-EDGE STRUCTURE TO DETECT BIOLOGICAL REDUCTION OF CHROMIUM(VI)

USE OF TRACERS FOR
THE CHARACTERIZATION OF SCALE-DEPENDENT SUBSURFACE PROPERTIES: INITIAL
EVALUATION

Program Four Wednesday, May 22, 1996 Bioremediation · Santa Fe Room

FACTORS
INFLUENCING THE MICROBIAL METABOLISM OF PAH IN SOILS

AQUEOUS SYSTEM
REMEDIATION OF ORGANOHALIDE POLLUTANTS BY THE UTILIZATION OF AQUATIC ORGANISMS

BIOREMEDIATION
ENHANCEMENT BY PHYSICOCHEMICAL PRETREATMENT

EVALUATION OF
SULFUR-BASED AUTOTROPHIC DENITRIFICATION

TREATMENT OF
TRICHLOROETHENE (TCE) WITH A FLUIDIZED-BED BIOREACTOR

ANAEROBIC
BIODEGRADATION OF TOLUENE IN A PLUG-FLOW DIGESTER

RELATIONSHIP
BETWEEN AEROBIC BIODEGRADATION RATES, CHEMICAL STRUCTURE, AND SOIL TYPE FOR
SELECTED PETROLEUM HYDROCARBONS

INFLUENCE OF
MOISTURE CONTENT ON BIOREMEDIATION OF ORGANIC CONTAMINANTS IN THE SUBSOIL

BIOREMEDIATION
BACTERIA TO PROTECT PLANTS FROM PENTACHLOROPHENOL TOXICITY IN SOIL

Bioremediation and Volatile Compounds · Santa Fe Room

DESIGN OF CLOSED
CHAMBERS FOR MEASURING PHYTOREMEDIATION: OPTIMIZING PLANT GROWTH AND CHEMICAL
MASS BALANCE

EXPERIMENTAL AND
MODELING STUDIES OF THE FATE OF TRICHLOROETHYLENE IN A CHAMBER IN THE PRESENCE
OF ALFALFA PLANTS

THE EFFECT OF
SOIL WETTING AND DRYING PROCESSES ON THE TRANSPORT BEHAVIOR OF VOLATILE ORGANIC
COMPOUNDS IN UNSATURATED POROUS MEDIA

COMPARISON OF
FIELD AND LABORATORY METHODS FOR VOCS AND MAJOR GASES IN SOIL VAPOR

Program Four Thursday, May 23, 1996 Phytoremediation · Santa Fe Room

PHYTOREMEDIATION
AT HAZARDOUS WASTE SITES

REMEDIATION OF
PESTICIDE WASTES USING RHIZOSPHERE MICROORGANISMS

VARIATION IN ROOT
GROWTH AMONG FOUR SORGHUM VARIETIES GROWN IN SOIL CONTAMINATED WITH PETROLEUM
HYDROCARBONS

DETECTION OF
AGRONOMIC AND BIOREMEDIATION VARIABILITIES BETWEEN ALFALFA CLONES GROWN IN
CRUDE-OIL CONTAMINATED SOILS

USE OF BIOMARKERS
TO ASSESS PHYTOREMEDIATION OF PETROLEUM-CONTAMINATED SOILS

PHYTOREMEDIATION
OF PETROLEUM CONTAMINATED SOIL-A FIELD ASSESSMENT

Posters · Taos, Las Cruces, and Yucatan Rooms and Pre-Convention Area

INNOVATIVE
TECHNOLOGIES FOR THE REMEDIATION OF SOIL AND GROUND WATER FROM THE DEPARTMENT OF
ENERGY, OFFICE OF TECHNOLOGY SYSTEMS

HEAVY METAL
REMOVAL AND RECOVERY BY COMBINED PHYTOREMEDIATION AND ANAEROBIC FERMENTATION

DNAPL MIGRATION
THROUGH A MULTI-AQUIFER AND FRACTURED AQUITARD SYSTEM

ELECTROKINETIC
REMEDIATION OF SOIL CONTAMINATED WITH OILFIELD BRINE

WASTE WATER
TREATMENT USING FERRATE TO REMEDIATE AQUEOUS AZODYES

CONTAMINANT
MONITORING OF RODENTS AT A RADIOACTIVE WASTE BURIAL SITE, LOS ALAMOS NATIONAL
LABORATORY

CONTAMINANT
MONITORING OF BIOTA DOWNSTREAM OF A RADIOACTIVE LIQUID WASTE TREATMENT FACILITY,
LOS ALAMOS NATIONAL LABORATORY

DEVELOPMENT OF
POLYHYDROXAMATE CHELATORS FOR APPLICATIONS TO ACTINIDE REMEDIATION

DEVELOPMENT OF
TAILORED BIOFILTER FOR REMOVAL OF HEAVY METALS

CS-137
CONTAMINATION MEASUREMENTS OF TECHA RIVER BANK TERRITORY IN BRODOKALMAK
SETTLEMENT

GAMMA LOCATOR TO
DETERMINE SPECTRUM CHARACTERISTICS OF QUANTUM FLUX

ESTIMATION OF
GEOCHEMICAL BACKGROUND LEVELS FOR ENVIRONMENTAL STUDIES USING EXISTING DATA
SOURCES

ULTRASOUND-MODIFIED
CUPRIC ION ADSORPTION ON IRON (III) FLOCS

EVALUATING THE
BIOACCUMULATION OF HEAVY METALS AND ORGANICS IN AN AQUATIC ENVIRONMENT

IMMOBILIZATION OF
INDUSTRIAL WASTE IN CEMENT MATRIX

THE UPTAKE OF
STRONTIUM BY CHAMISA (CHRYSOTHAMNUS NAUSEOSUS) SHRUB PLANTS GROWING OVER
A FORMER LIQUID WASTE DISPOSAL SITE AT LOS ALAMOS NATIONAL LABORATORY

ENVIRONMENTAL
PROGRAM AT JACKSON STATE UNIVERSITY

MICROBIAL
POPULATION DYNAMICS AND BIODEGRADATION KINETICS OF ORGANIC POLLUTANT MIXTURES

ASSESSMENT OF
BRINE CONTAMINATION OF SURFACE WATERS AND SOIL USING ION-SELECTIVE ELECTRODES

CORRELATION OF
SURFACE WATER QUALITY AND OIL PRODUCTION IN THE TALLGRASS PRAIRIE PRESERVE

RDX AND HMX
SORPTION IN THIN DISK SOIL COLUMNS

PHYTOREMEDIATION
OF LEAD-CONTAMINATED SOILS BY NATIVE SPECKS AT AN ABANDONED MINE SITE IN UTAH

EFFECT OF POPLAR
RHIZOSPHERE ON MICROBIAL POPULATIONS THAT DEGRADE PRIORITY POLLUTANTS

TRACER TESTS FOR
EVALUATING AIR SPARGING AND IN-WELL AERATION TREATMENT SYSTEMS

LABORATORY
EVALUATION OF OXYGEN TRANSFER RATES AND TRANSFER EFFICIENCIES OF AIR SPARGING
AND IN-WELL AERATION

BIODEGRADATION OF
CHELATING AGENTS USED FOR METAL REMOVAL FROM CONTAMINATED SOILS

TREATMENT OF WOOD
PRESERVATIVE-CONTAMINATED SOILS AS AFFECTED BY ELECTRON ACCEPTOR ADDITION

A BATCH REACTOR
FOR CONTROL OF Eh, pH, AND TEMPERATURE OF SUBSURFACE AQUEOUS SYSTEMS

HEAVY METALS
REMOVAL FROM CONTAMINATED WATER SOLUTIONS

ASSESSMENT OF
NATURAL ATTENUATION OF HEXAVALENT CHROMIUM IN GROUND WATER: USCG SUPPORT CENTER,
ELIZABETH CITY, NORTH CAROLINA

CELLS ON FOAM AND
FIBER

BIOAVAILABILITY
AND RISK ASSESSMENT OF CONTAMINATED SOIL USING AQUEOUS AND SOLVENT EXTRACTION

SOIL SORPTION AND
PAH SOLUBILITY ENHANCEMENT USING SURFACTANTS

BIODEGRADATION OF
SEVERAL SOLUBILITY ENHANCES BY ACTIVATED SLUDGE AND AN ENRICHED CULTURE

AN EXPERIMENTAL
INVESTIGATION OF THE VOLATILIZATION OF BINARY NONAQUEOUS PHASE LIQUID MIXTURES
IN UNSATURATED POROUS MEDIA

IMPROVED RECOVERY
OF HEAVY METALS AND CHELATING AGENTS FOLLOWING EXTRACTION FROM CONTAMINATED SOIL

EXPERIMENTAL
OBSERVATION OF TETRACHLOROETHENE TRANSPORT BEHAVIOR IN AN UNSATURATED SAND
COLUMN

ADSORPTION OF
ORGANIC POLLUTANT MOLECULES TO MINERAL SURFACES

OPTIMIZING TNT
DESTRUCTION IN CONTAMINATED WATER AND SOIL BY FENTON OXIDATION

FENTON OXIDATION
OF TNT IN SOIL SLURRIES AS INFLUENCED BY TEMPERATURE, DISSOLVED ORGANIC MATTER,
AND CLAY MINERALS

SIMULATION OF
WASTE-GENERATING CHARACTERISTICS DURING START-UP OF A REACTOR NETWORK UNDER
NONISOTHERMAL CONDITIONS

CADMIUM, COPPER,
AND ZINC ACCUMULATION IN TRANSGENIC AND NON-TRANSGENIC TOBACCO PLANTS

IDENTIFYING
GROUND WATER THREATS FROM IMPROPERLY ABANDONED BOREHOLES

CONTAMINANTS
MINERALIZATION USING ACTIVATED CARBON-AOPs SYSTEM

KINETICS AND
MECHANISM OF DEGRADATION OF HAZARDOUS CONTAMINANTS USING OZONE AND HYDROGEN
PEROXIDE

METABOLISM OF TNT
ASSOCIATED WITH ROOTS OF HIGHER PLANTS

MEASURING
CONTAMINANT FLUX THROUGH PLANTS BY FOURIER TRANSFORM INFRARED (FT-IR)
SPECTROMETRY

EVALUATION OF
TOXICITY OF TRICHLOROETHYLENE FOR STERILE-GROWN PLANTS

MOBILIZATION AND
TRANSPORT OF DEPLETED URANIUM FROM SURFACE SYSTEMS

RESEARCH,
DEVELOPMENT, AND DEMONSTRATION (RD&D) PERMIT PROCESS FOR THE TREATMENT OF
RADIOACTIVE/HAZARDOUS WASTE

EFFECTS OF
FERTILIZATION RATES ON PHYTOREMEDIATION OF PETROLEUM-CONTAMINATED SOILS

AN ASSESSMENT OF
MICROBIAL CHANGES DURING PHYTOREMEDIATION

DETERMINATION OF
TOTAL PETROLEUM HYDROCARBONS IN CONTAMINATED SOIL

EFFECT OF PLANT
EXUDATES ON THE BIOREMEDIATION OF SYNTHETIC DIESEL FUEL

THE IMPACT OF
VEGETATION ON HEAVY METAL MOVEMENT

THE EFFECT OF
FLUCTUATING WATER LEVELS ON BIODEGRADATION OF NAPLS IN SOIL

BIODEGRADATION
KINETICS OF CARBON TETRACHLORIDE, PERCHLOROETHYLENE, AND 1,1,1-TRICHLOROETHANE
WHEN PRESENT IN MIXTURES

SEQUENTIAL
TRANSFORMATION OF CARBON TETRACHLORIDE, PERCHLOROETHYLENE, AND
1,1,1-TRICHLOROETHANE USING METHANOGENIC AND METHANOTROPHIC CONDITIONS

NICKEL UPTAKE BY
THE HYPERACCUMULATOR STREPTHANTHUS POLYGALOIDES GROWN ON SERPENTINE AND
CALCAREOUS SOILS

MINERALIZATION OF
PENTACHLOROPHENOL IN SOIL BY WHITE-ROT FUNGI IN THE PRESENCE OF SURFACTANTS

RELATIONSHIP
BETWEEN BIOLOGICAL AND CHEMICAL GROUND WATER DATA AT A URANIUM MILL TAILINGS
SITE

APPLICATION OF
BIOSENSORS BASED ON NATIVE FLUORESCENCE

STRATIFICATION OF
SOIL CHEMICAL PROPERTIES IN REVEGETATED CHAT

PHOTOCATALYTIC
REDUCTIVE DEHALOGENATION OF TRICHLOROETHYLENE AND CARBON TETRACHLORIDE USING
OPTICAL FIBERS COATED WITH TiO2-CoTSP

STRATEGIES FOR
CONDITIONING OF SPENT RADIATION SOURCES IN CUBA

THERMAL TREATMENT
OF INDUSTRIAL-PRODUCED ACIDIC METAL CHLORIDE HAZARDOUS WASTE

DNA BIOSENSOR FOR
MONITORING HYDRAZINE COMPOUNDS

ASSURING QUALITY
MODEL USAGE, EXPERIMENTAL VALIDATION, AND EXTRAPOLATION TO FIELD SITES

EXPERIMENTAL
VERIFICATION OF REVISED FIRAC

MODELING OF HEAVY
METAL TRANSPORT AND SOIL EROSION IN SURFACE RUNOFF

GAS-DRIVEN
HYDROFRACTURE AT WIPP

FAST NEUTRON
THERMALIZATION AND CAPTURE GAMMA-RAY GENERATION IN SOILS

INTERPRETATION OF
NEUTRON-CAPTURE GAMMA-RAY DATA TO DETERMINE SOIL CONTAMINANT PROFILES

METALS SOIL
POLLUTION AND VEGETATIVE REMEDIATION USING POPLAR TREES AT TWO HEAVY
METAL-CONTAMINATED SITES

CLEAN-UP
PROCEDURES FOR WASTE WATERS WHICH FLOW FROM REFINERIES AND OTHER CHEMICAL
COMPANIES

EFFECTS OF
PRESSURE VARIATION ON TRANSPORT OF VOLATILE NONAQUEOUS PHASE WASTE CHEMICAL
VAPOR IN HETEROGENEOUS FORMATIONS

SPREADING OF
DENSE NONAQUEOUS PHASE LIQUIDS IN RANDOMLY HETEROGENEOUS AQUIFERS: EXPERIMENTS
ON MULTIPLE REALIZATIONS

CHARACTERIZING
AQUIFER HETEROGENEITY USING HYDRAULIC AND TRACER TESTS: EXPERIMENTAL AND
COMPUTATIONAL STUDIES

REDUCTIVE
DECHLORINATION OF CARBON TETRACHLORIDE USING ZERO-VALENT METALLIC ELECTRODES

A COMBINED
PLASTICITY/DAMAGE MODEL FOR CREEP OF ROCK SALT

MECHANISMS
GOVERNING THE REMOVAL OF WASTE FROM A WASTE REPOSITORY CAUSED BY EXPLORATORY
DRILLING

ADAPTIVE CONTROL
OF CONSTRAINED ROBOTIC SYSTEMS FOR WASTE MANAGEMENT APPLICATIONS

ADSORPTION OF
COPPER IONS FROM SOLUTION BY HEAVY METAL STRESSED-LARREA TRIDENTATA
(CREOSOTE BUSH) BIOMASS

STRONG OXIDANTS
FOR ORGANIC WASTE DESTRUCTION FROM OXIDATION OF MANGANESE HYDROXIDE

NEW APPROACHES
FOR ELEMENTAL SPECIATION STUDIES

BIOLOGICAL AND
CHEMICAL NITRATE REMOVAL USING AUTOTROPHIC DENITRIFIERS AND ZERO-VALENT IRON

DETERMINATION OF
THE CONTENT OF HAZARDOUS HEAVY METALS IN LARREA TRIDENTATA (CREOSOTE
BUSH) FOUND NATURALLY GROWING IN CONTAMINATED SOILS

MODELING THE ROLE
OF MICROORGANISMS IN THE MOVEMENT OF LEAD IN UNSATURATED REGION

NATURAL
BIOVENTING REMEDIATION FROM TIDAL WAVE ACTION AT A FIELD SITE

CHARACTERIZATION
OF PARA AND META PCB-DECHLORINATING ANAEROBIC COMMUNITIES BY 16S
rRNA GENES

AIR-SPARGED
HYDROCYCLONE TECHNOLOGY FOR ENVIRONMENT APPLICATIONS

BIOLOGICAL
TREATMENT OF AIR STREAMS CONTAMINATED WITH ORGANIC VAPORS

ULTRASONIC
ENHANCEMENT FOR IN SITU REMEDIATION OF CONTAMINATED SOIL

NOVEL CHOLINE
ESTERASE-BASED SENSOR FOR MONITORING OF ORGANOPHOSPHORUS POLLUTANTS

POLYMER GEL AS A
BARRIER FOR GROUND OIL SPILL CONTAINMENT

DEVELOPING A
SITE-WIDE HAZARDOUS WASTE MINIMIZATION PROGRAM

NAVAJO
NATION-BASED, CROWNPOINT INSTITUTE OF TECHNOLOGY'S ENVIRONMENTAL TECHNOLOGY
PROGRAM

HERS: A CENTER
FOR RESEARCH, EDUCATION, AND COMMUNICATION

ENVIRONMENTAL
CONCERNS ON THE OSAGE RESERVATION

NAVAJO STUDENTS
MONITOR A LOCAL URANIUM-MILL TAILINGS SITE

MONITORING AND
MINIMIZING AIR POLLUTANTS FROM PAINTS USED AT TURTLE MOUNTAIN MANUFACTURING
COMPANY, BELCOURT, ND

AIR QUALITY AND
RESPIRATORY HEALTH OF SHIPROCK (NAVAJO NATION) RESIDENTS: PRELIMINARY STUDIES OF
METEOROLOGICAL AND HEALTH DATA

EARTH SYSTEMS
AND NAVAJO PEDAGOGY

DEVELOPMENT OF
ENVIRONMENTAL TECHNOLOGY CURRICULUM FOR NATIVE AMERICAN COLLEGES

COMMUNITY
WORKSHOPS IN NAVICULTURE, TRADITIONAL PLANNING, AGRICULTURE, AND COMMUNITY
ENVIRONMENTAL PLANNING WITHIN THE SHIPROCK AREA OF THE NAVAJO NATION

NAOMI SEMINAR
PROGRAM: EXPLORING NATIVE ENVIRONMENTAL ISSUES THROUGH VIDEO COMMUNICATION

EFFECT OF
PNEUMATIC FRACTURING ON AN EXISTING STRUCTURE

POTENTIAL
OPTIONS & MANUFACTURING CHANGES FOR ETHYL ETHER IN SUPPORT OF POLLUTION
PREVENTION

PNEUMATIC
FRACTURING COMPUTER MODEL

INVESTIGATION
INTO FRACTURE BEHAVIOR AND LONGEVITY OF PNEUMATICALLY-FRACTURED FINE-GRAINED
FORMATIONS

USE OF IN
SITU OZONATION FOR THE REMEDIATION OF CONTAMINATED SOILS

EFFECTS OF
LAKE/AQUIFER INTERACTIONS ON THE BIOTRANSFORMATION OF CHLORINATED SOLVENTS
DISCHARGING TO THE LAKE

EFFECT OF
ELECTRON DONOR AND ELECTRON ACCEPTOR CONCENTRATIONS ON REDUCTIVE DECHLORINATION
RATES OF TCE AT A SULFIDOGENIC GROUND WATER/SURFACE WATER INTERFACE

SORPTION OF
PHENANTHRENE BY NATURAL AND SYNTHETIC ORGANIC MATRICES

FOURIER
TRANSFORM INFRARED SPECTROSCOPIC AND ELLIPSOMETRIC STUDIES OF EXOPOLYSACCHARIDE
AND BIOFILM ATTACHMENT ON SILICA

PROPOSED STUDIES
IN SURFACTANT-ENHANCED BIOREMEDIATION OF ORGANIC CONTAMINANTS

FENTON OXIDATION
TO REMEDIATE RDX-CONTAMINATED WATER AND SOIL

OVERVIEW OF
KANSAS EPA EPSCoR PROJECTS

THE EFFECTS OF
THE RHIZOSPHERE ON THE OXIDATION STATE OF CHROMIUM IN SLUDGE-AMENDED SOILS

COMETABOLISM OF
TRICHLOROETHENE (TCE) IN FLUIDIZED-BED BIOREACTORS

MIXING AND
AGITATION IN SLURRY REACTORS FOR BIOREMEDIATION

THE INFLUENCE OF
PHOSPHORUS ON CHEMICAL AND MINERALOGICAL PROPERTIES OF A ZINC/LEAD SMELTER SLAG

COMPUTER
SIMULATION OF THE EFFECT OF VEGETATIVE REMEDIATION OF SOILS-PROPOSED WORK

SOIL FLUSHING OF
HEXACHLOROBENZENE USING SURFACTANT AND COLLOIDAL GAS APHRONS IN A
TWO-DIMENSIONAL SYSTEM

DETERMINING SOIL
CONTAMINANTS USING NEUTRON ACTIVATION AND GAMMA-RAY SPECTROSCOPY

CONSTRUCTION OF
CHLOROBIPHENYL DEGRADATION PATHWAY IN GRAM + BACTERIUM RHODOCOCCUS
ERTHREUS STRAIN NY05
SEARCH AUTHOR
AND KEYWORD INDEX

Program One
Tuesday, May 21, 1996
Metals · Tampico Room

1 • REMEDIATION OF LEAD CONTAMINATED SOIL WITH EDTA: BATCH AND
COLUMN STUDIES

D. Heil1, Z.A. Samani2, A. Hanson2, and S.
Hu2, 1Department of Agronomy and Horticulture, New Mexico
State University, Las Cruces, NM, 88003, and 2Civil, Agricultural,
and Geological Engineering Department, New Mexico State University, Las Cruces,
NM, 88003

Chelate extraction using ethylenediaminetetraacetic acid (EDTA) and other
chelates has been demonstrated to be an effective method of removal of Pb from
many contaminated soils. However, column leaching of Pb from alkaline soils with
EDTA has been problematic due to extremely low soil permeability. The purpose of
this study was to determine the effect of the addition of KOH and
Ca(Cl)2 to K2H2EDTA extraction solution on Pb
removal and hydraulic conductivity. A Pb-contaminated soil was sampled from an
abandoned lead-acid battery recycling facility. Both batch shaker extractions
and column leaching experiments were completed using 5 different EDTA extract
solutions. Addition of Ca(Cl)2 only to K2H2EDTA
did not change the amount of Pb removed by batch extraction. Lead solubility was
observed to decrease as pH was increased by the addition of KOH. The amount of
time required to leach 6.0 l of extraction solution through the soil columns
varied from 2 to 33 days. The addition of Ca(Cl)2 and/or KOH resulted
in increased soil hydraulic conductivity. However, Pb removal was diminished
with the addition of Ca(Cl)2 and KOH because of decreased Pb
solubility and also a shorter residence time of the extract solution in the
column. The hydraulic conductivity was related to residual calcium carbonate
content, suggesting that dissolution of CaCO3 and subsequent
production of CO2 gas in soil pores was partially responsible for the
observed reductions in soil permeability.

Key words: remediation, lead, soil, EDTA.

Oral presentation in metals session.

2 • CHELATING EXTRACTION AND RECOVERY OF HEAVY METALS FOR
REMEDIATION OF CONTAMINATED SOIL

A. Hong and W. Jiang, Department of Civil and Environmental Engineering,
University of Utah, Salt Lake City, UT, 84112

The remediation of heavy-metals-contaminated soils by chelating extraction is
of significant value to industrialized nations facing the problem that resulted
from economic activities including agriculture, mining, and mineral processing.
Although chelating agents have been tested and known to be capable of extracting
heavy metals from contaminated media, the difficulty in recovering the valuable
chelating agents for reuse has rendered the technology economically less
attractive. A major focus of this paper is on the recovery of chelating agents
for further reuse, thereby increasing the economical viability of this
technology. In this paper, results of extraction and recovery of heavy metals
from a contaminated soil using various chelating agents will be reported. The
results will demonstrate that: 1) many chelating agents are capable of removing
heavy metals including Pb, Cu, Cd, and Zn; 2) chelating agents and the extracted
heavy metals can be separately recovered; and 3) the recovered chelating agents
can be reused in subsequent extraction and recovery. The accumulative removal of
heavy metals in four consecutive runs amounted to 90% of the total heavy metals
in one contaminated soil.

Key words: heavy metal, soil remediation, chelating extraction, recovery.

Oral presentation in metals session.

3 • DEVELOPMENT OF NOVEL AND COST EFFECTIVE POLYMERIC
CHELATORS FOR APPLICATIONS IN RADIOACTIVE ACTINIDE WASTE REMEDIATION

A.S. Gopalan1, H. Jacobs1, P. Stark1, N.
Koshti1, G.D. Jarvinen2, B. Smith2, and T.
Robison2, 1Department of Chemistry and Biochemistry, New
Mexico State University, Las Cruces, NM, 88003, and 2Los Alamos
National Laboratory, Los Alamos, NM, 87545

A major goal of our research program is to develop polymer-supported,
ion-specific extraction systems for removing radioactive actinides and other
hazardous metal ions from wastewaters. This project is part of a broader effort
in our laboratory to develop novel and cost effective chelators that have the
high selectivity and binding constants needed to remove actinide ions such as
plutonium from soils and waste streams. Selected ligands from our ongoing
research efforts are being attached into polymeric backbones to create novel
chelating polymers. The resultant polymers can be either water soluble or water
insoluble depending on the polymeric matrix being used to anchor the ligands. A
number of water soluble chelating polymers have been synthesized in our
laboratory by functionalization of commercially available polyallylamine and
polyethyleneimine with various ligand moieties such as hydroxamates and
carboxylates. The ability of these polymers to complex with representative metal
ions to give soluble complexes under different pH conditions has been examined.
Both the synthesis of some chelating polymers and the results of their
preliminary evaluation will be presented.

Key words: chelating polymers, actinides, remediation, radioactive.

Oral presentation in metals session.

4 • BIOSORPTION OF CADMIUM, CHROMIUM, LEAD, AND ZINC BY
BIOMASS OF MEDICAGO SATIVA (ALFALFA)

J.L. Gardea-Torresdey, K.J. Tiemann, J.H. Gonzalez, and O. Rodriguez,
Department of Chemistry, The University of Texas at El Paso, El Paso, TX,
79968

Previous laboratory batch experiments of Medicago sativa (Alfalfa)
indicated that the African shoots population had a excellent ability to bind
copper(II) and nickel(II) ions from aqueous solution. Batch laboratory pH
profile, time dependency, and capacity experiments were performed to determine
the binding ability of the African shoots to cadmium(II), chromium(III),
chromium(VI), lead(II), and zinc(II). Batch pH profile experiments for the
mentioned ions indicated that the optimum pH for metal binding is approximately
5.0. Time dependency experiments for the metal ions showed that for all the
metals studied, binding to the African alfalfa shoots occurred within 5 minutes.
Binding capacity experiments revealed the following amounts of metal ions bound
per gram of biomass: 7.1 mg Cd, 8.7 mg Cr(III), 43 mg Pb(II), and 4.7 mg Zn(II).
However, no binding occurred for chromium(VI). Nearly all of the metals studied
were recovered by treatment with 0.1 M HCl, with the exception of chromium(III).
Column experiments were performed to study the binding of Cd(II), Cr(III),
Cr(VI), Pb(II) and Zn(II) to silica-immobilized African alfalfa shoots under
flow conditions. These experiments showed that the silica-immobilized African
alfalfa shoots were effective for removing metal ions from solution, and over
90% of the bound Pb(II), Cu(II), Ni(II), and Zn(II), and over 70% Cd(II), were
recovered after treatment with 4 bed volumes of 0.1 M HCl. The results from
these studies will be useful for a novel phytoremediation technology to remove
and recover heavy metal ions from aqueous solution.

Key words: phytoremediation, alfalfa, Medicago sativa, heavy metal
binding.

Oral presentation in metals session.

5 • HEAVY METAL SPECIATION AND UPTAKE IN CRAYFISH AND
TADPOLES

K. Bundy, D. Berzins, L. Millet, and P. Taverna, Department of Biomedical
Engineering, Tulane University, New Orleans, LA, 70118

Heavy metal pollution can have direct influence upon the biota in fragile
wetland ecosystems. Different species may be differentially impacted depending
upon their feeding habits, how they metabolize toxic chemical forms, and which
organs are most active in metal sequestration. The studies performed here are
laboratory investigations aimed at examining the uptake and bioaccumulation of
chromium and lead by crayfish and tadpoles. The chromium uptake studies involved
exposing red swamp crayfish (Procambarus clarkii), a bottom feeder and an animal
of commercial importance in Louisiana, to Cr+6 in the form of
dissolved potassium dichromate for periods of 4 and 7 weeks at 0.3, 3.0, and 30
mg/l concentrations. Control crayfish (0 mg/l) were exposed to tap water for the
same periods of time. After the exposure times were reached, hepatopancreas,
gill, and abdominal muscle tissue samples were collected from the crayfish. Each
tissue was examined for its content of the more toxic Cr+6 and less
toxic Cr+3 forms. Extraction methods tailored specifically for each
tissue were developed that provided good recovery of the metal with minimal
valence state conversion. Analysis for total chromium content in tissue was done
using atomic adsorption spectroscopy (AAS). The Cr+6 content was
measured using differential pulse polarography (DPP). Polarography is an
electrochemical method in which reduction occurs upon an electrode, causing a
current that is proportional to the concentration of the substance being
reduced. The potential at which the current is maximized (the half wave
potential) is unique for each oxidation state of each metal. Trivalent chromium
levels were derived by the difference between total chromium and hexavalent
chromium levels. The data showed chat total chromium concentration in gill
tissue increases with both exposure period and concentration level reaching a
maximum of 50 ppm for the 30 ppm 7 week exposure. Although total chromium
concentration rose, Cr+6 concentrations in gill tissue were found to
remain relatively constant at about 1.5-3.0 ppm, independent of exposure period
and concentration. The data suggest there must exist a physiological mechanism
in the gills to reduce hexavalent chromium to the less dangerous trivalent form
when its concentration reaches a certain level. The second series of
bioaccumulation studies exposed tadpoles (Xenopus laevis), which are
filter feeders, to water and sediment containing concentrations of lead
comparable to those found at certain sites in Devil's Swamp, near Baton Rouge,
LA. Known sediment concentrations of lead were prepared utilizing sorption curve
measurements for lead onto kaolin clay. A linear relationship between sediment
and soaking solution concentration was observed. Tadpoles were exposed to levels
of 1X, 5X, and 10X multiples of actual Pb+2 values found in Devil's
swamp water and sediment. Exposure times of 3, 5, and 6 weeks were used. The
concentrations of lead in the tadpoles were ascertained using differential pulse
polarography (DPP). The data showed that there was substantial lead uptake with
definite biological effects. The total lead uptake was 0.84, 3.04, and 4.25 ppm
for control, 5X, and 10X concentrations, respectively, at 5 weeks. Body weights
were reduced by 28%, and 45% for 5X and 10X concentrations, respectively, at 5
weeks compared to controls. Developmental retardation was also observed: The
controls at 5 weeks were at development stages 60-64, while the 10X group was
only in the 51-54 range. Uptake and bioaccumulation of lead was seen to increase
with exposure time. For example, at the 5X exposure level the lead contents at
3, 5, and 6 weeks were 1.56, 3.04, and 3.83 ppm, respectively. In conclusion,
these two studies have developed methodology for examining the consequences of
chromium and lead pollution of crayfish and tadpoles, based on actual conditions
found in polluted areas. Polarographic speciation studies can give further
insight into how heavy metals are bioaccumulated and metabolized. It is
important to examine the effects of heavy metals in order to better understand
the complex ecology that exists in local Louisiana wetlands, as well as
globally, as it is impacted by pollution.

Key words: polarography, bioaccumulation, metal, crayfish, tadpoles.

Oral presentation in metals session.

6 • SPECIATION STUDIES AND TOXICITY ASSESSMENT OF COMPLEX
HEAVY METAL MIXTURES

K. Bundy and F. Mowat, Department of Biomedical Engineering, Tulane
University, New Orleans, LA, 70118

Mixtures of hazardous pollutant substances present difficult environmental
problems. There are several important broad issues to consider in this regard,
primarily involving identification of the chemical species present and
assessment of the potential toxicity of the mixtures themselves. These issues
are in fact highly linked in that different chemical forms may substantially
vary in toxicity. For example, trivalent chromium has a low order of toxicity,
while hexavalent chromium is highly toxic. Therefore, speciation studies may be
required to understand the potential hazards associated with the mixture. In
addition, the toxicity of pollutants in a mixture may be more than additive,
since synergistic interactions between two components in a mixture may make the
mixture more toxic than predicted by summing the effects of each individual
toxicant. In this research project, the complex mixture problem is being
attacked using a combination of toxicity assays and electrochemical methods.
Bioluminescent bacterial assays have been successfully used previously in
determining the toxicity of aquatic samples, sediments, and soils. The bioassay
is based on the reduction of light emitted by a nonpathogenic strain of bacteria
upon exposure to a toxic sample. In this investigation, the MicrotoxR
system is being used to gauge the hazards of components in heavy metal mixtures
using the light-emitting marine bacterium Vibrio fischeri. By sensing
changes in light output due to the presence of various concentrations of
toxicants, EC50 levels can be obtained. Instrumentation consists of a Microbics
500 Toxicity Analyzer integrated with an IBM PC PS2/Model 55 and associated
MicrotoxR Data Capture and Reporting Program Version 7.82 software.
The MicrotoxR bioassay is being used in conjunction with
polarographic techniques to identify specific oxidation states of heavy metals.
In the polarographic method, the potential of a mercury drop substrate is
changed, and the substance of interest is electrochemically reduced at the
substrate surface. The magnitude of the reduction current is proportional to the
reactant's concentration, and the potential at which the reduction occurs
uniquely identifies the substance responsible for the current. The solution in
which this process occurs is termed the supporting electrolyte. Polarographic
techniques are being used in this investigation to measure Pb(II), Cr(III),
Cr(VI), Cu(II), Cd(II), and As(V) concentrations in water and sediments. In
addition, this methodology (which usually is not used in a multi-element mode)
has been extended to mixtures of toxic heavy metals, namely solutions containing
Pb(II) and Cd(II), using a single supporting electrolyte technique that allows
for simultaneous measurement of multiple ions. The toxicity of various solutions
containing controlled amounts of heavy metal pollutants (Pb(II), Cr(VI),
Cr(III), and Cd(II)) has been measured using the MicrotoxR Chronic
Test System assay. Of the solutions tested, lead was found to be the most toxic
with an EC50 value of 1.02 mg/l after a 5 minute exposure. For the case of
chromium, the hexavalent was more toxic than the trivalent form with an EC50
approximately three orders of magnitude lower. Cadmium displayed an EC50 value
of 7.9 mg/l after a 5 minute exposure indicating a lesser toxicity hazard than
lead but significantly more than that of chromium. Mixtures of various ions are
being tested to determine if the toxicity of the mixture is predictable from
that of the individual components, and to observe whether synergistic or
antagonistic reactions occur. Using sorption curve measurements on a model clay
(kaolin), these studies are being extended to test the toxicity of Pb(II)-,
Cr(III)-, Cr(VI)-, Cu(Il)-, and As(V)-laden sediments. This research project
encompasses an intensive effort to develop methods and technologies that will
help to understand the chemistry and toxicity of water, sediments, and soils
contaminated by mixed wastes. The ultimate goal of the project is to evaluate
the performance of the combination polarographic and MicrotoxR assay
method and to ascertain their capability for use under field conditions.

Key words: MicrotoxR, metal mixtures, speciation,
polarography.

Oral presentation in metals session.

7 • BIOREMEDIATION IN THE GEL BARRIER USING IMMOBILIZED YEAST
FOR HEAVY METAL REMOVAL

E. Wilkins, Department of Chemical Engineering, University of New Mexico,
Albuquerque, NM, 87106

Cu2+, Cd2+, and Zn2+ (all as sulfates) were
used as artificial pollutant heavy metal ions to study the biosorption capacity
of Saccharomyces cerevisiae yeast. The immobilized yeasts (native yeast
or caustic-treated yeast) could be reactivated and reused in a manner similar to
ion exchange resins. No metal biosorption capacity decrease or biomass loss were
found after seven cycles. Yeast biomass immobilized in the alginate gel reduced
the quantity of heavy metal binding to the biomass, as compared to biosorption
by native yeast, by about 10-25%. However, yeast treated with hot alkali
enhanced its heavy metal biosorption capacity significantly. Base soluble
biomass which may also have metal binding capacity was reconstituted by adding
acid to adjust the pH to neutral. The effects of equilibrium concentration on
the biosorption capacity could be described by the Langmuir and Freundlich
adsorption isotherms. Both isotherms fitted all the experimental data well
except the Langmuir isotherm for Zn2+. For the Freundlich isotherm,
it was found to be preferable to use two different sets of model parameters for
different concentration regions, rather than to use one set of parameters only.
The concentration change point is around 1x10-4 M (10, 4, and 6 mg/l
for Cd2+, Cu2+, and Zn2+, respectively). The
biosorption preference series is in the order of Cu2+ >
Cd2+ > Zn2+. The heavy metal biosorption on the
immobilized caustic-treated yeast was temperature independent at lower initial
metal concentration, although the biosorption rate could be affected by
temperature. The initial pH of the heavy metal solution affected the metal
removal efficiency significantly owing to cation competition with the hydronium
ion. Cu2+, Cd2+, and Zn2+ biosorption by
immobilized caustic-treated yeast did not occur below pH 3, but increased
rapidly above pH 3, and leveled off at pH 4. The biosorption capacity almost
remained constant over rather wide pH range. Incorporation of the yeast inside
or on the top of the gel barrier would not only enhance the barrier capability
of retarding pollutant migrations, but also adding a bioremediation potential to
these migrating substances.

Key words: bioremediation, yeast, heavy metal, gel barrier.

Oral presentation in metals session.

8 • UPTAKE OF METAL IONS FROM SOLUTION BY INACTIVATED CELLS OF
SYNECHOCOCCUS PCC 7942 (CYANOBACTERIA)

J.L. Gardea-Torresdey1, J.L. Arenas2, R.
Webb2, K.J. Tiemann1, and J.H. Gonzalez1,
1Department of Chemistry and 2Department of Biological
Sciences, University of Texas at El Paso, El Paso, TX, 79968

Synechococcus PCC 7942 has the ability to grow under certain stressed
conditions that would kill most other bacteria. Solutions of 0.05 mM, 0.1 mM,
and 0.25 mM Cu2+ have been inoculated with synechococcus with
the idea that this cyanobacteria may develop certain defense mechanisms allowing
its survival in such stressed environments. Synechococcus also has the
ability to grow in mass quantity under ideal conditions, providing usable
biomass at a minimal effort. Using lyophilized biomass grown under normal
conditions, synechococcus was tested for its potential to bind copper,
lead, and nickel ions from solution. Batch experiments were performed to
determine the optimum binding pH, time dependency, and metal binding capacities
for copper(II), lead(II), and nickel(II), along with desorption of the metal
bound. The biomass studied showed a high affinity for all metal ions as the pH
increased from 2 to 6 with optimum binding occurring at pH 5. Time dependency
studies showed that this cyanobacteria had rapid binding to all three metals.
Capacity experiments showed that this cyanobacteria bound 11.3 mg of copper(II)
per gram of biomass, 30.4 mg of lead(II) per gram of biomass, and 3.2 mg of
nickel(II) per gram of biomass. More than 90% of copper(II), lead(II), and
nickel(II) metal ions were recovered when treated with 0.1 M HCl. Future studies
will be performed in order to determine whether metal ion binding occurs on the
cell wall surface or if the biomass is internally binding the metal ions.
Synechococcus can eventually be used as the source for a novel approach
in using biosystems to remediate contaminants from solution and making those
contaminants available to industry through an environmentally friendly
biofiltration system.

Key words: Synechococcus, cyanobacteria, heavy metal binding, bioremediation,
metal recovery.

Oral presentation in metals session.

9 • MICROBIAL REDUCTION OF URANIUM USING CELLULOSIC
SUBSTRATES

M. Thombre1, B.M. Thomson1, and L.L.
Barton2, 1Department of Civil Engineering, University of
New Mexico, Albuquerque, NM, 87131, and 2Department of Biology,
University of New Mexico, Albuquerque, NM, 87131

Previous work at the University of New Mexico and elsewhere has shown that
sulfate-reducing bacteria are capable of reducing uranium from the VI oxidation
state to the IV oxidation state (referred to in this paper as U(VI) and U(IV)).
The principal significance is that while U(VI) species are soluble, U(IV) is
quite insoluble. Uranium(VI) generally forms a pH-dependent suite of
uranyl-carbonate complexes, UO2CO3º,
UO2(CO3)22-, and
UO2(CO3)34- in ground water
solutions which, due to their non-ionic or anionic nature, are relative mobile
in most soils. In contrast, U(IV) will precipitate from solution as uraninite
(UO2(s)), coffinite (USiO4(s)), or similar mineral phases.
This chemistry forms the basis of a proposed ground water remediation strategy
in which microbial reduction would be used to remove uranium from solution. One
such system would consist of a permeable barrier constructed in which ground
water would flow through a zone of sulfate and nitrate reducing bacteria to
achieve uranium precipitation from solution. Most U(VI) reduction work to date
has focused on pure cultures of sulfate-reducing bacteria using low molecular
weight organic acids as the substrate. These substrates are not practical for an
actual application due to their high cost and the fact that they would be
quickly degraded, thus providing a very short usable life for a remediation
process. Furthermore, pure culture systems are virtually never suitable for
field scale application due to the impossibility of preventing contamination and
growth by other microbial species. This project investigated the ability of
mixed microbial populations, grown on a variety of cellulosic substrates, to
provide nitrate, sulfate, and, ultimately, U(VI) reduction. Initial experiments
were conducted in batch systems using a microbial consortia collected from
ground water at the Shiprock Uranium Mill Tailings Remedial Action (UMTRA)
project site. Five different substrates were used: non-crystalline cellulose,
alfalfa hay, wheat straw, sawdust, and soluble starch. A modified minimal salts
solution was used as a growth medium. Sodium bicarbonate was incorporated as a
buffer in place of phosphate to prevent U(VI)-phosphate precipitation. The
chemical composition of each microcosm was followed with time. Precipitates from
each system was collected and the precipitated U(IV) was determined to be
UO2(s). The batch studies were followed by a series of column studies
in which alfalfa hay, wheat straw, and sawdust were mixed with coarse sand to
simulate a permeable barrier. The feed solution had a chemical composition
similar to that of ground water at the Shiprock site. The initial hydraulic
residence time in each column was 1 day. Although good nitrate reduction was
found, little sulfate and U(VI) reduction was measured. The hydraulic residence
time was increased to 3 days after which good removal of both sulfate and
soluble U(VI) was found. At the conclusion of the column studies, solids were
collected from each and subjected to mineralogical analysis. UO2(s)
was the dominant form of uranium, consistent with the batch findings. The
theoretical and practical implications of this study will be presented. The
results support the proposed concept of a permeable barrier which relies upon
mixed culture microbial reduction of nitrate, sulfate, and U(VI) to achieve
remediation of contaminated ground water.

Key words: sulfate reduction, uranium reduction, permeable barriers.

Oral presentation in metals session.

10 • REMOVAL AND RECOVERY OF COPPER AND CADMIUM BY AEROBIC
MICROBIAL CULTURES GROWN WITH BIOPOLYMER STIMULATORS

K. Fukushi and S. Ghosh, Civil & Environmental Engineering Department,
The University of Utah, Salt Lake City, UT, 84112

Removal of copper and cadmium and their recovery by aerobic cultures were
studied using control and test stock cultures developed in chemostat reactors.
The control culture was grown on a glucose-mineral salts basal medium. Test
cultures were grown on the basal medium that also included selected biochemicals
to stimulate the synthesis of metal-removing biopolymers. Peptone, cysteine, and
beta-glycerophosphate were selected to serve as precursors of metal-complexing
biopolymers. These biochemicals were expected to enhance the production of the
extracellular biopolymers with high concentrations of anionic sites. Copper and
cadmium uptake kinetics were evaluated by exposing samples of control and test
stock cultures to copper and cadmium solutions in batch reactors at an initial
metal concentration of about 50 mg/l. A modified second-order metal uptake
kinetic model incorporating a metal-biopolymer dissociation function was
employed to predict the observed metal-uptake rates. The proposed kinetic model
fit well to experimental data. Test cultures developed on biopolymer stimulators
exhibited 10% to 140% higher metal uptake rates than that of the control
culture. Copper and cadmium sequestered by polymeric entities were recovered
with acid or sodium bicarbonate solution. Sodium bicarbonate solution recovered
heavy metal at a reasonably high recovery efficiency (87-92%) without affecting
cell viability.

Key words: copper, cadmium, biouptake, kinetics, recovery.

Oral presentation in metals session.

Program One
Wednesday, May 22, 1996
Metals · Tampico Room

11 • BIOREDUCTION OF HEXAVALENT CHROMIUM IN BATCH CULTURES
USING INDIGENOUS SOIL MICROORGANISMS

J.L. Bader1, G. Gonzalez1, P.C. Goodell1,
S.D. Pillai2, and A.S. Ali2, 1Department of
Geological Sciences, University of Texas at El Paso, El Paso, TX, 79968, and
2Texas A&M University Research Center, Research and Extension
Center, 1380 A&M Circle, El Paso, TX, 79927

Chromium exists in the environment in two oxidation states, +3 and +6, which
have very different chemical and physical properties. Hexavalent chromium exists
as the chromate anion and is much more mobile and toxic than Cr(III). Biological
methods for Cr reduction would be potentially less expensive than the chemical
methods currently used. Soil samples collected from a Superfund Site containing
26,000 mg kg-1 total Cr were used in batch culture studies to
determine if the indigenous microbial populations were capable of mediating the
reduction of Cr(VI) to Cr(III). Cr(VI) concentrations in the soil solutions were
reduced 35% (from 2,000 to 1,300 mg kg-1) under long term enrichment
conditions. Fungal populations capable of aerobic Cr(VI) reduction (from 2,000
to 1,600 mg l-1) were isolated. When soils that were not heavily
contaminated with Cr(VI) were used in batch cultures containing 1,000 mg
l-1 Cr(VI), concentrations were reduced by as much as 22% within 7
days. This data suggests that the genetic potential for chromate reduction may
be present in soil microorganisms irrespective of whether they have any previous
history of Cr(VI) exposure.

Key words: chromate, hexavalent chromium, bioreduction, bioremediation,
Superfund.

Oral presentation in metals session.

12 • MOBILE CHROMATE TO IMMOBILE PRECIPITATE-SUBSURFACE
REACTIVE WALL SCENARIOS

R.M. Powell1 and R.W. Puls2, 1ManTech
Environmental Research Services Corporation, R.S. Kerr Laboratory, P.O. Box
1198, Ada, OK, 74821-1198, and 2National Risk Management Research
Laboratory, USEPA, P.O. Box 1198, Ada, OK, 74821-1198

Chromate (CrO42-) is a toxic, carcinogenic, and highly
mobile anionic contaminant that is found in many subsurface systems. It is not
strongly adsorbed but is relatively easily reduced from Cr6+ to
Cr3+. When reduced, the chromium becomes much less toxic and its
mobility is diminished or eliminated by increased adsorption and the formation
of hydroxide precipitates. Some aquifers have natural reduction capacity that is
sufficient to lower the total chromate concentration, but this capacity may or
may not be sufficient to protect sensitive receptors downgradient. Recently it
has been shown that chromate can be reduced in the presence of metallic (i.e.
zero-valence-state) iron. This results in a chromium-iron hydroxide solid
solution, yielding extremely low Cr activity at the solid/aqueous interface. It
has also been demonstrated that chlorinated hydrocarbons can undergo reductive
dechlorination on iron surfaces. Iron-containing permeable reactive subsurface
barriers have been proposed for intercepting and remediating plumes of both
types. Iron is a relatively inexpensive and readily available element, making it
a nearly ideal candidate for installation in such walls. There is also data,
however, that indicates significant differences in the reactivities of various
purities and formulations of iron, as well as the effects of the geochemical
milieu on overall system reactivity. Numerous experiments have been performed
evaluating chromate reduction by various iron forms and other metals under
differing geochemical environments.

Key words: zero-valent iron, chromate, ground water remediation,
geochemistry, subsurface reactive barriers.

Oral presentation in metals session.

13 • REMEDIATION OF CHROMATE-CONTAMINATED GROUND WATER USING
ZERO-VALENT IRON: FIELD TEST AT USCG SUPPORT CENTER, ELIZABETH CITY, NORTH
CAROLINA

R.W. Puls1, C.J. Paul1, and R.M. Powell2,
1National Risk Management Research Laboratory, USEPA, P.O. Box 1198,
Ada, OK, 74820, and 2ManTech Environmental Research Services
Corporation, P.O. Box 1198, Ada, OK, 74820

A field test was conducted near an old hard-chrome plating facility on the
USCG Support Center near Elizabeth City, North Carolina, to evaluate the in
situ remediation of ground water contaminated by hexavalent chromium. The
remedial effectiveness of this innovative in situ technology was
monitored over a one year period. The success of this small-scale test has
prompted a full-scale implementation of the technology at the site for late
spring 1996. (This is an abstract of a proposed presentation and does not
necessarily reflect EPA policy.)

Key words: zero-valent iron, in situ reactive barrier walls, chromate, ground
water remediation, geochemistry.

Oral presentation in metals session.

14 • CALCIUM AND MAGNESIUM INTERFERENCE STUDIES FOR THE
BINDING OF HEAVY METAL IONS IN SOLUTION BY MEDICAGO SATIVA (ALFALFA)

J.L. Gardea-Torresdey, K.J. Tiemann, J.H. Gonzalez, and O. Rodriguez,
Department of Chemistry, University of Texas at El Paso, El Paso, TX, 79968

Previous batch laboratory experiments performed to determine the potential
ability of seven different varieties of Medicago sativa (Alfalfa )
revealed that the African shoots population was able to efficiently bind
copper(II) and nickel(II) from aqueous solutions. Batch laboratory interference
studies were performed with various calcium and magnesium concentrations (0.2
mM-0.2 M) in order to ascertain the effects of these ions on the heavy metal
binding ability of African alfalfa shoots. Results from these studies have shown
that calcium and magnesium did not greatly reduce the binding of cadmium(II),
copper(II), lead(II), nickel(II), and zinc(II) to African alfalfa shoots.
However, high concentrations of calcium and magnesium significantly reduced
chromium(III) binding to African shoots. In addition, all these experiments were
repeated maintaining the ionic strength constant and similar results were
obtained. Further studies are being conducted in order to determine if the same
effects can be seen under flow conditions with silica immobilized African
alfalfa shoots. The information obtained from these studies will be useful for
an innovative method of heavy metal ion removal and recovery from contaminated
waters.

Key words: bioremediation, alfalfa, Medicago sativa, interference, heavy
metal binding.

Oral presentation in metals session.

15 • THE EFFECT OF VEGETATION ON THE TRANSPORT OF HEAVY METAL
IN A CONTAMINATED SOIL: A COLUMN STUDY

S.R. Burckhard1, A.P. Schwab2, and M.K.
Banks1, 1Department of Civil Engineering, and
2Department of Agronomy, Kansas State University, Manhattan, KS,
66506

Vegetation grown in contaminated soils may provide various pathways for the
transport of heavy metals, including preferential flow paths, chelation of
metals by root exudates, adsorption/desorption, and precipitation/dissolution
reactions. This column study, designed to simulate field conditions,
investigates the changes in the soil's physical and chemical properties due to
the presence of vegetation. Changes in the water content of the soil will be
quantified as a function of time along with the growth of the plants' roots.
Leachate will be collected and the heavy metal solution species will be
quantified. The collected data will be used to assess the overall transport of
heavy metal within and out of the vegetated contaminated soil system.

Key words: vegetation, heavy metal, transport, geochemistry.

Oral presentation in metals session.

16 • APPLICATIONS OF PERMEABLE BARRIER TECHNOLOGY TO GROUND
WATER CONTAMINATION AT THE SHIPROCK, NM, UMTRA SITE

B.M. Thomson, E.J. Henry, and M. Thombre, Department of Civil Engineering,
University of New Mexico, Albuquerque, NM, 87131

The Shiprock uranium mill tailings pile in far northwestern New Mexico
consists of approximately 1.5 million tons of uranium mill tailings from an acid
leach mill which operated from 1954 to 1968. Located on land owned by the Navajo
Nation, it was one of the first tailings piles stabilized under the Uranium Mill
Tailings Remedial Action (UMTRA) project. Stabilization activities were
completed in 1986 and consisted principally of consolidating the tailings,
contouring the pile to achieve good drainage, and covering the pile with a
multi-layer cap to control infiltration of water, radon emanation, and surface
erosion. No ground water protection or remediation measures were implemented
other than limiting infiltration of water through the pile, although a
significant ground water contamination plume exists in the flood plain adjacent
to the San Juan River. The major contaminants at the Shiprock site include high
concentrations of sulfate, nitrate, arsenic, and uranium. One alternative for
remediation may be the use of a permeable barrier in the flood plain aquifer. As
proposed for the Shiprock site, the permeable barrier would be a trench
constructed in the flood plain that would be backfilled with a media that is
permeable to ground water, but would intercept or degrade the pollutants. Work
to date has focused on use of a mixed microbial population of sulfate- and
nitrate-reducing organisms. These organisms would produce strongly reducing
conditions which would result in precipitation of the metal contaminants (i.e.,
As(V) and U(VI)) in the barrier. One of the first considerations in designing a
permeable barrier is developing an understanding of ground water flow at the
site. Accordingly, a steady state numerical model of the ground water flow at
the site was developed using the MODFLOW code developed by the U.S. Geological
Survey. This model was calibrated using data collected at a suite of monitoring
wells at the Shiprock site, and then used to simulate a variety of hydraulic
alternatives. These alternatives included use of permeable barriers, use of a
combination of impermeable and permeable barriers to achieve a "funnel and gate"
effect, and manipulation of the hydraulic gradient in the flood plain through
use of infiltration trenches to increase contaminant migration rates. A
preliminary ranking system was developed to allow comparison of these
alternatives which included length of the barriers, ground water velocities (and
therefore aquifer flushing rates), and hydraulic gradient manipulation
considerations.

Key words: ground water remediation, permeable barriers, modeling.

Oral presentation in metals session.

17 • AN ELECTROCHEMICAL APPROACH FOR INVESTIGATING CORROSION
OF SMALL ARMS MUNITIONS IN FIRING RANGES

K. Bundy, M. Bricka, and A. Morales, Environmental Laboratory, U.S. Army
Engineer Waterways Experiment Station, Vicksburg, MS, 39180-6199

Spent small arms munitions have been accumulating for decades at firing
ranges operated by the DoD, law enforcement agencies, and commercial firms.
Since 1) in many cases the used bullets are outdoors and subjected to weathering
and other sources of moisture, 2) many munitions use lead alloys in their
construction, and 3) the toxicity associated with lead is well documented, there
is increasing concern that these accumulations represent a potential source of
pollution to water and soil. To guide both assessments of the severity of this
problem and potential remediation efforts at particular sites, it is necessary
to quantify how rapidly bullets are actually corroding and to learn about the
soil variables which foster electrochemical dissolution of munitions. The
corrosion behavior of iron and steel alloys in soils is well known, due to the
importance of this topic to the gas industry. Much less information is available
about the performance of lead alloys in soil, however, and no prior studies have
documented investigations of the rate of corrosion of bullets exposed to soil
conditions. This research project was undertaken to start to remedy these
deficiencies. The situation experienced by spent copper-jacketed lead bullets in
soil suggests that both galvanic corrosion and crevice corrosion mechanisms can
occur in certain circumstances. To allow these mechanisms to be potentially
operative and to facilitate linear polarization measurements, in this study M16
bullets were sectioned longitudinally and an insulated copper wire was attached.
The bullets were buried in a corrosion cell containing samples of soil taken
from Louisiana army firing ranges. Four environmental conditions were
investigated to simulate possible situations in which bullets could be exposed
to moisture in the field: rain water, acid rain, sea water, and a 50% sea
water/50% acid rain mixture. The soil moisture content was adjusted to either
15% or saturation using a Denver Instrument Co. IR-100 Moisture Analyzer. These
conditions span a rather wide range of soil corrosive aggressiveness and allow
the generality of the techniques used here to be assessed. The three electrode
technique was used to measure the corrosion response of four samples for each
moisture content/type condition listed above. Graphite rods were used for the
counter electrodes, and a saturated calomel electrode was used as the reference.
A specially constructed salt bridge was used to make the connection between the
reference electrode and the soil environment. The electrochemical measurements
themselves were conducted using a computer-controlled EG&G PARC Model 273A
potentiostat and M270 and Headstart software packages. For accurate corrosion
rate determinations in environments of high ohmic resistance such as soil, it is
essential that the value of the electrical resistance R0 of the soil
be measured. This allows compensation for the soil resistance contribution to
the nominal polarization resistance to be made. In this study the soil
resistance was first determined by applying a potential pulse to the bullet and
doing chronoamperometric monitoring. The polarization resistance (compensated
for R0 as described above), Rp, was then measured. Finally
a potentiodynamic polarization curve measurement was taken. From the latter
measurement, corrosion current Ic (a direct measure of the rate of
corrosion) could be determined using Tafel extrapolation. The anodic and
cathodic Tafel slopes, Ba and Bc respectively, were
determined via the linear regression routine of a Quattro Pro for Windows
software package. This allowed the corrosion current also to be estimated via
the Stern-Geary equation: Ic = (1/(2.3
Rp))(BaBc)/(Ba + Bc).
Corrosion potential Ec was available from these measurements and from
the Headstart program. Corrosion currents of the bullets were observed to
sensitively depend on environmental conditions. The rate of corrosion was found
to increase with decreasing pH and increasing chloride and moisture contents.
The chloride content was the most influential of these variables. High soil
resistance and noble corrosion potential were found to be associated with low
corrosion rates. This is an important result since both soil resistivity and
potential can be readily measured under field conditions. These tests have
demonstrated the validity and utility of employing electrochemical techniques to
gain insight into the corrosion of small arms munitions in soil. Tests involving
long-term exposure of bullets to these and other soil corrosion environments and
measurements of resulting weight loss are ongoing. Comparison of these two types
of measurements will allow the usefulness of electrochemical methods for
predicting the corrosiveness of different soil and precipitation/moisture
conditions to be determined. Eventually it is hoped that this work will lead to
test methods to be used in the field which will allow the status of and hazards
posed by corroding munitions in soil to be assessed. Acknowledgment: This paper
is based upon research sponsored by the U.S. Army Corps of Engineers and the
U.S. Army Environmental Center. Permission to publish this material was granted
by the Chief of Engineers.

Key words: bullets, corrosion, soil, electrochemical techniques.

Oral presentation in metals session.

18 • THE TRANSPORT OF ZINC IN SOIL AS AFFECTED BY
CITRATE

Y. He1, A.P. Schwab2, and M.K. Banks1,
1Department of Civil Engineering, and 2Department of
Agronomy, Kansas State University, Manhattan, KS, 66506

Low molecular weight organic acids released by plant roots or soil microbes
may affect the adsorption of heavy metals by soils, and thereby influence the
fate and transport of heavy metals in soils. A soil column experiment was
conducted to investigate the effect of citrate, an important organic ligand
released by plant roots, on the movement of zinc in soil. Solutions with 750 mM
Zn and varying concentrations of citrate ranging from 0 to 5,000 mM were pumped
continuously through the columns at a flow rate of 0.16 ml min-1.
Column effluent was collected daily and measured for Zn, Fe, Ca, and citrate.
Finally, the columns were cut to four sections, and a sequential extraction
experiment was performed for each section in order to investigate zinc-retaining
mechanisms, to assess the distribution of zinc in soil columns, and to obtain a
mass balance of zinc. The results showed that zinc transport rate decreased, and
the zinc-retaining capacity of soil increased with increasing citrate
concentration. This may be due to the citrate serving as a substrate for soil
microbes and the increase of biomass in soil-enhanced zinc-retaining
capacity.

Key words: zinc, citrate, transport.

Oral presentation in metals session.

19 • A COMPUTER MODEL FOR REMOVAL OF LEAD FROM CONTAMINATED
SOILS

Z.A. Samani, D. Heil, S. Hu, and A. Hanson, Civil Engineering Department, New
Mexico State University, Las Cruces, NM, 88003

Lead contamination of soils is a common problem throughout the world.
Laboratory batch test and bench scale experiments have shown that EDTA can be
used to remove lead from contaminated soils. However, due to the high cost and
laborious task associated with actual environmental remediation of a
lead-contaminated soil, there is a need to be able to predict the outcome of a
remediation process in advance in order to optimize the process and minimize the
cost. This paper describes the development and validation of a computer model
which can be used to simulate the removal of lead from a contaminated soil
column using EDTA as the chelating agent. The model is able to simulate the lead
removal from soil based on equilibrium as well as kinetic dissolution model. The
comparison of the simulated results with actual lead concentrations both in
effluent and soil shows that the model can predict the lead removal process with
reasonable accuracy.

Key words: soil remediation, lead, modeling, environment.

Oral presentation in metals session.

20 • ON CONDUCTIVITY OF SOILS WITH PREFERENTIAL FLOW
PATHS

J. Lin and R.S. Govindaraju, Department of Civil Engineering, Kansas State
University, Manhattan, KS, 66502

Laboratory soil column experiments were conducted to study the distribution
of preferential flow paths resulting from removal of colloidal size clay
particles. These experiments studied the influence of clay (kaolinite)
percentage in sand-clay mixtures and the effect of hydraulic gradients on pore
evolution. Analysis of the effluent during the experiments indicated that clay
particles were removed from the soil column, accompanied by an increase in
porosity and hydraulic conductivity. Dye experiments were conducted on the same
columns to stain the pathways where colloidal particle removal occurred. Pore
formation was fairly uniform in some cases, while other cases showed distinct
preferential flow path formation. A physically-based model was used to identify
a dimensionless parameter, G, which expresses the ratio of detachment and
deposition forces at any space-time location. A model, based on equivalent media
theory, is proposed to describe the hydraulic conductivity of such soils. The
theoretical expressions for conductivity and the relationship between G and the
equivalent conductivity for such soils will be explored.

Key words: modeling, preferential flow, hydraulic conductivity, colloidal
clay particle, equivalent media theory.

Oral presentation in metals session.

21 • MODELING HEAVY METAL MOVEMENT IN A ROOTED SOIL

P. Huizenga and J.C. Tracy, Northern Great Plains Water Resources Research
Center, South Dakota State University, Brookings, SD, 57007

Prediction of the movement of heavy metals through a rooted soil requires an
understanding of both the hydrogeology and geochemistry of a site. Current
models describing the transport of dissolved constituents through a rooted soil
have been developed and shown to provide reliable predictions. Geochemical
models that predict equilibrium states for a heavy metal in a soil-water
environment have also been developed and shown to be useful. However,
incorporating a geochemical model into a soil-water transport model is
impractical in many situations due to the highly non-linear behavior of
geochemical models. An alternative to incorporating a full geochemical model
into a solute transport model is to use an empirical model representation of the
immobile and mobile phases of the heavy metal, which is calibrated using the
geochemical model. Using this approach we developed an empirical model for lead
using the MINTEQA2/PRODEFA2 geochemical assessment model for incorporation into
a root-zone fate and transport model, BIOROOT.

Key words: heavy metal, vegetative remediation, adsorption.

Oral presentation in metals session.

22 • EFFECT OF VEGETATION ON CONTAMINANT TRANSPORT IN SURFACE
FLOWS

R. Green1, R.S. Govindaraju1, L.E.
Erickson1, and L. Roig2, 1Departments of
Chemical and Civil Engineering, Kansas State University, Manhattan, KS, 66506,
and 2U.S. Army Corps of Engineers Waterways Experiment Station, 3909
Halls Ferry Road, Vicksburg, MS, 39180

It is well known that vegetation reduces contaminant transport in surface
flows. The beneficial effects of grasses and trees will be reviewed with an
emphasis on factors that can reduce or prevent the movement of heavy metals in
mine tailings from being transported in surface flows associated with
precipitation events. Available mathematical models for sediment transport in
surface flows will be reviewed. Experimental and field data on contaminant
transport in surface flows will be identified and evaluated.

Key words: surface water, metal, sediments, vegetation.

Oral presentation in metals session.

23 • UNSATURATED POROUS MEDIA FLOWS ABOUT NON-PARTICIPATING
FRACTURES

S.R. Subia1, M.S. Ingber1, and M.J.
Martinez2, 1Department of Mechanical Engineering,
University of New Mexico, Albuquerque, NM, 8713 l, and 2Engineering
Sciences Center, Sandia National Laboratories, Albuquerque, NM, 87185

Many of the flows observed in surface rock formations are unsaturated flows
through a medium containing fractures. In cases where the fractures are small
and non-connective one finds that flow may not even occur within the fractures
themselves. Under these conditions the fractures do not participate in the
background flow, but instead act as barriers which impede the flow in the
underlying matrix. From a computational point of view, discrete modeling of
these fractures in flow simulations is impractical not only because of the small
size of the fractures, but also because the fractures represent singularities in
the flow field. In general, the background flow through unsaturated porous media
is highly nonlinear because of the strong dependence of the hydraulic
conductivity on the suction head. For analytical studies, a two-parameter
exponential model for the conductivity has been used in conjunction with a
Kirchoff transformation to cast the nonlinear governing equation into a linear
form which is more amenable to solution. In this research we analyze some simple
problems using a boundary element numerical implementation of this
transformation approach and attempt to characterize the influence of small
non-connective fractures on the effective hydraulic conductivity of the
medium.

Key words: fracture, unsaturated porous media flows.

Oral presentation in metals session.

Program One
Thursday, May 23, 1996
Munitions-Contaminated Soil ·
Tampico Room

24 • TNT BREAKTHROUGH CURVES FOR AQUIFER MATERIALS FROM THE
LOUISIANA ARMY AMMUNITION PLANT, SHREVEPORT, LA

T.E. Myers and D.M. Townsend, U.S. Army Engineer Waterways Experiment
Station, 3909 Halls Ferry Road, Vicksburg, MS, 39180

The Louisiana Army Ammunition Plant (LAAP) produced ammunition for World War
II, the Korean Conflict, and the Vietnam Conflict. Some ground waters at LAAP
contain as much as 10 mg/l of 2,4,6-trinitrotoluene (TNT). Ground water
contamination with explosives at LAAP was caused by disposal of explosive-laden
wastewaters into unlined surface impoundments. The potential for plume
advancement off the LAAP boundaries is a major concern. TNT breakthrough curves
(BTCs) for four aquifer materials from LAAP were obtained under steady flow
conditions using packed columns 15.2 cm in length and 4.45 cm in diameter.
Several TNT reductive transformation products (monoamino-dinitrotoluenes,
diamino-nitrotoluenes, and azoxytoluenes) were also measured. An
advection-dispersion model with linear equilibrium-controlled sorption and
first-order decay was fit to the TNT BTCs. BTCs showed that TNT was highly
mobile in all four aquifer materials. Analysis of sectioned columns showed no
retention of TNT or TNT transformation products by the aquifer materials. Trace
amounts of monoamino-dinitrotoluenes were eluted, but no diamino-nitrotoluenes
or azytoluenes were eluted. In general, retardation by sorption was low, and
disappearance (reductive transformation, irreversible sorption, etc.) was almost
negligible. The TNT BTCs for LAAP aquifer materials are in sharp contrast to TNT
BTCs obtained in previous studies of soils from Vicksburg, MS, in which
reductive transformation to diamino-nitrotoluenes accounted for sixty percent of
the TNT introduced to soil columns. The mobility difference for LAAP aquifer
materials and Mississippi soils is hypothesized to be caused by differences in
aquifer material or soil oxidation-reduction potential under saturated
conditions.

Key words: trinitrotoluene, ground water, sorption, transformation,
transport.

Oral presentation in munitions-contaminated soil session.

25 • PEROXONE TREATMENT OF EXPLOSIVES-CONTAMINATED GROUND
WATERS

M.E. Zappi1, J. Miller2, E. Toro2, R.
Cerar3, and R. O'Donnell3, 1Department of
Chemical Engineering, Mississippi State University, Starkville, MS, and
2USAE Waterways Experiment Station, Vicksburg, MS, and
3U.S. Army Environmental Center, Edgewood Arsenal, MD

The U.S. Department of Defense has numerous sites that contain ground water
that has been contaminated with explosive compounds due to past military
activities. Current technology for remediation of these ground waters are
activated carbon and UV-based chemical oxidation. Recent efforts within the
Department of the Army research community has resulted in the development of
peroxone oxidation for treating explosives-contaminated ground waters. Peroxone
utilizes the reaction between ozone and hydrogen peroxide, which forms the
hydroxyl radical, to destroy aqueous-based contaminants. This ozone-hydrogen
peroxide reaction does not require ultraviolet light; thereby, it may be
considered a "dark" oxidation process. Recently, our research team using
bench-scale reactors compared the removal rates of TNT, RDX, HMX, and TNB
obtained by various candidate advanced oxidation processes (including peroxone).
These results indicated that peroxone was quite competitive in terms of the rate
and completeness of contaminant removal to the other more traditional UV-based
AOPs. Based on the positive bench results, a pilot-scale peroxone system was
operated at Cornhusker AAP. Results of this effort indicated that an optimum
ratio of hydrogen peroxide-ozone of 0.3 produced an effluent acceptable quality
within 30 minutes of treatment. This presentation will summarize both the bench-
and pilot-scale activities with particular emphasis placed on process
optimization.

Key words: peroxone, explosives, ground water, process optimization.

Oral presentation in munitions-contaminated soil session.

26 • FEDERAL INTEGRATED BIOTREATMENT RESEARCH CONSORTIUM:
FLASK TO FIELD

K.T. Preston, Army Corps of Engineers, Waterways Experiment Station,
Vicksburg, MS, 39180

Composting is currently being considered, piloted, or demonstrated for use as
a bioremediation technique for many types of contaminated soils. The current
status of composting of explosives, heavy poly-aromatic hydrocarbons (PAHs),
polychlorinated biphenyls (PCBs), and chlorinated solvents contaminated soils
will be discussed. Relevant process principles involving microbial kinetics,
mass and heat transfer, and energy balances will be developed and examined. From
the completed investigations of explosive-contaminated soils a step-by-step
bench-scale protocol has been written (in editing) to support the development of
composting for other contaminants in the future based on earlier contaminated
soils investigations. Overall outlook for composting will be discussed.

Key words: composting, bioremediation, explosives.

Oral presentation in munitions-contaminated soil session.

27 • SCREENING FOR REMOVAL OF TNT AND RDX BY SUBMERSED AND
EMERGENT PLANT SPECIES FROM CONTAMINATED GROUND WATER

E.P.H. Best1, M.E. Zappi2, H.L.
Fredrickson2, S.L. Larson2, S. Sprecher2, and
J. Miller2, 1AScI Corporation, 3402 Wisconsin Avenue,
Suite #5, Vicksburg, MS, 39180, and 2U.S. Army Corps of Engineers,
Waterways Experiment Station, Vicksburg, MS, 39180

The differential ability of aquatic plant species to remove TNT and RDX from
explosives-contaminated ground water was investigated under laboratory
conditions. Two screening experiments were performed, utilizing contaminated
ground water from Department of Defense ammunitions plants (AAP). TNT and RDX
concentrations from the Milan AAP were 2,200 and 3,000 µg l-1, and at
the Iowa AAP, 700 and 13,000 µg l-1, respectively. In each experiment
10 plant species were incubated with ground water for 10 days. Water without
plants or sediment, and water with autoclaved and unautoclaved sediment served
as controls. The concentrations of the contaminants in the water were monitored
regularly. All plant species significantly increased amount and rate of TNT
removal over that in water alone. The most effective species were elodea, sago
pondweed, Eurasian watermilfoil, stonewort, curlyleaf pondweed, waterstargrass,
and reed canary grass. Removal curves were extrapolated to the EPA-mandated
potable water level of 2 µg l-1 to calculate the residence time
requirements for TNT clean-up. Clean-up periods in the screening using MAAP
ground water were 56 days for water without plants or sediment, 16 to 56 days
for water with sediment, and 4 to 5 days for submersed plants at a density of 9
g fr wt l-1. Here N amendment stimulated TNT removal. Clean-up
periods in the Iowa AAP screening were 61 days for water without plants or
sediment, 31 for water with sediment, and 2 to 49 days for water with
submersed/emergent plants present. Correlation analysis indicated that TNT
removal from water is plant-mediated, and that required residence time decreases
with increasing plant biomass. Plant effects on RDX removal were more variable
and an order of magnitude slower than in TNT. The most effective species were
sago pondweed, Eurasian watermilfoil, parrotfeather, curlyleaf pondweed, reed
canary grass, fox sedge, and common arrowhead. Estimates of predicted residence
times for clean-up to 2 µg l-1 in the MAAP study were 627 days for
water without plants or sediment, and 50 to 297 days for water with plants. In
the IAAP study, residence times for clean-up were 91 days for water without
plants or sediment, 39 to 51 days for water for sediment, and 39 to 75 for water
with plants. Correlation analysis indicated that RDX removal from water was not
directly plant-mediated; however, the required residence time for this explosive
increased with oxygen concentration in water. This suggests the potential
involvement of facultative and/or obligate anaerobic microorganisms in RDX
removal, or the existence of non-aerotolerant enzymes. Indications of reductive
metabolic pathways of TNT were detected in incubation water and plant
material.

Key words: ground water, explosives, phytoremediation, constructed
wetlands.

Oral presentation in munitions-contaminated soil session.

28 • BIOREMEDIATION OF SOLID TNT PARTICLES IN A SOIL SLURRY
REACTOR: MASS TRANSFER CONSIDERATIONS

P.C. Gilcrease, V.G. Murphy, and K.F. Reardon, Department of Chemical and
Bioresource Engineering and Center for Environmental Toxicology and Technology,
Colorado State University, Ft. Collins, CO, 80523

The bioremediation of 2,4,6-trinitrotoluene (TNT) contaminated soils is
complicated by the fact that TNT is often present in the form of solid particles
as large as 1 cm in diameter. Since biodegradation is an aqueous phase process,
the dissolution of solid TNT particles can limit the overall treatment rate.
Slurry-phase reactors can be used to enhance the biodegradation of solid TNT
particles since dissolution rates are increased with agitation. The focus of
this research was the effect of solid/liquid mass transfer on the slurry phase
biotreatment of solid TNT particles. Special emphasis was placed on the effects
of particles other than TNT. Soil slurry bioreactors contain up to 50 wt%
solids, most of which are soil particles rather than TNT. Non-TNT solids (soil)
can potentially affect the biodegradation of TNT solids in three ways: 1)
changes in kLa due to slurry properties and TNT particle attrition, 2) biofilm
resistances due to association of the biomass with the solid phase, and 3)
sorption of TNT by other solids. In this study, the first two processes were
investigated using idealized experimental systems; their importance in real soil
slurry bioreactors is discussed. Results indicate that attrition of TNT
particles can significantly increase the overall degradation rate.

Key words: trinitrotoluene, bioremediation, soil slurry bioreactor, mass
transfer.

Oral presentation in munitions-contaminated soil session.

29 • PHYTOREMEDIATION OF TNT-CONTAMINATED WATER: BENCH-TOP
FLOW THROUGH REACTOR STUDIES

V.F. Medina1, S.C. McCutcheon2, and N.L.
Wolfe2, 1National Research Council and 2U.S.
Environmental Protection Agency, USEPA-NERL, 960 College Station Road, Athens,
GA, 30605

The degradation of trinitrotoluene (TNT) in water using plant enzymes was
investigated. An integrated approach using batch experiments and continuous plug
flow reactors was used. Kinetic parameters were investigated at different
contaminant loading rates. Breakdown product accumulation and destruction were
monitored. The experiments provided information for upscaling the process to
create full-scale phytoremediation wetland reactors.

Key words: phytoremediation, trinitrotoluene, explosives, munitions,
remediation.

Oral presentation in munitions-contaminated soil session.

Program Two
Tuesday, May 21, 1996
Chemical Technologies · Cozumel
Room

30 • CARBON TETRACHLORIDE DECHLORINATION IN WATER USING
BINARY METAL SYSTEMS

T. Boronina, I. Lagadic, and K.J. Klabunde, Department of Chemistry, Kansas
State University, Manhattan, KS, 66506

Carbon tetrachloride dechlorination in water has been investigated in the
presence of zinc nanoparticles and zinc particles doped with silver, palladium,
and nickel. Gas chromatography, mass spectrometry, infrared spectroscopy, powder
x-ray diffraction spectroscopy, and Atomic Force Microscopy (AFM) were used to
follow the reaction progress. AFM studies of the zinc surface (Zn dust pressed
in pellet at 7,000 psi) have demonstrated consecutive surface change during the
carbon tetrachloride degradation. Before the reaction the surface
"macrostructure" appeared to be quite regular and consisted of units 3-8 mm in
diameter. In addition, there were particles about 100 nm in diameter on the top
of each unit. Over the course of the reaction particle size on the top of the
units increased and later further erosion of the units took place.

Key words: carbon tetrachloride, dechlorination, water, metal particles,
Atomic Force Microscopy (AFM).

Oral presentation in chemical technologies session.

31 • DECHLORINATION OF TRICHLOROETHYLENE BY ZERO-VALENT
METALS IN AQUEOUS ENVIRONMENTS

W. Li, K.J. Klabunde, T. Boronina, D. Zhang, and I. Lagadic, Department of
Chemistry, Kansas State University, Manhattan, KS, 66506-3701

Electroactive metals, for example Zn, especially reactive forms such as
cryo-Zn may participate in reductive dechlorination of chlorocarbons under
neutral pH conditions. This can be useful when dealing with persistent ground
water contaminants, in particular trichloroethylene (TCE). We have studied this
process in some detail, and have found the major degradative products are the
dichloroethene isomers, plus smaller yields of some other chlorinated
hydrocarbons. The enhanced reactivity of Zn as promoted by other metals and
bimetallic forms, and the multiple degradation pathways will be discussed.
Investigation of morphological changes by Atomic Force Microscopy will also be
reported.

Key words: trichloroethylene, trichloroethane, dichloroethene,
dechlorination, reduction.

Oral presentation in chemical technologies session.

32 • DECHLORINATION OF CARBON TETRACHLORIDE WITH IRON: CARBON
MASS BALANCE AND EFFECT OF OXYGEN ON DECHLORINATION PATHWAYS

B.R. Helland, P.J.J. Alvarez, and J.L. Schnoor, The University of Iowa, Iowa
City, IA, 52242

Abiotic dechlorination of carbon tetrachloride (CCl4) with
zero-valent iron (Fe0) has been reported. Nevertheless, the chemistry
of the iron surface and the effect of dissolved oxygen (DO), often present in
ground water and industrial effluents, in determining dechlorination rates and
products have not been well defined. Furthermore, a complete mass balance on
carbon has proven elusive, prohibiting the determination of the ultimate fate of
CCl4. CCl4 dechlorination with two distinctly different
Fe0 materials was observed under three DO concentrations in
continuously-mixed batch reactors. Reaction rates and products were monitored
during the dechlorination reactions to investigate the interaction between
different Fe0 surfaces, CCl4, and DO. The primary
identified products of CCl4 dechlorination were CHCl3,
CH2Cl2, CO2, and CO. An unidentified end
product and at least one transient product were also observed, and efforts to
identify and quantify these compounds continue in our laboratory. In addition, a
small amount of chlorinated residue was found on the Fe surface. This residue
contained a number of distinct compounds which were tentatively identified as
short chain polychlorinated alkanes and alkenes. The mass balance on
C1compounds and the distribution of dechlorination products under the
various reaction conditions employed are discussed. A significant difference in
dechlorination rates between the two Fe substrates was observed. Both the
surface area and chemical composition of the surface appear to be factors in the
reactivity of the substrate. DO initially present in the reactors significantly
influenced the dechlorination rates and the distribution of dechlorination
products. The presence of DO apparently resulted in the oxidation of reaction
intermediates, as indicated by the generation of more CO and CO2
under initially oxic conditions. DO also oxidized the Fe surface, slowing the
dechlorination process.

Key words: carbon tetrachloride, iron, dechlorination, oxygen, fate.

Oral presentation in chemical technologies session.

33 • CHLOROFORM TRANSFORMATION BY A METHANOGENIC CONSORTIUM
UTILIZING ZERO-VALENT IRON AS ULTIMATE ELECTRON DONOR

L.J. Weathers, G.F. Parkin, and P.J.J. Alvarez, Department of Civil and
Environmental Engineering, The University of Iowa, Iowa City, IA, 52242

Chloroform (CF) was rapidly transformed in methanogenic incubations fed
zero-valent iron as the sole electron donor. Pseudo-first order rate constants
were at least twenty times greater in incubations containing 40-mesh iron
filings and methanogenic cell suspension compared to incubations containing iron
and autoclaved cell suspension, iron and cell-free supernatant, and cell
suspension only. An acetate-enriched, mixed, methanogenic culture was used as a
source of cell suspension. Apparently, methane production was supported by
water-derived hydrogen produced by anaerobic corrosion of the added iron.
Replacing the N2/CO2 headspace in iron-free cell
suspension bottles with H2/CO2 headspace increased rates
of methanogenesis and CF transformation. Dichloromethane (DCM) was produced
concurrent with CF degradation in iron-cell suspension incubations, but at less
than equimolar amounts. Methane production in bottles containing iron and cell
suspension decreased when amended with CF, indicating inhibition of
methanogenesis by CF. Bromoethanesulfonate (BES), a methanogen-specific
inhibitor, inhibited methanogenesis and CF transformation when added to cell
suspension bottles with a H2/CO2headspace. BES also
inhibited methanogenesis when added to iron-amended cell suspension with an
initial N2/CO2 headspace. Vancomycin, an inhibitor of
eubacteria, had no effect when added, discounting the potential involvement of
homoacetogens. In column reactors with an influent CF concentration of about 1.5
mM, CF was nondetectable in the effluent of a column reactor packed with steel
wool and seeded with methanogenic cell suspension, while the CF concentration in
a similar column not seeded with methanogenic cell suspension averaged about 0.4
mM. These results suggest that methanogens can couple the anaerobic biocorrosion
of elemental iron with the biodehalogenation of CF, and that this process is
sustainable.

Key words: bioremediation, zero-valent iron, chloroform.

Oral presentation in chemical technologies session.

34 • DESTRUCTIVE ADSORPTION OF CHLOROCARBONS ON CALCIUM
OXIDE

O. Koper, I. Lagadic, and K.J. Klabunde, Chemistry Department, Kansas State
University, Manhattan, KS, 66506

The destructive adsorption of carbon tetrachloride and trichloroethylene on
two types of calcium oxide was studied. The intrinsic differences between the
nanoscale, autoclave-prepared calcium oxide (AP-CaO) and conventionally-prepared
calcium oxide (CP-CaO), such as the number and the nature of hydroxyl groups on
the surface, the morphology of the surface, and the particle size, were
determined. Decomposition ability and the products were studied by various
techniques, including gas chromatography, mass spectrometry, powder x-ray
diffraction spectroscopy, elemental analysis and infrared spectroscopy. Infrared
spectroscopy was also used to observe the interactions between the chlorocarbon
and the oxide.

Key words: calcium oxide, chlorocarbon, decomposition.

Oral presentation in chemical technologies session.

35 • DESTRUCTIVE ADSORPTION OF 2-CHLOROETHYL ETHYL SULFIDE BY
MAGNESIUM OXIDE

E.M. Lucas and K.J. Klabunde, Department of Chemistry, Kansas State
University, Manhattan, KS, 66506

Studies were performed to look at the potential use of nanoscale MgO for the
destructive adsorption of hazardous military compounds. Room temperature
reactions were done with nanoscale MgO and 2-chloroethyl ethyl sulfide (a
mustard gas mimic). Preliminary results indicate that dehydrochlorination of the
2-chloroethyl ethyl sulfide to produce ethyl thio ethene took place. Further
studies include observation of reaction rates and carrying out kinetic analyses
by using FT-IR, gas chromatography and UV-Vis.

Key words: nanoparticles, MgO, adsorption.

Oral presentation in chemical technologies session.

36 • EFFECT OF REDOX ENVIRONMENT ON OXIDATION OF
PENTACHLOROPHENOL WITH MANGANESE OXIDE

R.A. Petrie1, R.C. Sims1, J.E. McLean1, and
P.R. Grossl2, 1Division of Environmental Engineering and
Utah Water Research Laboratory, Utah State University, Logan, UT, 84322-4110,
and 2Department of Plant Soils and Biometerology, Utah State
University, Logan, UT, 84322-4820

The fate of pentachlorophenol (PCP) in the subsurface environment of the
Libby, Montana, Superfund site is not well understood, especially with regard to
reaction with subsurface manganese present at the site. Reduction-oxidation
(redox) reactions are predicted to influence the fate, mobility, and
interactions of PCP and inorganic soil minerals in subsurface environments. A
potentiostat apparatus was designed and constructed to characterize the abiotic
interactions of PCP on manganese oxide surfaces at specific ground water redox
environments. The optimal redox potential and pH were determined for the
oxidation of PCP at 11°C (ground water temperature). Based on experiments
conducted at Utah State University (USU), oxidation of PCP is hypothesized to
yield polymerized products with humic substances and mineral colloids. These
reactions are hypothesized to lead to a reduction in mobility and toxicity, and
an enhancement of PCP humification. Oxidation products of PCP and manganese were
characterized using Infrared (IR) and Raman spectroscopy to elucidate the
chemical composition and nature of polymerization of the reaction products.
Results are being used to determine the reactivity of PCP with manganese as a
function of the subsurface redox environment and to assist in interpretation of
field scale results regarding PCP attenuation under natural or engineered
conditions.

Key words: pentachlorophenol, redox, ground water, remediation,
humification.

Oral presentation in chemical technologies session

37 • PHOTOCATALYTIC DEHALOGENATION OF CHLORINATED COMPOUNDS
WITH 2-PROPANOL AND ACETONE AS SOLVENTS

N. Hollan1, C. Finstad1, R.G. Arnold1, and
E.A. Betterton2, 1Department of Chemical and Environmental
Engineering, University of Arizona, Tucson, AZ, 85721, and 2Physical
and Atmospheric Sciences, University of Arizona, Tucson, AZ, 85721

In the presence of ultraviolet light, carbon tetrachloride (CT) was rapidly
degraded to chloroform and other unidentified products in a three-solvent system
consisting of isopropanol, acetone, and water. This reaction has not been
described previously. The reaction mechanism and kinetics were explored by
altering the fractional composition of the three-solvent system or the
concentration of the target compound and measuring the rate and products of
dehalogenation reactions. Light was provided via an optical fiber and quantified
using actinometry in order to determine process quantum efficiency. Half times
for CT destruction less than 1.0 h were commonly observed. The principal
wavelengths driving the photocatalytic reaction were 220 £ l £ 310 nm, within
the absorbance spectrum of acetone. Use of sunlight for photocatalysis in this
system is under investigation.

Key words: remediation, photocatalysis, dehalogenation.

Oral presentation in chemical technologies session.

38 • ACCELERATED PHOTODEGRADATION OF AROMATIC COMPOUNDS WITH
HYDROGEN PEROXIDE IN AN EMBEDDED TITANIUM OXIDE REACTOR

Q. Yan, S. Kapila, and S. Kesari, Department of Chemistry and Center for
Environmental Science and Technology, University of Missouri-Rolla, Rolla, MO,
65409-0010

The presence of synthetic organic contaminants in ground water systems is a
matter of concern. A number of processes have been investigated for removal and
degradation of these contaminants. Photodegradation offers a potential for a low
cost and environmentally-benign remediation technology. In recent years,
acceleration of the process has been investigated either through the use of
homogeneous sensitizers or with heterogeneous semiconductor photocatalysts such
as titanium oxide (TiO2). The effectiveness of combining sensitizers
and photocatalysts, however, had not been investigated and was the subject of
the present study. The investigations were carried out with a flow-through
reactor. The reactor consisted of two concentric tubes. The inner tube was made
of fritted borosilicate glass. A tight-fitting UV transmitting fused silica tube
served as the outer tube or envelope. A layer of TiO2 (anatase
crystalline form) was fused onto the borosilicate tube. Irradiation was provided
with a xenon arc lamp. Aqueous solutions of selected contaminants
(trichloroethylene, naphthalene, phenanthrene, trichlorophenol, and
pentachlorophenol) were circulated through the reactors. Degradation
efficiencies of contaminants were monitored at varied pH and hydrogen peroxide
(H2O2) concentrations. Chemical analysis of treated
solutions showed that measurable degradation occurred in all irradiation
experiments. The highest degradation efficiencies were obtained under basic pH
in the presence of H2O2.

Key words: photodegradation, embedded TiO2, pentachlorophenol.

Oral presentation in chemical technologies session.

39 • DESTRUCTIVE ADSORPTION OF ENVIRONMENTAL TOXINS UTILIZING
CALCIUM OXIDE AND TRANSITION METAL OXIDE-SUPPORTED CALCIUM OXIDE
NANOPARTICLES

S. Decker and K.J. Klabunde, Department of Chemistry, Willard Hall, Kansas
State University, Manhattan, KS, 66506-2502

The destruction of chemical models from several classes of environmental
toxins has been investigated. The environmental toxins examined in this study
were carbon tetrachloride, dimethyl methyl phosphonate, carbon disulfide, and
carbonyl sulfide. Calcium oxide and transition metal oxide-supported calcium
oxide nanoparticles synthesized via an aerogel method possess a much higher
surface area than commercially-available calcium oxide. Due to this high surface
area, the particles are capable of adsorbing and reacting with large amounts of
toxins. Experimentally, the toxins are vaporized and pulsed over a bed of the
particles where they readily adsorb and react with the calcium oxide to produce
environmentally-benign products such as calcium chloride and carbon dioxide.

Key words: environmental toxins, destructive adsorption.

Oral presentation in chemical technologies session.

Program Two
Wednesday, May 22, 1996
Chemical Technologies · Cozumel
Room

40 • USING FERRATE TO REMOVE HYDRAZINES FROM WASTE WATER

M.D. Johnson, B. Hornstein, and R. Wingo, Department of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, NM, 88003

Hydrazine and related compounds have been used for fuels in rocket propulsion
systems. Similar compounds have also been used or produced in the textile dye
industries. Treatment of wastewater streams from such industries remains a
problem. In view of this, we have investigated the ability of ferrate,
[FeO4]2-, to oxidize hydrazine and structurally similar
compounds. Ferrate represents a new alternative treatment procedure for the
rapid chemical oxidation of organic wastes which is safer than ozone or chlorine
and has no undesirable side products, such as with permanganate. The aerobic
ferrate oxidation of hydrazines produces molecular nitrogen and ferric
hydroxide: [FeO4]2- + N2H4 (aq)
--> N2(g) + Fe(OH)3(s). This reaction and others have
been studied in detail and the results will be reported. Other potential uses
for ferrate in waste treatment will be discussed. In order to provide a vehicle
for the use of ferrate flow streams, we have begun exploration of trapping
ferrate into a variety of matrices. The results of these preliminary studies
will also be outlined.

Key words: remediation, wastewater, ground water.

Oral presentation in chemical technologies session.

41 • REVIEW OF THE GALVANIC STRIPPING PROCESS FOR USE IN
TREATING OXIDIZED METAL WASTES

C.M. Chang, H. Gu, and T.J. O'Keefe, Graduate Center for Materials Research,
University of Missouri-Rolla, Rolla, MO, 65409-1170

A new process which is applicable for the treatment of waste residues
associated with the metals industry is currently being developed. The unique
part of the technology is the use of solid metal reductants in organic solvent
systems to spontaneously remove contained impurity ions. The engineering
options, termed simultaneous or separate shipping, that can be used in a flow
sheet design using the galvanic stripping process are described. In addition,
the effects of various operating parameters on the efficiency of the process are
described. Examples of the variables which influence the process kinetics
include the type of metal or alloy uses, the impurity ion concentration, the
chemical concentrations of the active organic and aqueous solutions, and their
oxygen contents. Tentative flow sheets of how the process could be used in the
treatment of iron-zinc neutral leach residue from an industrial operation are
discussed.

Key words: solvent extraction, metallurgy, oxidized waste, iron, zinc.

Oral presentation in chemical technologies session.

42 • DEVELOPMENT OF POLAROGRAPHIC FIELD SENSORS FOR HEAVY
METAL DETECTION

K. Bundy, D. Berzins, and P. Taverna, Department of Biomedical Engineering,
Tulane University, New Orleans, LA, 70118

Environmental pollution is a problem in all industrialized countries, and
heavy metal contamination of water and sediment is often of major concern.
Monitoring of contaminant levels usually entails site sampling and, later,
analysis in the laboratory. There is a pressing need, however, for accurate and
sensitive methods to determine metallic concentrations at polluted field sites
directly. Also, to most completely assess the impact of pollution, there is a
need for methods to discern the specific chemical forms present at the site.
Both needs can potentially be satisfied with field sensors based upon
polarographic techniques. Polarography is an electrochemical method in which
reduction occurs upon an electrode substrate. The magnitude of the associated
current is proportional to the concentration of the substrate being reduced. The
potential at which the current is maximized (the half-wave potential) is unique
for each metal (and even for each oxidation state of the metal). Such
polarographic apparatus can more easily be adapted to field use compared to
other analytical techniques such as GFAAS or ICP-AES. The most difficult aspect
of designing such an instrument appears to be the electrode substrate. The
research project described here is aimed at demonstrating the feasibility of
this field sensor concept. The experimental system consists of an EG&G M273
potentiostat (controlled by an IBM PS/2 computer) and EG&G M270
electrochemical analysis software. The measurements are conducted using the
three electrode technique. A saturated calomel electrode serves as the
reference; graphite rods are used for the working and counter electrodes. The
three electrodes are placed in a cell containing a fluid appropriate for the
analysis known as the supporting electrolyte. Our first experiments focused on
determining which polarographic or voltammetric technique (cyclic, linear sweep,
normal pulse, differential pulse, square wave, or sampled DC) produced the most
reliable results using graphite electrodes to detect known Pb+2
concentrations added to water. Cyclic voltammetry was observed to be the most
promising. The simulated field test apparatus described above was then used to
conduct cyclic voltammetric measurements of samples obtained from Bayou
Trepagnier near Norco, Louisiana. The first set of experiments extracted lead
(Pb+2) from spoil bank samples using methods that would be practical
to implement in the field (room temperature acid digestion for 5 minutes in 0.15
M HCI) to leach out metal ions and filtering the liquid sample to free it of
suspended particles. These specimens were also tested for metallic content using
differential pulse polarographic methods used routinely in our laboratory for
heavy metal analysis. Generally, good agreement was found between the laboratory
and simulated field methods, and the results of each were well correlated with
those of other studies that have previously monitored heavy metal concentration
in the Bayou Trepagnier area. In a second series of experiments, assays were
done for Pb+2 content of water samples obtained from the Bayou
Trepagnier site. Here the agreement between the field cyclic voltammetry and
laboratory differential pulse polarography testing was more problematical due to
greater difficulty in detecting the much lower lead levels in the water
(compared to the spoil bank). This result indicated the need for improved field
sensor electrode sensitivity. Further experiments were then conducted to see if
the situation could be improved using graphite electrodes with increased surface
area. The ratio of peak to total (i.e. peak plus hysteresis) current in cyclic
voltammograms of Pb+2 in water taken with graphite electrodes of
various lengths scaled linearly with increasing surface areas over more than an
order of magnitude. This observation provides optimism that this remote sensor
concept can be adjusted to provide accurate measurements in situ for lead
and other heavy metals, since graphite is available in a variety of porous and
fibrous forms with high specific surface area. Besides sensing element
optimization, a number of additional steps must be taken to develop a sensor
that is practical for field use. A portable, battery-powered potentiostat
compatible with a laptop computer (for measurement control, data acquisition,
and data storage) must be available. A kit must be on hand containing reagents
that can practically extract various heavy metals of interest from polluted
samples at room temperature in reasonable time periods, syringe filters for
separation of aqueous from particulate matter, and supporting electrolytes that
can safely be handled while still providing adequate detection threshold
sensitivity. Research aimed at developing these components is ongoing. In
conclusion, heavy metal pollution assessment can be improved with the
development of sensors which can be deployed in the field directly. This will
allow easier identification of pollution "hot spots" and will minimize sample
storage life concerns in speciation studies. Polarographic methods appear to be
a promising basis for such sensors.

Key words: polarography, metal, field sensors, pollution monitoring.

Oral presentation in chemical technologies session.

Technology Transfer and Analytical Methods · Cozumel Room

43 • IMPROVED HYDROCARBON DETECTION

J.L. Bratton1 and W.L. Bratton2, Applied Research
Associates, Inc., 14300 San Mateo Blvd. N.E, Suite A220, Albuquerque,
NM, 87110, and 2105A Waterman Road, South Royalton, VT, 05068

The rapid in situ delineation of hydrocarbon contamination has the
potential for significantly reducing the total cost of remediating many
thousands of contaminated sites. These cost reductions are possible because of
the speed of the site characterization, the reduction in the number of
laboratory samples required, the reduction in drilling waste which must be
disposed of, a better definition of the contaminated zone, and the ability to
monitor at a number of locations during remediation. This is possible with a new
minimally invasive hydrocarbon detection device, the Fuel Fluorescence Detector
(FFD). The FFD operates on fluorescence principles and is deployed in the tip of
a Cone Penetrometer to make continuous measurements of the contamination as the
probe is pushed into the ground. This paper will describe the FFD and show
laboratory and field data gathered at contaminated sites.

Key words: site characterization, hydrocarbon detection, fluorescence, in
situ measurements, cone penetrometer.

Oral presentation in technology transfer and analytical methods.

44 • IDENTIFICATION OF PENTACHLOROPHENOL IN ALLUVIAL SOILS
UTILIZING IMMUNOASSAY FIELD METHODS, GRAND TETON NATIONAL PARK, WYOMING-A CASE
STUDY

A.B. Flynn and M. Bell, The Roybal Corporation, 7600 E. Eastman, Suite 200,
Denver, CO, 80231

Immunoassay (IA) field methods were utilized to identify the presence of
pentachlorophenol (PCP) in alluvial soils. IA-supported field decisions were
used to determine the limits of excavation during remediation of a former
pole-dipping station, significantly decreasing the volume of hazardous waste
generated for disposal. Semi-qualitative test results were obtained using IA
methods in less than one hour. Immunoassay field tests were compared to
analytical laboratory test results. One in 12 field samples indicated a
false-positive test result. On-site testing decreased the potential for false
negative confirmatory lab samples and reduced the amount of equipment
time required for excavation and backfill of the contaminated area.

Key words: immunoassay, remediation, assessment, regulatory compliance.

Oral presentation in technology transfer and analytical methods session.

45 • POLLUTION PREVENTION AND MICROSCALE CHEMISTRY IN THE
RESEARCH LABORATORY

M.D. Erickson, J.S. Alvarado, C.-S. Lu, F. Lemley, D.P. Peterson, J.F.
Schneider, L.M. Shem, and J. Silzer, Argonne National Laboratory, 9700 S. Cass
Avenue, Argonne, IL, 60439-4837

Pollution prevention (P2) has not been sufficiently addressed in
the research laboratory. Although the amount of reagent used per experiment is
often only a few milliliters, these small amounts can quickly add up, especially
when they are aggregated across the entire research community. Effective
P2 will require operational or even fundamental changes in the
techniques and methods employed. "End-of-pipe" recycling is not practical with
small streams. Microscale chemistry is loosely defined as the application of
chemical principles and apparatus at a scale much smaller than that currently
employed by most bench chemists, reducing the volume of reagents and product by
several orders of magnitude. "Green" chemistry is an umbrella term addressing
waste minimization, P2, solvent substitution, environmentally
conscious manufacturing, maximum atom utilization, technologies for a
sustainable future, environmental security, and industrial ecology. The primary
focus of "green" chemistry over the past decade has been within the chemical
industry; adoption at the laboratory scale has been slow. Green and microscale
methods are increasingly necessary for the laboratory and research communities
as regulations tighten, the cost of waste disposal escalates, and public
scrutiny increases. The high potential for P2 in the laboratory will
be specifically illustrated with improvements in routine analytical techniques.
Routine methods for environmental and waste samples analyses are quite
prescriptive and often do not include the principles of waste minimization and
P2. Many methods require preparation of 100-fold or more excess
sample for an instrumental determination. Many methods also use reagents which
are not now considered "green." We have adapted the principles of microscale
chemistry, along with other modern analytical approaches, to develop routine
analytical methods that significantly reduce waste generation while they
maintain acceptable analytical figures of merit and achieve cost savings through
reduced reagent consumption and reduced labor costs.

he principles of P2 and waste minimization were used to develop
and test microscale adaptations to regulatory-approved analytical procedures
for the analysis of Resource Conservation and Recovery Act (RCRA) elements in
soil.

In a separate effort, we developed new procedures for preventing or
minimizing primary and secondary waste generation in chemical laboratory
operations for the analysis of polychlorinated biphenyls (PCBs).

In a third example, an integrated thermal desorption/gas
chromatography/mass spectrometer (TD/GC/MS) system was investigated as an
alternative to the customary solvent extraction, cleanup, and solvent
elimination followed by GC/MS. Because solvents are eliminated from the
analytical method, only the analyses of interest are extracted, other reagents
are eliminated, and the process can be integrated into a single flow-through
system.

Results will be reported, and the general significance of P2 in
the analytical laboratory will be discussed. The analytical applications are
illustrative of potential changes achieved by incorporating P2
principles into research and teaching laboratories. The overall importance of
P2 in the research and teaching laboratory will be discussed.
P2 in the science laboratory must be a part of our commitment to
teach the next generation how to go about the business of science. This work
supported by the U.S. Department of Energy, Assistant Secretary for
Environmental Management, Office of Technology Development, under contract
W-31-109-Eng-38. The submitted manuscript has been authored by a contractor of
the U.S. Government under contract No. W-31-109-ENG-38. Accordingly, the U.S.
Government retains a nonexclusive, royalty-free license to publish or reproduce
the published form of this contribution, or allow others to do so, for U.S.
Government purposes.

Key words: pollution prevention, green chemistry, microscale chemistry.

Oral presentation in technology transfer and analytical methods session.

Technology Transfer and Munitions-Contaminated Soils · Cozumel Room

46 • SOLIDIFICATION/STABILIZ-ATION OF METALS AND EXPLOSIVES
IN SOIL

H. Craig1, J. Wakeman2, and M. Channell3,
1U.S. Environmental Protection Agency Region 10, Oregon Operations
Office, Portland, OR, 97204, 2Seattle District Corps of Engineers,
4735 E. Marginal Way, Seattle, WA, 98124-2255, and 3U.S. Army Corps
of Engineers, Waterways Experiment Station, 3909 Halls Ferry Road, Vicksburg,
MS, 39180-6199

Metals are often co-contaminants with explosives at munitions sites and may
inhibit biological activity in soils. Metals toxicity and leachability could
preclude the use of bioremediation technologies such as composting and slurry
phase bioreactors. The current remediation approach for mixed metals and
explosives in soil is incineration followed by solidification/stabilization
(S/S). While this treatment train is effective, it is costly and requires the
use of air pollution control equipment to capture metals air emissions during
incineration. Direct S/S without incineration is a potentially cost effective
treatment option. A S/S treatability study was conducted for soils from the
Ammunition Demolition Activity (ADA) open burn/open detonation (OD/OD) area at
the Umatilla Army Depot Activity, Hermiston, Oregon, Superfund site. The primary
contaminants are metals such as lead (Pb); cadmium (Cd); nitroaromatics
2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitrobenzene (TNB); and nitramines
hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and
octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazacine (HMX). Various ratios of
portland cement and fly ash were evaluated as inorganic binders, and granular
activated carbon (GAC) as an organic binder. Leachability tests on the
solidified matrix were conducted using the EPA Toxicity Characteristic Leach
Procedure (TCLP) (EPA SW-846 Method 1311) and explosives laboratory analysis
using high performance liquid chromatography (HPLC) (EPA SW-846 Method 8330).
Results indicate an optimum S/S ratio of 30% concrete, 10% fly ash, and 5% GAC
for Umatilla soils. Average TCLP leachate reductions were 99.6%, 96.9%, 99.96%,
96.4%, 97.1%, and 99.8% for Pb, Cd, TNT, TNB, RDX, and HMX, respectively.
Leachate concentrations were below TCLP criteria for metals and below risk-based
criteria for explosives. Based on treatability results, S/S was selected as the
treatment technology for 20,000 cubic yards of ADA soils. The remedial action
contractor will further evaluate treatment mixtures of cement, fly ash, and
soluble silicates as inorganic binders, and GAC, organoclays, and rice hull ash
as organic binders.

Key words: metal, explosives, trinitrotoluene, RDX, treatment
technologies.

Oral presentation in technology transfer and munitions-contaminated soils
session.

47 • FIELD DEMONSTRATION OF ON-SITE ANALYTICAL METHODS FOR
TNT AND RDX IN GROUND WATER

H. Craig1, G. Ferguson2, A. Markos2, A.
Kusterbeck3, L. Shriver-Lake3, T. Jenkins4, and
P. Thorne4, 1U.S. Environmental Protection Agency Region
10, Oregon Operations Office, Portland, OR, 97204, 2Black &
Veatch Special Projects Corporation, 1201 Pacific Avenue, Suite 1100, Tacoma,
WA, 98402-4301, 3Naval Research Laboratory, Center for Bio/Molecular
Science and Engineering, Code 6910, Washington, DC, 20375-5348, and
4U.S. Army Corps of Engineers, Cold Regions Research and Engineering
Laboratory, Hanover, NH, 03755-1290

A field demonstration was conducted to assess the performance of eight
commercially available and emerging colorimetric, immunoassay, and biosensor
on-site analytical methods for explosives 2,4,6-trinitrotoluene (TNT) and
hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in ground water at the Umatilla
Army Depot Activity, Hermiston, Oregon, and Naval Submarine Base, Bangor,
Washington, Superfund sites. Ground water samples were analyzed by each of the
on-site methods anal results compared to laboratory analysis using high
performance liquid chromatography (HPLC) (EPA SW-846 Method 8330). The
commercial methods evaluated include the D-TECH/EM Science TNT and RDX
immunoassay test (EPA SW-846 Methods 4050 and 4051), the EnSys, Inc., TNT and
RDX colorimetric test (EPA SW-846 Methods 8515 and 8510) with a solid phase
extraction step, and the Ohmicron TNT immunoassay test. The emerging methods
tested include the antibody-based Naval Research Laboratory (NRL) Continuous
Flow Immunosensor (CFI) for TNT and RDX, and Fiber Optic Biosensor (FOB) for
TNT. Precision and accuracy of the on-site methods were evaluated using Relative
Percent Difference (RPD) and linear regression analysis. Over the range of
conditions tested, colorimetric methods for TNT and RDX showed the highest
accuracy of the commercially available methods, and the CFI showed the highest
accuracy of the emerging methods for TNT and RDX. The colorimetric method was
selected for routine ground water monitoring at the Umatilla Army Depot Activity
site, and further field testing on the NRL CFI and FOB biosensors will continue
at both Superfund sites. The primary use for these analytical methods would be
for influent and effluent monitoring for granular activated carbon (GAC) ground
water and leachate treatment systems, which are projected to operate for a
period of 10 to 30 years.

Key words: explosives, trinitrotoluene, RDX, analytical methods, ground
water.

Oral presentation in technology transfer and munitions-contaminated soils
session.

48 • FIRST PRODUCTION-LEVEL BIOREMEDIATION OF
EXPLOSIVES-CONTAMINATED SOIL IN THE U.S.

D.D. Emery and P.C. Faessler, Bioremediation Service, Inc., 12130 N.E.
Ainsworth Circle, Suite 220, Portland, OR, 97220-9009

The first production-level bioremediation of explosives-contaminated soil in
the U.S. is taking place at the Umatilla Army Depot Activity (UMDA) near
Hermiston, Oregon. Soil from munitions washout lagoons contained high
concentrations of TNT (2,4,6-trinitrotoluene) and RDX
(hexahydro-1,3,5-trinitro-1,3,5-triazine), as well as HMX
(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). In addition to these primary
contaminants, laboratory tests were performed on Tetryl
(N-2,4,6-tetranitro-N-methylaniline), 4ADNT (4-amino-2,6-dinitrotoluene), 2 ADNT
(2-amino-4,6-dinitrotoluene), 2,4 DNT (2,4-dinitrotoluene), 2,6 DNT
(2,6-dinitrotoluene), TNB (1,3,5-trinitrobenzene), DNB (1,3-dinitrobenzene) and
NB (nitrobenzene) during the pilot-scale treatability tests. The established
clean-up goal is 30 mg/kg each for TNT and RDX. Both field screening and EPA
Method 8330 analyses are being performed. Treatment time on a 2,700 cubic yard
batch (810 cubic yards of soil) is 10-12 days. A composting technique developed
by the Army Environmental Center is being used at the site. Five compost
amendments are being blended with the contaminated soil. Specialized soil fuming
equipment mixes the compost for optimum biological action and homogeneity.
Moisture and pH levels are closely monitored to ensure that thermophilic
bacteria play a dominant role in the degradation process. Homogeneity of the
compost mix ensures that all contaminants are rapidly degraded. Nearly 5,000
cubic yards of soil have been successfully treated, with more than 70% of all
analyses indicating non-detectable levels of both TNT and RDX. The U.S. Army
Corps of Engineers estimates that over $2.6 million is being saved using
bioremediation at Umatilla.

Key words: bioremediation, explosives, munitions, trinitrotoluene, RDX.

Oral presentation in technology transfer and munitions-contaminated soils
session.

Technology Transfer and Field Applications · Cozumel Room

49 • FIELD UP-SCALING OF PROCESSES ASSOCIATED WITH BEHAVIOR
OF NONAQUEOUS PHASE WASTE CHEMICALS IN HETEROGENEOUS AQUIFERS

T.H. Illangasekare, Department of Civil, Environmental, and Architectural
Engineering, University of Colorado at Boulder, Boulder, CO, 80309-0428

Remediation of aquifers contaminated with organic chemicals is a topic of
public concern as well as of considerable scientific, engineering, and
regulatory interest. In recent years, significant work has been done in basic
research on remediation of waste sites that have been contaminated with both
light and dense organic chemicals that are in nonaqueous phase. These
technologies have been primarily developed and tested in small-scale experiments
in the laboratory under idealized conditions. Field implementations have had
limited success due to a number of factors which we have identified in our own
ongoing research as well as by other investigators. These factors include
complexities created by the natural soil heterogeneities in the field, chemicals
which are in complex mixtures, complex physical, chemical, and biological
interactions which change the pore characteristics, dissolution processes that
are not very well understood, nonavailability of effective and cost-effective
field characterization techniques, and limitations in the modeling tools that
are used in the design and evaluation of the field remediation techniques, among
others. This paper presents an overview of experimental and modeling research
that is conducted at the University of Colorado that addresses the issue of
up-scaling the laboratory-developed technologies of aquifer remediation to the
field. The development of these up-scaling methodologies require the
understanding of the effects of dimensionality of flow and transport and the
role and effect of heterogeneities at various scales from soil pores to
spill-site. The parameters that control the basic processes of flow, transport,
entrapment, dissolution, and mobilization at various scales of interests have to
be identified. Methods to determine these parameters at the field scale have to
be developed. Research results that address the above issues as related to flow,
entrapment, dissolution, surfactant enhanced dissolution, and thermal
mobilization are presented. Possible use of tracer technologies for field
parameter estimation are presented. A systematic procedure for application of
the methods that have been developed in the laboratory to the field is
discussed.

Key words: organic waste, up-scaling, parameter estimation, field
characterization.

Oral presentation in technology transfer and field applications session.

50 • MINE RECLAMATION AND RESIDUAL WASTES

M.R. Deeker and J.E. Buckley, SCS Engineers, 10401 Holmes Road, Suite 400,
Kansas City, MO

Power generation stations, metal and nonmetal processing facilities, and the
cement industry will generate tens of thousands of tons of residual waste in
1996. Beneficial and sound environmental solutions to the final disposition of
these residual wastes are becoming paramount to the industry and federal, state,
and local regulatory agencies. One potential source for beneficial use of
residual waste is the mining industry. The mining industry has a window of
opportunity to convince state legislatures to allow the use of residual wastes
for mine reclamation material, additives for control of acid mine drainage,
underground mine stabilization, and numerous other activities that will benefit
both the mining industry and the industry generating the waste. The main
concerns that the mining industry will have to consider include regulatory
requirements, knowledge of the chemical compatibility of the site and waste,
detailed hydrogeologic characterization of the site under consideration, and
efficient engineering methods for transportation, handling, placement, and
environmental controls. The first issue to address is a comprehensive review of
federal, state, and local regulations to determine what requirements must be met
to use the residual waste as a reclamation material. Some states are
aggressively working with industry for beneficial uses of residual wastes while
other states consider all residual waste as either solid or hazardous waste with
corresponding regulatory disposal requirements. Beneficial use of residual waste
is not considered a remedy by federal regulators to all the issues associated
with the waste. Next, a waste characterization of the material must be performed
to identify and evaluate disposal methods for each specific waste material.
Various field and laboratory testing methods can be used to evaluate the
residual waste. Third, a hydrogeologic model of the mine area must be developed.
The hydrogeologic model presents a site-specific characterization of geologic
and hydrogeologic conditions. The model is then used to evaluate the effects the
disposal activities will have on soils and ground water at the site. Finally,
defining the transportation, handling, and placement of the residual wastes will
require a combined effort from the industry generating the waste and the mining
industry. The environmental controls will be dependent on the results of the
waste characterization and hydrogeologic characterization performed.

Key words: residual, mine reclamation, beneficial use.

Oral presentation in technology transfer and field applications session.

51 • GRAY DAUN URANIUM MINE REMOVAL ACTION, SAN JUAN COUNTY,
UTAH

D.L. Harber1 and J.D. Egnew2, 1Manti-La Sal
National Forest, 599 West Price River Drive, Price, UT, 84501, and
2Payette National Forest, P.O. Box 1026, McCall, ID, 83638

The Forest Service conducted a CERCLA removal action, with funding through
the Federal Facilities Compliance Program, during the winter of 1993-1994 at the
Gray Daun uranium/vanadium mine in San Juan County, Utah. Sidehill waste dumps
had partially obstructed, and were being eroded by, a perennial stream. Radon
was being emitted from the mine workings. Surface water transport of
radionuclides from the dumps and immediate downgradient use of this water for
culinary and agricultural purposes, along with high radon levels, prompted the
removal action. Originally the plan was to move 600 cubic yards of waste rock
back into the mine, seal 19 adits, and recontour and reclaim the surface of a
4-acre site. Placing the waste rock back in the mine was chosen as the method
with the lowest cost that would mitigate the hazard and require no future
maintenance. After the project began, approximately 6,000 cubic yards of
additional waste rock was found to be covered by colluvium. Six additional adits
were also found. The contract was modified to account for these changes. All of
the waste rock was eventually placed inside the mine. Ventilation seals were
placed in four of the adits where radon gas emissions were a problem. All but
one of the adits were permanently closed using native rock and explosives. The
remaining adit closure was designed to allow controlled access to one of two
known locations of crocodile tracks in the Morrison formation.

Key words: uranium, radon, water quality, removal action.

Oral presentation on technology transfer and field applications session.

52 • ROLE OF CARBONATION IN LONG TERM PERFORMANCE OF
CEMENTITIOUS WASTEFORMS

N. Gutierrez, S. Bin-Shafique, J.C. Walton, A. Tarquin, P. Sheeley, R. Smith,
M. Rodriguez, and R. Andrade, Department of Civil Engineering, University of
Texas at El Paso, El Paso, TX, 79968

One of the most widely used site remediation and waste disposal options is
cement-based wasteforms. Despite this fact, a definition and quantification of
processes controlling long-term performance are lacking. In the U.S., wastes are
required by law to be placed in the unsaturated zone, but wasteform performance
is evaluated using laboratory tests (TCLP, ANSI/ANS-16.1) which specify fully
water-saturated conditions. These tests ignore the potentially important role of
cement reaction with soil gases in influencing wasteform performance. The
presented research represents a combined experimental and modeling program
approach to evaluate the role of the carbon dioxide reactive component of soil
gas on the long-term performance of cementitious wasteforms. A series of
wasteforms were exposed to an accelerated environment for carbonation and then
subjected to leaching tests in water and acetic acid. Results were analyzed by
comparison of experimental data with the theoretical models of the leaching
process. In addition, diffusion coefficients were determined by fitting of the
data to the theoretical model considering a finite domain of the wasteform, and
solubility diagrams for the different species were constructed from this data.
The results indicate that carbonation increases the apparent diffusion
coefficient for unreactive species while resulting in stronger chemical binding
of metals through solid solution in calcite.

Key words: cementitious wasteforms, diffusion coefficient, carbonation.

Oral presentation in technology transfer and field applications session.

Program Two Thursday, May 23, 1996 Technology Transfer and Field
Applications · Cozumel Room

53 • MANAGING THE PUMP-AND-TREAT END GAME

V.I. Terauds, Enhanced Solutions!, 616 Central S.E., Suite 219, Albuquerque,
NM, 87102

Understanding the fate and transport of contaminants in the subsurface has
received much attention as contaminant migration affects risk assessment and
remedial design. However, understanding the subsurface changes and
transformations that occur as a result of implementing ground water remedial
actions has received much less attention, other than to say that ground water
pump-and-treat does not perform as predicted and is typically not a remedial
technology of choice to achieve aquifer cleanup. Recent research has focused on
optimizing pump-and-treat, rather than looking at the micro-scale processes that
limit significant contaminant mass removal regardless of optimal ground water
flowpath design. In analogy to the extractive industries, the environmental
remediation paradigm needs to shift such that the appropriate tools are used for
the appropriate setting, driven by an appreciation of both macro- and
micro-scale limitations on contaminant removal. In contrast to the extractive
industries, the performance goals often exceed 99.9999 percent removal
efficiencies without monetary incentive for extraction, but rather the goal of
health and environmental risk management. This presentation focuses on outlining
and understanding the different micro-scale physical, chemical, and biological
processes affected by ground water pumping and their impact on creating
reasonable performance objectives and life-cycle designs capable of achieving
remedial success. Ground water pumping affects not only contaminant
concentrations, but aquifer redox conditions, the availability of electron
acceptors, precipitation/dissolution reactions, diffusion, and other subsurface
processes. The well-known ground water pumping performance curves that reach
asymptotic levels merely reflect that there is a remedial breakover point at
which the concentration gradient stabilizes due to the increasing role of
microprocesses. Accelerating the remedial breakover point and achieving the
minimum concentration at which breakover occurs should be the goal of any ground
water pump-and-treat system as this emphasizes maximum contaminant mass removal
over time. The management of the asymptotic levels often means that ground water
pump-and-treat systems continue to operate simply to satisfy political and
permitting concerns. Instead, a proposed life-cycle design that uses subsurface
process dynamics and incorporates naturally-occurring fate and transport
processes is suggested. Tools and techniques will be discussed to manage risk
and remedial performance in a way to optimize remedial resource allocation in
terms of both time and cost.

Key words: environmental fate and transport, ground water remediation.

Oral presentation in technology transfer and field applications session.

54 • DESIGN CONSIDERATIONS OF VERTICAL VERSUS HORIZONTAL WELL
CONFIGURATIONS FOR AIR SPARGING/SOIL VAPOR EXTRACTION REMEDIATION SYSTEMS

V.A. Mast1 and K.E. Koerner2, 1School of
Civil Engineering, Oklahoma State University, Stillwater, OK, 74075, and
2Koch Industries, Inc., Wichita, KS, 67201-2338

A number of factors are considered in designing an in situ air
sparging (IAS) with associated soil vapor extraction (SVE) system for the
remediation of soil and ground water contaminated with petroleum hydrocarbons. A
system is designed, based upon established criteria, which will effectively meet
state and federal remediation standards. One of the major decisions in an
IAS/SVE system design is well configuration, specifically, the orientation of
wells, vertical or horizontal. Tradition has dictated the use of vertical wells.
However, horizontal wells are now being considered for both methods.
Specifically, three questions are posed: 1. Should vertical or horizontal wells
be used for air sparging? 2. Should vertical or horizontal wells be used for
soil vapor extraction? 3. If a horizontal orientation is recommended, should a
trench design or a directional drilled well be used? To answer these questions,
one must consider the hierarchy of criteria to be used and driving factors
analyzed.

Key words: innovative, air sparging, soil vapor extraction, directional
drilling.

Oral presentation in technology transfer and field applications session.

55 • POLLUTION PREVENTION ASSESSMENTS FOR MARINE MAINTENANCE
AND CONTAINER PRINTING INDUSTRIES

M. Erten-Unal1, J.M. Marchello1, H.
Robinson1, M. Burgess2, and G. Aydlett2,
1Old Dominion University, Department of Civil & Environmental
Engineering, KDH Room 133-A, Norfolk, VA, 23529-0241, and 2Industrial
Waste Division, Hampton Roads Sanitation District, P.O. Box 5911, Virginia
Beach, VA, 23455-0911

A unique working partnership (the Partnership) was formed between the Old
Dominion University Department of Civil and Environmental Engineering (ODU) and
Hampton Roads Sanitation District Industrial Waste Division (HRSD) to assess and
recommend pollution prevention measures at no cost to small- and medium-sized
industries in the Hampton Roads area of the Commonwealth of Virginia. The
project provided two types of industries with direct on-site technical
consultation on waste reduction, including elimination of solid and hazardous
waste, wastewater discharges, and air emissions. The two industry types were
marine maintenance and container printing industries. ODU provided on-site
pollution prevention opportunity assessments for qualifying facilities in the
selected industries. The purpose of the visits was to help the industry identify
some easy-to-implement pollution prevention and recycling options and more
comprehensive approaches to waste reduction. The findings and recommendations
were outlined in a report including cost/benefit analyses on replacing processes
and recovering waste streams. HRSD reviewed audits and reports and worked with
facilities to carry out audit recommendations in a timely manner. Follow-up
procedures included seeking opinions from participating facilities, generation
of printed information targeting industry type, and workshops focusing on
information sharing by industry type. The project supplemented and complemented
existing pollution prevention programs by working with the Virginia Department
of Environmental Quality and Office of Pollution Prevention to serve as an
expansion of service to the local level and provided a readily available
information exchange. Besides providing on-site pollution prevention assessments
to local industries, the information gathered was further developed by the
soliciting of input from additional area facilities during information exchange
workshops. Industry-specific publications were produced as a result of these
comprehensive efforts which greatly increased the impact of the individual
assessments.

Key words: pollution prevention, marine maintenance, printers.

Oral presentation in technology transfer and field applications session.

Technology Transfer and Training · Cozumel Room

56 • SUPERFUND SCIENTISTS TEACH MINORITY HIGH SCHOOL STUDENTS
SCIENTIFIC LITERACY AND CAREER DEVELOPMENT IN NOVEL YEAR-ROUND PROGRAM TIED TO
SUPERFUND INVESTIGATIONS

L.R. Sherman, L. Claudio, and P.J. Landrigan, Mt. Sinai School of Medicine,
Environmental Health Sciences Center, New York, NY, 10029

There is a need to improve scientific literacy among under-represented
minority high school students in order to increase their access to, and
participation in, environmental health careers. Recognizing that high school
students are not adequately grounded in the environmental and biological
sciences, and are ill-prepared in the methods, procedures, and concepts of
carrying out environmental research, the program has designed the first
year-round environmental health course for high school students-meshing high
school faculty and administration with Superfund scientists. Students were
taught jointly by faculty in the Mount Sinai Environmental Health Sciences
Center and their own high school teachers. The curriculum established
fundamental concepts in health and the effects of the man-made world on health
and behavior-through lectures, seminars, library, and laboratory research. The
year-round program culminated in a six-week, full-time summer internship with a
Superfund Investigator on subjects such as: "Detection of PAB and
1-Hydroxypyrene in Urine of Military Personnel"; "Lead Toxicity: Relating Human
Health Effects to Dose"; "The Transport of Polychlorinated Biphenyl Sediments in
the Hudson River"; "Hormonal Activity of Chlorinated Hydrocarbons and Related
Contaminants from New York Sediments." Through extramural support, students and
faculty sailed on the sloop "Clearwater" and learned about the history and the
ecology of the Hudson River.

Key words: minority, environmental health, scientific literacy,
polychlorinated biphenyls, hydroxypyrene, lead.

Oral presentation in technology transfer and training session.

57 • RAD WORLD/TV EARTH ENVIRONMENTAL VIDEOS

B. Powell, Waste-management Education and Research Consortium, New Mexico
State University, Las Cruces, NM, 88003

The strategy of the Department of Energy's Waste-management Education and
Research Consortium (WERC) program in developing human resources in the
EM/Waste-management field is complemented by parallel efforts to create and
sustain interest in environmental science at the pre-college level. The TV
EARTH program is an environmental science program aimed at creating and
disseminating environmental science materials for grades 6-12 using computer
animation and multimedia. The objective is to capture the interest of this age
group with imaginative presentations, scripted and animated by middle, high
school, and university students. Employing upper middle school/high school
language and educational strategies, topics such as radioactive waste storage
and underground imaging radar are demystified. All lessons are useful for
environmental courses and are linked to DOE-sponsored environmental research.
The presentation will highlight the third video, Rad World, featuring the
Waste Isolation Pilot Plant (WIPP). The video, which is accompanied by a
curriculum guide complete with activities and evaluation material, examines
radiation by studying the operation of a Geiger counter, the meaning of the
half-life of a radioactive isotope, and much more. The cast includes Alpha,
Beta, and Gamma, three "rad" characters. A central topic is low-level
radioactive waste-storage, involving information on the WIPP site. One
exceptional feature is a high school student's 3-D computer animated travel
through the tunnels of the WIPP site.

Key words: radioactive waste, environmental science, multimedia education,
nuclear waste storage, hazardous waste storage.

Oral presentation in technology transfer and training session.

58 • NATIVE AMERICAN ENVIRONMENTAL ISSUES: PUEBLO SUPERFUND
PROGRAM

C.M. Sanchez and T.L. Garcia, All Indian Pueblo Council/Pueblo Office of
Environmental Protection, 3939 San Pedro N.E., Suite B, Albuquerque, NM,
87110

In 1991, the All Indian Pueblo Council (AIPC) entered into a Superfund
Memorandum of Agreement with the U.S. Environmental Protection Agency (EPA)
Region VI to create the Pueblo Office of Environmental Protection (POEP).
Currently, the Superfund Program is the largest program at POEP and performs all
technical work in-house. POEP Superfund Progress: The POEP Superfund Program is
currently in the site assessment phase of the Superfund process. In Fiscal Year
1992, the POEP Superfund Program used aerial photos of the 19 Pueblos to
determine the number of potential hazardous waste sites. There were an estimated
500 potential sites identified within the 19 Pueblos. Communication with each of
the Pueblos has also identified potential hazardous waste sites for possible
CERCLA investigation. In Fiscal Year 1993, 12 Preliminary Assessment (PA)
reports were completed and one removal action was initiated at a heavy metal
contaminated site. The removal action was conducted at the Wall Colmonoy
Facility at Isleta Pueblo. In Fiscal Year 1994, 21 PA reports were completed and
2 Site Inspection (SI) reports were completed. During Fiscal Year 1995, the POEP
Superfund Program completed 15 PA reports and 5 SI Reports. This Fiscal Year
(1996), the Superfund Program will complete 10 PA reports and 8 SI Reports. The
Program is also researching alternative solutions for addressing some of the
potential hazardous waste sites. Tribal Issues: Because the 19 Pueblos are each
sovereign nations and unique, there are several differences and gaps associated
with the current CERCLA policies and EPA methodologies. The Superfund Hazard
Ranking System (HRS) model does not currently take into account Indian religious
and ceremonial aspects. For example, culturally significant plants, animals, and
sacred areas are not considered in this model when investigating sites. The
current process is also very lengthy and does not fit the Indian Pueblo culture
very well. The POEP Superfund Program is working with EPA Region VI to make some
considerations of site-specific situations when they arise. We are also looking
at improving the Superfund Process to fit the Indian Pueblos in the long term.
The AIPC and POEP are committed to promoting all environmental programs through
EPA, State, or private partnership arrangements. The involvement of all entities
in the State of New Mexico is vitally important to addressing and considering
Pueblo environmental issues.

Key words: Native American environmental issues, Superfund.

Oral presentation in technology transfer and training session.

Program Three Tuesday, May 21, 1996 Organic Contaminants · Coronado Room

59 • OPTIMIZATION OF CONTAMINANT REMOVAL FOR HETEROGENEOUS
SYSTEMS BY SOIL VENTING

D. Casey1, J.C. Walton1, C. Bailey1, and D.
LeMone2, 1Department of Civil Engineering and
2Department of Geological Sciences, University of Texas at El Paso,
El Paso, TX, 79968

Parameters affecting the removal of a single volatile contaminant, such as
TCE, from the vadose zone were modeled using a finite difference code. The code
solves both the multiphase energy equation and the mass balance equations for
air, water, and a contaminant. Components of the energy balance include:
sensible heat, latent heat of vaporization of water and the contaminant, and
vacuum evaporation. The relationship between the energy flux and mass fluxes of
soil water and of the contaminant indicate how venting can be optimized to
enhance removal efficiency. Soil temperature changes are more dependent on the
latent heat effects of water and a contaminant than the sensible heat effects.
Vacuum cooling at the well bore causes a localized increase in the concentration
of the contaminant.

Key words: soil venting, remediation, soil vapor extraction.

Oral presentation in organic contaminants session.

60 • REMOVAL OF HYDROCARBONS FROM CONTAMINATED WATER USING
AIR-SPARGED HYDROCYCLONE TECHNOLOGY

J.D. Miller and D. Lelinski, Department of Metallurgical Engineering,
University of Utah, Salt Lake City, UT, 84112

The air-sparged hydrocyclone (ASH) technology offers the unique opportunity
to achieve efficient removal of hydrocarbons from contaminated water at a high
specific capacity. Such an opportunity exists because the ASH system generates a
very large number of fine gas bubbles, and establishes intimate fluid dynamic
contact of these bubbles with the contaminated water. As a consequence of the
multiphase flow conditions in the ASH system, effective stripping of
hydrocarbons from various contaminated water streams can be accomplished with a
very short residence time (less than 1 second in the 2-inch diameter ASH unit).
In other words, a specific processing capacity, of more than 100 times that of
conventional air stripping technology, is possible with the advanced ASH
technology. The effectiveness of the ASH system has been demonstrated through a
number of experiments. Results from these tests shows that the ASH technology
has been effective for the removal of aromatic hydrocarbons such as benzene,
aliphatic hydrocarbons such as octane, and chlorinated hydrocarbons such as
1,2-dichloroethane, with the recovery between 97 and 99%. It should be noted
that these volatile organic contaminants cover a wide range of systems in terms
of the ease of contaminant removal from the water, with 1,2-dichloroethane being
the most difficult to remove, while octane is the easiest to remove.

Key words: hydrocarbons, stripping, air-sparged hydrocyclone.

Oral presentation in organic contaminants session.

61 • MATHEMATICAL MODELS FOR BIODEGRADATION OF CHLORINATED
SOLVENTS

X. Zhang, S.K. Banerji, and R.K. Bajpai, Department of Chemical Engineering,
University of Missouri-Columbia, W2030 EBE, Columbia, MO, 65211

Complete mineralization of chlorinated solvents by microbial action has been
demonstrated under aerobic as well as anaerobic conditions. In all the cases, it
is believed that tile biodegradation is initiated by broad-specificity enzymes
involved in metabolism of a primary substrate. Under aerobic conditions, some of
tile primary carbon and energy substrates are methane, propane toluene,
methanol, phenol, and ammonia; under anaerobic conditions, glucose, sucrose,
acetate, propionate, isopropanol, methanol, and even natural organics act as
carbon source. Published biochemical studies suggest that the limiting step is
often the initial part of the biodegradation pathway within the microbial
system. For aerobic systems, the limiting step is thought to be the reaction
catalyzed by mono- and dioxygenases which are induced by most primary
substrates, although some constitutive strains have been reported. Other
critical features of the biodegradative pathway include: 1) activity losses of
critical enzyme(s) through the action of metabolic byproducts, 2) energetic
needs of contaminant biodegradation which must be met by catabolism of the
primary substrates, 3 ) changes in metabolic patterns in mixed cultures found in
nature depending on the availability of electron acceptors, and 4) the
associated accumulation and disappearance of metabolic intermediates. Often, the
contaminant pool itself consists of several chlorinated solvents with separate
and interactive biochemical needs. The existing models address some of the
issues mentioned above. However, their ability to successfully predict
biological fate of chlorinated solvents in nature is severely limited due to the
various missing elements. This paper will provide a comprehensive review of the
existing mathematical models. Limiting step(s), inactivation of critical
enzymes, recovery action, energetics, and a framework for multiple degradative
pathways will be presented as a comprehensive model.

Key words: bioremediation, enzyme kinetics, electron acceptors,
metabolism.

Oral presentation in organic contaminants session.

62 • SURFACTANT-ENHANCED TRANSPORT OF HYDROPHOBIC ORGANIC
COMPOUNDS

H.M. Gaber, W.P. Inskeep, and J.M. Wraith, Department of Plant, Soil, and
Environmental Sciences, Montana State University, Bozeman, MT, 59717

Many surfactants enhance the apparent water solubilities of hydrophobic
organic compounds (HOCs) and may be useful in remediation of contaminated soils
or aquifers. Several studies have shown that surfactants enhance the transport
of HOCs by reducing the amount sorbed to soils, especially when surfactants are
added with the HOC in the influent solution. However, remediation practices will
generally involve application of surfactant after HOCs have "equilibrated" with
potential sorbing phases. Consequently, the objective of this study was to
compare the effectiveness of several surfactants for enhancing transport of four
representative organic contaminants when surfactants were applied with the HOC
or after the HOC was sorbed by the soil. Miscible displacement experiments were
performed using a subsurface sandy loam soil (Creston, MT) under steady-state
saturated flow conditions at a pore water velocity of xx cm hr-1. The
transport of 14C-labeled DDT, phenanthrene, pentachlorophenol (PCP),
and 1,2,4-trichlorobenzene (TCB) was monitored in the absence and presence of
four different surfactants (Triton X-100, Tween 80, lignosulfonic acid, and
hexacyclodextrin) under conditions where the surfactants were added either with
the HOC in the initial pulse solution, or after the HOC pulse was applied. In
both cases, our results show that surfactants enhance the transport and recovery
of HOCs. However, the recoveries of HOCs were much lower when surfactants were
applied after HOC sorption than when surfactants were mixed with the HOC prior
to application. Although our results support the use of surfactants for enhanced
solubilization and subsequent transport of HOCs, the recovery of HOCs from a
contaminated soil will likely be much lower than predicted based solely on
partition coefficients of HOCs in the presence and absence of surfactant.
Several factors such as desorption kinetics of aged contaminants, and ability of
surfactants to access sorption domains may be important in determining the
overall effectiveness of surfactant-based remediation technologies.

Key words: surfactants, transport, sorption, remediation, hydrophobic organic
compounds.

Oral presentation in organic contaminants session.

63 • SOLVENT EXTRACTION FOR REMEDIATION OF SOILS AT WOOD
TREATMENT SITES

Q. Yan1, S. Kapila1, A.F. Yanders2, and A.A.
Elseewi3, 1Department of Chemistry and Center for
Environmental Science and Technology, University of Missouri-Rolla, Rolla, MO,
65409-0010, 2College of Arts and Science, University of
Missouri-Columbia, Columbia, MO, 65211, and 3Environmental Solutions
Technologies, Inc., and Department of Soil Sciences, University of
California-Riverside, Riverside, CA, 92507

In recently proposed regulatory guidelines (40CFR761), the United States
Environmental Protection Agency allows remediation of polychlorinated biphenyl
(PCB) contaminated sites with ambient temperature solvent extraction. This
option holds promise for removal of organic contaminants at wood treatment
sites. A study was undertaken to evaluate the effectiveness of solvent
extraction coupled with photodegradation for removal and destruction of selected
organic contaminants in soils from a wood treatment site. The process was
evaluated through bench scale laboratory experiments and semi-pilot scale field
experiments with one-half to two ton capacity batch extractors. A binary solvent
mixture containing alkanes and butanol yielded the highest extraction
efficiencies which ranged up to 95% for contaminants such as polynuclear
aromatic hydrocarbons (PAHs), pentachlorophenols (PCPs), and polychlorinated
dibenzo-p-dioxins (PCDDs). The contaminant bearing solvent was subjected
to solar irradiation. Polychlorinated aromatics were readily degraded; e.g.,
half-life of octachloro dibenzo-p-dioxin was found to be less than 28
minutes. The residual PAHs in the solvent mixture were removed with activated
carbon and the solvent was recycled for subsequent soil extractions.

Key words: solvent extraction, soil remediation, photodegradation.

Oral presentation in organic contaminants session.

64 • SURFACTANT-ENHANCED DISSOLUTION OF NONAQUEOUS PHASE
LIQUIDS IN SANDY AQUIFER MATERIALS-EFFECTS OF DIMENSIONALITY AND SCALE

J.E. Ewing and T.H. Illangasekare, Department of Civil Engineering,
University of Colorado at Boulder, Boulder, CO, 80309

Surfactants have been used for years in the petroleum industry for enhanced
mobilization of oil from petroleum reservoirs. Because mobilization of
nonaqueous phase liquid (NAPL) contaminants can exacerbate the problem by
increasing the zone of contamination, mobilization can be undesirable.
Surfactants can also be used to enhance the dissolution of NAPLs without
mobilization. This enhanced dissolution can then be used to augment
"pump-and-treat" remediation schemes by decreasing times for clean up. Prior
experimental research on surfactant-enhanced dissolution has been confined to a
small scale. The objective of this research is to investigate the effects of
dimensionality and aquifer heterogeneities on surfactant-enhanced dissolution
for both small and large scales. This paper presents the results from one- and
two-dimensional surfactant-enhanced dissolution experiments. Mass transfer rate
coefficient dependencies on porous media properties, Reynolds number, and NAPL
saturation were determined for small column experiments. These results were
compared with experiments conducted in a small two-dimensional dissolution cell
and a pilot scale flume. Comparisons focused on the key parameters obtained from
small experiments that are needed in modeling large scale behavior of
surfactant-enhanced dissolution in heterogeneous porous media.

Key words: ground water, nonaqueous phase liquids, surfactants, dissolution,
up-scaling.

Oral presentation in organic contaminants session.

Barriers and Transport · Coronado Room

65 • CONTAINMENT OF HEAVY METAL AND CHLORINATED ORGANIC
SOLVENT CONTAMINATION USING SUBSURFACE BIOBARRIERS

G.A. James1, B.K. Warwood1, K. Horrigan1, R.
Hiebert2, A.B. Cunningham1, and J.W.
Costerton1, 1Center for Biofilm Engineering, Montana State
University, Bozeman, MT, 59717, and 2MSE, Inc., P.O. Box 4078, Butte,
MT, 59702

The use of biobarriers, formed in situ by microbial biomass and
extracellular products, to retard the migration of ground water contaminants was
examined using sand-packed columns and pilot-scale Iysimeters. Biobarrier
formation was accomplished by injection of a starved bacterial inoculum,
followed by nutrient stimulation. Exposure of biobarriers established in columns
to relevant concentrations of heavy metals (1 ppm strontium or cesium) or a
chlorinated organic solvent (50-300 ppm carbon tetrachloride) did not have a
deleterious effect on biobarrier integrity. The presence of microbial barriers
reduced contaminant flux by 96-99%. Pilot scale Iysimeters were designed and
manufactured to facilitate evaluation of biobarrier performance in a
two-dimensional configuration. Injection ports for nutrient and bacterial
addition were downstream from a constant head hydraulic flow reservoir. The
hydraulic flow simulated ground water flow through a contaminated subsurface
formation, while the injection ports simulated wells drilled down-gradient from
a contaminated site. Lysimeter characterization studies using chloride tracers
revealed flow heterogeneities (i.e., channeling), indicating simulation
of a three-dimensional flow configuration. Following injection of starved
bacteria and nutrient resuscitation, a consistent flow reduction of 90 to
>99% was achieved over a 60 day period. Biobarriers formed in the Iysimeters
have shown no ill effects due to the continuous presence of 1 ppm strontium.
These results suggest the use of microbial barriers is a feasible technology for
the containment of ground water contaminants. Furthermore, biological
containment has the potential to be linked to contaminant biosequestration or
biodegradation.

Key words: biobarrier, ground water ultramicrobacteria, bioremediation.

Oral presentation in barriers and transport session.

66 • BIOFILM BARRIERS IN SOIL

M. Dennis1, J.P. Turner1, J. Chase2, L.A.
Bulla2, and Y.A. Osman2, 1Department of Civil
& Architectural Engineering, University of Wyoming, Box 3295 University
Station, Laramie, WY, 82071, and 2Department of Molecular Biology,
University of Wyoming, Box 3354 University Station, Laramie, WY, 82071

A study was conducted to evaluate the feasibility of creating
low-permeability waste containment barriers using soil treated with bacteria and
appropriate nutrients to create a plugging biofilm. The study consisted of
bench-scale laboratory tests to evaluate changes in soil hydraulic conductivity
caused by the formation of biofilms. Sandy soils with initial hydraulic
conductivities ranging from 10-5 cm/sec to 10-3 cm/sec
were tested to determine whether a biofilm could be formed by the addition of
bacteria and nutrient solution and, if so, to measure changes in hydraulic
conductivity. Saturated hydraulic conductivities (ksat) were
measured using a flexible wall permeameter. Bacteria were mixed with the soil,
followed by soil compaction to maximum dry density at optimum moisture content.
The compacted specimen was then placed in a permeameter cell and permeated with
a nutrient solution. Hydraulic conductivity measurements were made at various
time intervals. Several bacterial strains were evaluated, including
Klebsiella pneumoniae, Beijerinckia lacticogenes, and
Beijerinckia indica. Significant reductions in ksat,
over several orders of magnitude, were observed for all bacterial strains.
Initial hydraulic conductivity of the soil strongly influences the degree of
plugging. Results of this study demonstrate that biofilm barriers may be a
feasible technology for waste containment in soils with hydraulic conductivities
one to two orders of magnitude greater than the EPA regulatory definition of
"low permeability," which is 10-7 cm/sec. Further research is
necessary to evaluate biofilm barriers at a scale that is more representative of
field conditions. Experience gained during this study has contributed to our
knowledge of laboratory procedures required for testing soils treated with
bacteria and nutrient solutions. For example, the traditional use of filter
paper at the ends of hydraulic conductivity specimens treated with
biofilm-producing bacteria results in extensive plugging of the filter paper,
followed by plugging of the soil, which will not necessarily occur if the filter
paper is not present. These and other experimental aspects of this study are
presented and discussed.

Key words: biofilm, hydraulic conductivity, barriers, waste containment.

Oral presentation in barriers and transport session.

67 • THE EFFECT OF ULTRA PURE WATER FLUSHING ON BACTERIAL
TRANSPORT IN NATURAL SEDIMENTS

T.A. Camesano and B.E. Logan, Department of Chemical and Environmental
Engineering, The University of Arizona, Tucson, AZ, 85721

New methods of aquifer biorestoration may require the injection of microbes
with the capability to degrade specific subsurface pollutants. Such schemes can
only be effective, however, if methods are developed to increase bacterial
transport over large distances, since bacteria will move only a few centimeters
to a meter in an aquifer without assistance. One way to enhance transport is by
increasing the electrostatic repulsive layer between the bacteria and the soil
particles. Flushing the column with ultra pure water (very low ionic strength)
will increase the electrostatic repulsive layer between the bacteria and the
soil surface and reduce the frequency of attachment. Previous experiments using
ultra-clean glass beads and quartz had shown that low ionic strength water could
increase bacterial transport under these conditions. Using a filtration
equation, we empirically determined a collision efficiency, a, for the bacteria
in our columns, with a defined as the ratio of bacteria sticking to the soil
grains to bacteria hitting the sediment. A significant decrease in a for
bacteria injected into the columns was seen when columns were flushed with ultra
pure water as compared to columns flushed with only artificial ground water. The
collision efficiency decreased from 2.31 x 10-2 (for AGW) to 4.74 x
10-3 (for ultra pure water), as shown below for a 7-cm column. An a
less than 10-3 will permit bacteria to travel further than 10 m in a
typical aquifer. Ultra pure water flushing appears to be an effective way of
mobilizing biocolloids. This could be of great benefit as a remediation
technique, since low ionic strength water is easily obtained and not hazardous
to the subsurface environment. Effect of Ultra Pure Water Flushing on Bacterial
Retention

Key words: bacteria, biocolloid, filtration, transport.

Oral presentation in barriers and transport session.

68 • INCREASING THE DIVERSION LENGTH OF CAPILLARY
BARRIERS

R.E. Pease and J.C. Stormont, Civil Engineering Department, University of New
Mexico, Albuquerque, NM, 87131

The diversion length of a capillary barrier is increased with the
introduction of a well-sorted sand layer immediately above the fine/coarse
interface. Various soils were evaluated as "transport layer" materials using
numerical simulation. Infiltration and evapotranspiration were simulated for one
year of an Albuquerque, NM, climate. The infiltration and evapotranspiration
varied daily in the simulations with the use of a daily effective flux. The
baseline simulation without a transport layer diverted moisture 5 m. The
diversion length was increased to 37 m with the use of a construction sand
layer, and a layer of 100-mesh sand did not allow any moisture to penetrate the
barrier. The simulation results are consistent with the field test results of
Stormont (Stormont, J.C., 1995. The performance of two capillary barriers during
constant infiltration. Submitted to Annual ASCE Convention, San Diego, CA, 1995,
October, 1995), which indicate an increase of capillary barrier diversion length
with the introduction of a sand transport layer. A capillary barrier may be an
inexpensive and stable alternative or addition to conventional cover systems for
semi-arid regions.

Key words: capillary barrier, diversion length, landfill cover, numerical
simulation.

Oral presentation in barriers and transport session.

Program Three Wednesday, May 22, 1996 Modeling and Transport · Coronado Room

69 • STOCHASTIC MODELING OF SOLUTE TRANSPORT IN A FRACTURED
MEDIUM

M.J. Butler, V.R. Schaefer, and J.C. Tracy, Northern Great Plains Water
Resources Research Center, South Dakota State University, Brookings, SD,
57007

A field study was conducted at the Sioux Falls, South Dakota, Runge Landfill
to determine the effects of fractures on the hydraulic conductivity and solute
transport potential of glacial till deposits. An infiltration trench system was
constructed at the Runge site during the summer of 1993. Chloride tracer was
injected into the trench system during the summer of 1995. Several wells within
the trench system were periodically sampled providing information on the
transport of the tracer. In addition, to compute the bulk hydraulic conductivity
at the site, slug tests were conducted at each sampling well using the Hvorslev
and Bouwer-Rice analysis methods. Estimates of the hydraulic conductivity and
the results of the tracer study are then used to calibrate both deterministic
and stochastic transport models. Model results are analyzed to determine which
approach produces more reliable predictions of solute transport in a fractured
clay till.

Key words: landfill, clay till, fractured media, stochastic transport.

Oral presentation in modeling and transport session.

70 • MODELING FATE AND TRANSPORT OF ATRAZINE IN THE
SATURATED-UNSATURATED ZONE OF SOIL

P.K. Allepalli and R.S. Govindaraju, Department of Civil Engineering, 119
Seaton Hall, Kansas State University, Manhattan, KS, 66506

Atrazine (2-chloro-4-ethylamino-6-isopropylamine-s-triazine) is a widely used
herbicide for selective control of broadleaf and grassy weeds, and has been
detected in ground water. Experimental work in this area shows that the
degradation of atrazine is dependent on the soil water content. Of specific
interest to this study is the influence of fluctuating water tables on atrazine
degradation. A 1-D finite-difference model has been developed to study
saturated-unsaturated water movement and transport of atrazine with
kinetic-nonlinear adsorption and water content-dependent degradation. The water
movement and chemical transport have been decoupled, such that water fluxes are
treated as being independent of the chemical concentrations. Model results of
the fate and transport of atrazine for various physical scenarios will be
presented.

Key words: atrazine, modeling, saturated-unsaturated, degradation.

Oral presentation in modeling and transport session.

71 • FIELD VALIDATION OF THE BACKWARD-IN-TIME ADVECTION
DISPERSION THEORY

J.L. Wilson1 and J. Liu2, 1Department of
Earth and Environmental Science, New Mexico Institute of Mining and Technology,
Socorro, NM, and 2Environmental Systems and Technology, Inc.,
Blacksburg, VA

We have recently developed a theory that can be used to locate the source of
contamination captured by a pumping well. Accounting for advection, dispersion,
linear-equilibrium sorption, aquifer heterogeneity, and regional natural
recharge, the theory is based on the concept of travel time probability. This
probability describes the time for a particle to travel from a source location
to the pumping well, and can be directly computed by solving partial
differential equations backwards-in-time, with a third type probability boundary
condition at the pumping well. We apply a two-dimensional version of the theory,
implemented numerically using the Laplace Transform Galerkin method, to the
analysis of a recent tracer test conducted at the Borden Site, in Ontario,
Canada (Linderfelt and Wilson, 1994). The test was designed to validate common
conceptual models of pumping well capture zones. Tracers were injected at 15
locations upgradient of a pumping well. Their arrival in the well was observed
with weekly concentration measurements. A single two-dimensional
backward-in-time simulation was used to predict separate travel time
probabilities for each injection site. These were compared to normalized
experimental breakthrough curves, and arriving tracer mass was assigned to 11 of
the injection locations. Tracer from four injection sites was predicted to miss
the pumping well. The assignments of mass and source location, and the predicted
tracer recovery, compare favorably with independent interpretations of the
experiment which were based on multiple three-dimensional forward simulations
(Linderfelt, 1994). Satisfactory performance of the method on the field test
data supports its validation as a standard tool, and demonstrates its practical
use.

Key words: backward-in-time simulation, advection dispersion, travel time
probability.

Oral presentation in modeling and transport session.

Nonaqueous Phase Liquids · Coronado Room

72 • DIMENSIONALITY AND HETEROGENEOUS EFFECTS ON ENHANCED
LNAPL RECOVERY USING HOT WATER FLOODING

K.O. Pytte and T.H. Illangasekare, Department of Civil, Environmental, and
Architectural Engineering, University of Colorado at Boulder, Boulder, CO,
80309

Thermal processes, such as hot water flooding and steam injection, have
essentially been used exclusively by the petroleum industry as a means of
enhanced oil recovery (EOR) from petroleum reservoirs. Similar techniques also
show promise as a remediation technique for the recovery of nonaqueous phase
liquids (NAPLs) from contaminated soils in the subsurface. Previous laboratory
studies have shown that an increase in temperature tends to markedly increase
the mobilization and direct recovery of contaminants from soil samples. However,
these studies have dealt only with one-dimensional, homogeneous systems or
confined petroleum reservoirs. To determine the applicability of these
techniques to unconfined aquifer remediation, heterogeneous and scaling issues
have to be addressed. The objective of this research is to determine the
effectiveness and feasibility of using hot water flooding to recover entrapped
NAPLs under micro- and macroscale saturations at various scales and system
complexities. The use of water flooding as a delivery mechanism for other
remediation techniques was also investigated. This paper presents the results
from NAPL mobilization experiments using various scales of interest. Using a
vacuum pump oil as a lighter-than-water contaminant, the recovery efficiencies
of various temperature hot water floods in homogeneous and heterogeneous systems
were determined for soil column, small two-dimensional, and pilot-scale
experiments. These efficiencies were compared to determine the practicality of
this remediation technique in more realistic multi-dimensional and heterogeneous
field systems. The flow paths of the hot water were also monitored to determine
the usefulness of hot water flooding as a delivery mechanism for the different
systems. In addition, theoretical analysis and modeling tools were used in an
attempt to understand the scaling issues involved in the field implementation of
this recovery scheme.

Key words: ground water, nonaqueous phase liquids, remediation,
thermally-enhanced recovery, up-scaling.

Oral presentation in nonaqueous phase liquids session.

73 • FATE AND TRANSPORT OF RESIDUAL NAPLS UNDER FLUCTUATING
WATER TABLE CONDITIONS

W. Han, L.N. Reddi, and M.K. Banks, Department of Civil Engineering, Seaton
Hall, Kansas State University, Manhattan, KS, 66506

A mathematical model will be presented to simulate the fate and transport of
lighter-than-water NAPLs (LNAPLs) both in saturated and vadose zones. LNAPLs
usually stay above the water table and form large, continuous pools. As the
water table fluctuates due to seasonal recharge and water pumping, a smear zone
is formed as a result of LNAPL entrapment both below the water table and in the
vadose zone. Characterization of the behavior of the LNAPLs in these two areas
includes their transportation, volatilization, dissolution, and biodegradation.
It is assumed that the movement of the water table with the LNAPL pool maintains
a constant speed, and the range of the movement remains the same all the time.
Equilibrium conditions are assumed to be reached before successive fluctuation
of the water table. The movement of the pool recharges the ganglia which have
been depleted by volatilization in the vadose zone, and by dissolution and
biodegradation in the saturated zone. The size of ganglia is represented by a
set of effective diameters. In the vadose zone, the Hamaker method is applied to
calculate the mass loss of ganglia through volatilization and the change of
their size distribution with time. An advection-dispersion equation which is
modified to include ganglia dissolution and biodegradation is used to simulate
the time-dependent process in 2-D saturated zone, where a constant rate of 1-D
water flow is maintained. The mass loss of both ganglia and pools within the
saturated zone is calculated . Through the model, it is possible to predict the
ganglia size distribution both in the vadose and saturated zones before and
after the water table movement, and the life time of LNAPLs.

Key words: dissolution, volatilization, lighter-than-water nonaqueous phase
liquid ganglia, lighter-than-water nonaqueous phase liquid pool.

Oral presentation in nonaqueous phase liquids session.

74 • DNAPL MIGRATION IN A COMPLEX MULTI-AQUIFER SYSTEM

D.B. Stephens1, J.A. Kelsey1, M.A.
Prieksat1, M.G. Piepho1, M.D. Ankeny1, and C.
Shan2, 1Daniel B. Stephens & Associates, Inc., 6020
Academy Road N.E., Suite 100, Albuquerque, NM, 87109, and 2Lawrence
Berkeley Laboratory, Mail Stop 505, Berkeley, CA, 94720

A laboratory experiment was conducted to demonstrate the behavior of DNAPL
(1,1,1-trichloroethane) in a complex aquifer system. The system simulated
consists of two unconfined aquifers separated by a low permeable bedrock
perching layer that contains a fracture. In contrast to previous work by other
researchers of DNAPL migration in hydrostatic conditions, in this experiment,
prior to and during the DNAPL release, ground water flow occurs from the upper
to lower aquifer via the fracture. Although the experiment illustrates that
DNAPL may migrate rapidly in narrow pathways, the observations were predicted
rather well by a simplified analytical solution and a numerical simulation with
the multi-phase flow and transport code TOUGH-2. With recharge to the lower
aquifer occurring through the fracture, a DNAPL pool did not develop prior to
its entry into the fracture.

Key words: nonaqueous phase liquids, transport modeling.

Oral presentation in nonaqueous phase liquids session.

Contaminant Fate and Transport · Coronado Room

75 • BENCH-SCALE INVESTIGATIONS ON VIBRATORY MOBILIZATION OF
IMMISCIBLE LIQUID GANGLIA

L.N. Reddi, J. Nichols, and H. Wu, Department of Civil Engineering, Seaton
Hall, Kansas State University, Manhattan, KS, 66506

The feasibility of vibratory mobilization of residual LNAPL (nonaqueous phase
liquid lighter-than-water) ganglia was well established in previous studies by
the principal author. In this presentation, results from bench-scale experiments
will be reported to provide a practical understanding of the technology. The
experiments were conducted using a probe-type vibrator to evaluate the changes
in relative density of the soil-NAPL medium and the distribution of ganglia in
the vibrated zone. In some experiments, the probe-type vibrator was housed in a
'vibroflot' to integrate the pumping mechanism and thereby to simulate the field
implementation process. It was shown that the distribution of ganglia in the
vibrated zone was governed not only by the relative density variation but also
by the uniformity of flow gradients. Non-uniform flow rates in the zone around
the vibroflot was shown to result in clean-up of some areas and in accumulation
of ganglia (exceeding initial residual volumes) in other areas. The results from
the experiments supported an integrated approach where the vibrator was
augmented with a pumping mechanism yielding uniform and predictable flow
gradients in the vibrated zone.

Key words: relative density, vibrations, lighter-than-water nonaqueous phase
liquid ganglia.

Oral presentation in contaminant fate and transport session.

76 • THE BINDING OF ORGANIC CONTAMINANTS TO HUMIN

S.D. Kohl and J.A. Rice, Department of Chemistry & Biochemistry, South
Dakota State University, Brookings, SD, 57007-0896

It has been recognized for some time that a significant fraction of most
organic contaminants that are introduced into a soil or sediment become rapidly
and irreversibly bound to humin fraction of naturally-occurring organic matter.
The insolubility of humin in essentially any solvent has made the study of these
"bound residues" difficult. The ability to fractionate humin into four
components (extractable lipids, bound-humic acid, bound lipids, and mineral
matter) using the methyl-isobutylketone partitioning procedure is providing new
insights into the phenomenon of bound residue formation and the fate of
anthropogenic organic compounds in neutral environments. Results will be
presented describing the formation of bound residues in humin for a variety of
anthropogenic organic compounds including atrazine, 2,4-D, DDT, PCBs, and PAHs
from studies using 14C-labeled compounds. The distribution of the
radioactivity among the components of humin will be compared and contrasted.
Potential binding mechanisms will be discussed.

Key words: humin, bound residue, 2,4-D, atrazine, DDT, polycyclic aromatic
hydrocarbons, polychlorinated biphenyls.

Oral presentation in contaminant fate and transport session.

77 • CONTAMINATED SOIL RECOVERY RATE OF A LEACHER COLLECTION
SYSTEM

D.L. Rainey and P.-C. Yuan, Department of Technology & Industrial Arts,
Jackson State University, Jackson, MS, 39217

Leachate is defined as any liquid, including any suspended components in the
liquid, that has seeped, drained, or percolated through a collection system.
Within the past few decades leachate collection systems have become valuable
tools to scientists in the field of Environmental Engineering. Vertical column
tests have caused collection systems to become even more advanced. They are used
by researchers to serve in such capacities as laboratory models for simulating
different types of transport in porous media.

These two experiments consisted of: 1. various tests to study the column
contact time and superficial velocity of water, and 2. percolation of the tracer
element, Benzoic Acid, through a sand-compacted column.

An interchangeable vertical column was constructed of piping material to
serve as the testing apparatus. In the first phase, a measure of the column
contact time and superficial velocity were attained by pouring one or two liters
of water down the column and taking time measurements at different levels. In
the second experiment two hundred milliliters of Benzoic Acid and one or two
liters of water, depending on the size of the column, were poured down the
column. Samples were then taken at designated levels. The test samples were then
titrated to measure the amount of base it would take to neutralize the acid.

Key words: leachate, contaminated soil, recovery, reclamation, percolation.

Oral presentation in contaminant fate and transport session.

PCBs and Mohawk Nation Superfund Site · Coronado Room

78 • AN OVERVIEW OF SUPERFUND BASIC RESEARCH OF PCB POLLUTION
OF THE MOHAWK NATION

B. Bush1,2, A.C. Casey1, E. Fitzgerald1, and
K. Jock3, 1School of Public Health, State University of
New York at Albany, Wadsworth Center, New York State Department of Health,
Albany, NY, 12201-0509, 2e-mail: bbush@wadsworth. ph.albany.edu, and
3Environmental Division, St. Regis Mohawk Tribe, Hogansburg NY, 13655

There are four major sources of pollution near the power dam on the St.
Lawrence River between Cornwall, Ontario, and Massena, NY. The Akwesasne Mohawk
Nation straddles one international border between Canada and the United States
and also three borders between Ontario, Quebec, and NY State, so that a total of
five non-Mohawk governments are working with the Mohawks. One of the great
challenges of this project has been learning, and teaching students, to work
with an environmental task force drawn from the whole Mohawk Nation.

Ultra-trace congener-specific PCB analysis by gas chromatography with
electron capture detection has allowed new important sources of PCB to be
delineated. These have been plotted on a geographical information system
(Mapinfo) so that contamination of water, sediment, soil, vegetables, fish, and
seasonally-variable air pollution may be related to observed contamination of
the blood and breast milk of Mohawks.

In 1995, contaminated river sediment bordering the General Motors foundry was
dredged and dumped on land. Problems encountered, solved, and produced by this
action will be discussed.

Key words: polychlorinated biphenyls, minority population, remediation.

Oral presentation in PCBs and Mohawk Nation Superfund site session.

79 • PHOTOCATALYTIC DEGRADATION OF PCBs IN AQUEOUS
TiO2 SUSPENSIONS

C.S. Hong, Y. Wang, I.W. Huang, and B. Bush, School of Public Health, State
University of New York at Albany, Wadsworth Center, New York State Department of
Health, Albany, NY, 12201-0509

A generator-column technique was used to prepare aqueous solutions of PCBs.
The degradation of 2-chlorobiphenyl (2-CB), Aroclor 1248, Aroclor mixture (1221,
1016, 1254, and 1260), and St. Lawrence River water by simulated sunlight or
sunlight has been investigated in the presence of aqueous suspensions of
TiO2. The effect of pH, TiO2 concentration, humic acid,
initial PCB concentration, and added oxidants (H2O2,
KIO4, K2S2O8, and NaClO) have been
studied. Biphenyl-2-ol, monochlorophenyl phenols, 2-chlorobenzaldehyde,
2-chloroacetophenone, benzoic acid, and 2-chlorobenzoic acid were formed as the
principal intermediates. Formate and acetate were formed as products during the
latter stages of photooxidation. The kinetics of the disappearance of
2-chlorobiphenyl, formation and decomposition of intermediates, and
CO2 evolution were also investigated. The degradation of 2-CB
followed pseudo-first order kinetics. The photocatalytic pathway of 2-CB is
likely to involve an attack of OH radicals on the phenyl ring. After addition of
OH radicals to the aromatic ring, the ring opens, and CO2 is
ultimately evolved via many oxidation steps. Complete mineralization of 2-CB to
CO2 was observed with the addition of H2O2.

Key words: photocatalysis, polychlorinated biphenyls, TiO2,
remediation.

Oral presentation in PCBs and Mohawk Nation Superfund site session.

80 • SUPERCRITICAL FLUID TECHNOLOGY FOR PCB/PAH-CONTAMINATED
SOIL REMEDIATION

L.L. Tavlarides, P. Chen, W. Zheu, J. Zhang, and G. Anitescu, Chemical
Engineering and Material Sciences Department, Syracuse University, Syracuse, NY,
13244

A supercritical fluid process to remediate PCB- and PCB/PAH-contaminated
soils/sediments consisting of supercritical CO2-cosolvent extraction
followed by supercritical water oxidation (SCWO) of the soil/sediment extract is
proposed. Supportive studies include laboratory scale extractions, laboratory
scale water oxidations, and bench scale extractions. Surrogate laboratory spiked
samples and native contaminated St. Lawrence and Hudson River sediments have
been investigated. SCWO experiments with 4-monochlorobiphenyl/methanol are in
progress to determine destruction efficiencies and reaction kinetics. Solubility
studies are also in progress for SC-W2/cosolvent-PAH systems to
define suitable systems for PAH and PCB extractions. The proposed process,
conditions of operation, and current results will be discussed.

Key words: supercritical, polychlorinated biphenyls, polycyclic aromatic
hydrocarbons.

Oral presentation in PCBs and Mohawk Nation Superfund site session.

81 • APPLICATION OF REMEDIAL TECHNOLOGIES AT THE MOHAWK
NATION SUPERFUND SITE

R.J. Scrudato, Environmental Research Center, Room 319, Piez Hall, SUNY at
Oswego, Oswego, NY, 13126

A summary of the remedial technologies being used and considered for the
General Motors National Priority List site located near Massena, NY, will be
discussed in light of PCB/sediment partitioning, volatility, solubility, and
anaerobic biodegradability. The majority of the PCBs associated with the Massena
area sediments are concentrated in the finer grained, organic fractions. On
drying at ambient temperatures, these sediments lose up to 25% of the total PCB
concentration through volatilization, and volatile losses correlate well with
dehydration of the sediments. Advanced oxidative processes (AOP) including
photodegradation and an electrochemical peroxidation have been used to degrade
more than 90% of the PCBs in sediment slurries. AOP destruction correlates with
PCB solubility as evidenced by relative congener susceptibility to degradation.
Although it is evident that PCB-contaminated sediments collected from the
Massena area have experienced anaerobic degradation, this process is slow and
limited.

Key words: remediation, bioremediation, polychlorinated biphenyls,
electrochemical.

Oral presentation in PCBs and Mohawk Nation Superfund site session.

Program Three Thursday, May 23, 1996 Risk Assessment · Coronado Room

82 • DEVELOPMENT & IMPLEMENTATION OF A HIGH MOUNTAIN
DESERT ECOLOGICAL RISK ASSESSMENT

M.E. Maly1 and C. Marsh2, 1U.S. Army
Environmental Center, ATTN: SFIM-AEC-IRB, Aberdeen, MD, 21010-5401, and
2Rust Environment & Infrastructure, 743 Horizon Court, Grand
Junction, CO, 81506

In compliance with both the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) and the Resource Conservation and
Recovery Act (RCRA), an installation-wide Ecological Risk Assessment (ERA) was
developed, planned, and implemented at the Tooele Army Depot in central Utah.
Tooele's installation restoration program is conducted under both CERCLA and
RCRA due to its National Priorities Listing and the issuance of a RCRA
Corrective Action Permit by the State of Utah. Both laws require that clean-ups
be protective of both human health and the environment.

Tooele's unique high western, semi-arid climate and predominantly terrestrial
ecosystem had to be carefully molded into a conceptual plan for implementation
of the ERA. At the start of the project in 1993, very little regulatory guidance
and no Army guidance was available to help scope the study which was to evaluate
the risk posed by 54 sites under investigation at the 24,732 acre facility. The
Army worked closely with the U.S. Environmental Protection Agency Region VIII
Ecological Technical Assistance Group (ETAG) to determine the proper approach
and depth of study.

This paper describes the unique Tooele environment which had to be taken into
consideration during the planning process, the partnering with the regulators to
achieve an approved work plan, the ERA's scope, and the resulting findings,
conclusions, and recommendations. In particular, the talk will focus on how the
assessment and measurement endpoints were selected after review of the site
ecology, including consideration of major food chains, key species, and
potentially-occurring threatened and endangered species.

Key words: ecological risk assessment, installation restoration.

Oral presentation in risk assessment session.

83 • ESTROGENIC AND PROGESTAGENIC SCREENING OF POLLUTANTS
IN VITRO USING ENDOMETRIAL AND BREAST CANCER CELL LINES

J. Garey and M.S. Wolff, Department of Obstetrics, Gynecology, and
Reproductive Science and Department of Community Medicine, Mt. Sinai School of
Medicine, New York, NY, 10019

A variety of waste products commonly found as contaminants of waterways have
been discovered to act as sex hormone analogues. In this investigation we have
analyzed organochlorines, trace elements, plasticizers, and PCB congeners for
estrogenic or antiestrogenic and progestagenic or antiprogestagenic activities
using in vitro screening. The endometrial cancer cell line, Ishikawa
Var-1 (estrogenic), and the breast cancer cell line, T47D (progestagenic),
enabled us to detect hormonal activity with increased production of alkaline
phosphatase as a colorimetric endpoint. Estrogenic activity was detected among
many compounds, including the organochlorines kepone, 1-hydroxychlordene,
endosulphan, and o,p'-DDT, and the plasticizer bisphenol A. Confirmation
of hormonal activity was achieved through the addition of a pure antihormone to
the test substances. To date, no antiestrogenic, progestagenic, or
antiprogestagenic activities have been detected among contaminants tested.
Ultimately, these screening systems will be used to evaluate sediment extracts
from the Hudson River bight. We hope to predict hormonal activity of typical
pollutant mixtures and thus provide useful information for remediation efforts.

Key words: hormonal activity, organochlorines, plasticizers, polychlorinated
biphenyls.

Oral presentation in risk assessment session.

84 • UPTAKE OF TRICHLOROETHYLENE BY EDIBLE GARDEN PLANTS

W. Schnabel, A. Dietz, J. Burken, J.L. Schnoor, and P.J.J. Alvarez,
Department of Civil and Environmental Engineering, University of Iowa, Iowa
City, IA, 52242-1527

Edible garden plants (carrots, spinach, and tomatoes) were grown to maturity
inside continuous air-flow bioreactors, and were regularly irrigated with
synthetic ground water containing 14C-labeled TCE at two dose levels
(approximately 560 mg/l for high dose and 140 mg/l for low dose reactors).
Following TCE exposure for 31 to 106 days, different plant tissues and
bioreactor compartments were analyzed for the 14C label. Samples were
analyzed by combustion with a Biological Oxidizer followed by liquid
scintillation counting. Samples were also analyzed for total TCE and for the
potential presence of TCE metabolites using Purge & Trap Gas Chromatography.
Both aerobic and anaerobic potential transformation products were included in
the analysis. Radiolabel recoveries ranged from about 50% for low-dose reactors
to about 70% for high-dose reactors. Most of the recovered 14C label
volatilized (74% to 95%) and was found in the OrboR tubes that were
used to capture the air exiting the reactors. A portion of the recovered label
(5%-25%) was found sorbed to the soil. Although the percentage of the recovered
14C label found in plant material was relatively small (1% to 2%),
the concentration of 14C label in edible plant tissue was higher than
in the surrounding soil. On a wet weight basis, accumulation factors (TCE
concentration in edible tissue divided by TCE concentration in surrounding soil)
ranged from 2.6 in the high dose tomato reactors to 32 in the low dose spinach
reactors. If the radiolabel found by combustion of plants were TCE, the
concentrations in edible tissue would range from 152 ppb for the high-dosed
tomatoes to 580 ppb for the high-dosed spinach. However, neither TCE nor its
commonly reported transformation products were detected by Purge & Trap
GC-MS. Furthermore, the 14C label found in plant tissue could not be
extracted into the organic solvent CS2 or into the inorganic solvent
10N H2SO4. This suggests that TCE was taken up,
transformed, and bound to the plant material. Further research into the
chemistry and toxicology of this bound residue would provide insight into the
health effects associated with consumption of TCE-exposed plants. Research in
this area could also forward the use of phytoremediation as a viable alternative
for the clean up of TCE spills.

Key words: phytoremediation, vegetative uptake, bound residue.

Oral presentation in risk assessment session.

85 • CREATION OF THE ARMY'S BIOLOGICAL TECHNICAL ASSISTANCE
GROUP: A HELP GROUP FOR ECOLOGICAL RISK ASSESSMENTS

M.E. Maly, U.S. Army Environmental Center, ATTN: SFIM-AEC-IRB, Aberdeen
Proving Ground, MD, 21010-5401

To assist Army environmental project managers cope with new and complex
issues surrounding Ecological Risk Assessments (ERAs), the U.S. Army
Environmental Center (USAEC), in cooporation with several other Army
organizations, established a Biological Technical Assistance Group (BTAG). The
Army saw the need for a BTAG because the importance of ERAs had greatly
increased over the last few years in clean-up programs being conducted under
both CERCLA and RCRA Corrective Action.

Unlike the human health risk assessment, for which numerous guidance
documents were available to help project managers focus on protecting human
health, neither the regulatory agencies nor the Army had published much specific
guidance on conducting ERAs back in the early to mid-1990's. In 1990, the EPA
established BTAGs at each of their ten regional offices to help their remedial
project managers cope with this quickly evolving requirement. In 1993, the USAEC
recognized the Army's need for a similar assistance group and began organizing
the Army's own BTAG. The Army BTAG has now been operating for two years, meeting
on a monthly basis to assist restoration project personnel at both active and
closing installations.

This paper will follow the creation of the BTAG in 1993, outline how the
group functions and describe where the BTAG hopes to be in the years to come.
Specific examples will be provided describing how the BTAG has assisted Army
project personnel at numerous installations across the country.

Key words: ecological risk assessment, Army, restoration.

Oral presentation in risk assessment session.

86 • PERCEPTIONS OF ENVIRONMENTAL RISK IN THREE COMMUNITIES
OF EL PASO, TEXAS

T. Byrd and J. VanDerslice, University of Texas-Houston School of Public
Health at El Paso, 901 Education Bldg., UTEP, El Paso, TX, 79968

Perceptions of environmental risk were explored in three communities of El
Paso, Texas, through a series of focus groups and a door-to-door survey of 300
residents. Included in the survey were questions about a) knowledge of
environmental risks and the perceived level of risk, b) sources of information
and source credibility, and c) general attitudes about risk, locus of control,
and the government's ability to protect the population. The three communities,
each of different SES, were compared for differences in risk perceptions,
knowledge, and attitudes. In general, many respondents had no knowledge of many
of the environmental risks mentioned. Perceived risk to self and family was
consistently lower than perceived risk to the community as a whole, especially
for risks that might be considered behavioral in nature. Surprisingly, only a
small proportion of respondents were even aware of local and national
environmental agencies. The media was by far the most common source of
environmental risk information. These results demonstrate a clear need for
improved environmental risk communication along the U.S.-Mexico border.

Key words: risk perception, risk communication, U.S.-Mexico border.

Oral presentation in risk assessment session.

87 • ARSENIC RISK AND REGULATION

B.P. Sullivan, Los Alamos Technical Associates Inc., 2400 Louisiana Blvd.
N.E., Suite Building 1, Suite 400, Albuquerque, NM, 87110

On the basis of carcinogenic potency estimates developed by EPA and its
prevalence in the environment relative to other natural and man-made
carcinogens, arsenic (As) can arguably be considered one of the most serious
environmental threats to human health. However, when considered across
regulatory programs and environmental media, environmental standards for As are
highly inconsistent in terms of levels of allowed risk. In particular, even
though EPA estimates suggest that as many as 64 million household residents in
the U.S. may be exposed to potentially health-threatening levels of arsenic in
drinking water, the federal Safe Drinking Water Act (SDWA) mandates a Maximum
Contaminant Level (MCL) for As that permits a carcinogenic risk level fully
1,000 times greater than that associated with the MCLs established for other
known human carcinogens. The anomalous manner in which As is regulated as an
environmental carcinogen can be directly attributed to its dual nature as a
naturally-occurring element and a widespread industrial contaminant. The MCL for
As is scheduled for reassessment, and depending on the outcome of that effort,
as many as 13,000 public water treatment systems could experience a significant
economic impact. This paper presents an overview of the scientific literature
concerning As toxicology, epidemiology, and water treatment technology that will
be considered by EPA during revision of the existing SDWA standard for As. The
manner in which the As MCL is revised may also affect how it is regulated in
other environmental media, as well as the way in which human health risks posed
by other environmental carcinogens are both perceived and regulated in the
future. These broader implications of the impending reassessment of
environmental As are also discussed.

Key words: arsenic, environmental risk, water treatment.

Oral presentation in risk assessment session.

Program Four Tuesday, May 21, 1996 Analytical Methods · Santa Fe Room

88 • A SIMPLE INEXPENSIVE ASSAY FOR TOXIC CHEMICALS USING A
BACTERIUM AS THE INDICATOR ORGANISM

J.L. Botsford1, T. Hillaker1, V. Homer2, M.
Gonzalez3, M. Benavidez3, F. Pacheco3, W.
Steen3, O. Lucero4, and M. Mathews4,
1Department of Biology, New Mexico State University, Las Cruces, NM,
88003, 2Fort Sumner High School, 3New Mexico State
University, and 4students, Gadsden High School and Las Cruces High
School

A simple test for toxic chemicals has been developed. The soil bacterium
Rhizobium meliloti is combined with the toxic chemical. A tetrazolium
dye, MTT (3-[4,5-Dimethylthiazol-2-yl]2,5-diphenyl-tetrazolium bromide) is
added. The bacterium can reduce this dye causing the optical absorbance to
increase dramatically. The increase can be determined with a simple
spectrophotometer. Toxic chemicals and minerals inhibit the reduction of the
dye. The assay has been compared with published results of tests using the
Microtoxä, a microbiological test for toxic compounds using a bioluminescent
marine bacterium. The assay offers another method to determine the toxicity of
compounds, a method that is simple, rapid, and inexpensive.

Key words: toxic chemicals, assay, student involvement, bioremediation.

Oral presentation in analytical methods session.

89 • FLUORESCENT SILICA COLLOIDS FOR STUDYING CONTAMINANT
TRANSPORT IN GROUND WATER

H.E. Nuttall1,2, D. Smith1, W. Whittenburg1,
and P. Reimus3, 1Department of Chemical and Nuclear
Engineering, University of New Mexico, Albuquerque, NM 87133,
2e-mail: [email-masked], and 3Los Alamos National
Laboratory

Understanding and quantifying the movement of contaminated ground water is an
important but currently very costly step in DOE's remediation programs. The use
of fluorescent dyed silica colloids to quantify ground water travel times and
major flow paths is a new and innovative contribution to hydrology. Silica
colloids are environmentally safe since most soils are composed primarily of
quarts (silica) and feldspars. When injected into a ground water system,
colloids will provide critical information on the maximum contaminant
velocities. Colloids unlike tracer solutes will travel primarily through the
major flow paths and be rejected from the smaller micro pores by both size and
charge exclusion. These properties cause colloids to travel at the rate of the
fastest moving contaminants.

In laboratory experiments, we showed that silica colloids migrate freely
through soils, quarts packing, core columns, and natural fractures. The very low
microsphere concentrations of fluorescent colloids were measured using a flow
cytometer as the analytical tool. In recent tests at Los Alamos National
Laboratory, colloids were shown to travel through fractures much faster than a
conservative tracer such as bromide. We have also modeled in 3D the transport of
colloids through natural fractures and compared the results to the experimental
data. We are currently planning field experiments using these unique fluorescent
silica colloids at an UMTRA site.

Key words: ground water, tracers, colloids, contaminate, soil.

Oral presentation in analytical methods session.

90 • MATERIAL CLASSIFICATION OF NONAQUEOUS PHASE LIQUID FROM
3D IMAGING DATA

H. Tahani1, R.L. Peyton2, S.H. Anderson2,
and C. Gantzer3, 1Campus Computing, 2Department
of Civil Engineering, and 3School of Natural Resources, University of
Missouri-Columbia, Columbia, MO, 65211

Volume visualization has emerged as a promising field in the study of
hazardous chemicals. Using a series of X-ray computed tomography (CT) images,
volume data were constructed for simulation of hazardous chemical transport in
heterogeneous soil cores. The volume data were also used to evaluate the spatial
distribution of nonaqueous phase liquid (NAPL) in sand. To display and/or
analyze the chemical concentration in the volume data, the images before the
injection of the chemical are subtracted from the images subsequent to the
injection of the chemical. At present, there has been no direct
classification of chemicals in a volume data.

Material classification is the key step in creating images from volume data.
Good classification techniques, based on properties of the objects and
characteristics of the CT images, not only create good visual effects for
displaying the volume data on the 2D computer screen, but also improve the
accuracy of the measurement of displayed objects. In this paper, a new
classification algorithm based on pattern recognition techniques is proposed for
displaying volume data for NAPL using a sequential series of CT images of a sand
core. As a result of this classification process, more accurate measurements,
evaluation, and analysis can be done.

Key words: nonaqueous phase liquids, CT imaging, volume data, classification.

Oral presentation in analytical methods session.

91 • DEVELOPMENT OF AN INSTRUMENTAL FRACTIONATION AND
QUANTITATION SCHEME FOR SELECTED POLYNUCLEAR AROMATIC HYDROCARBONS PRESENT IN
EXTRACTS FROM WOOD-PRESERVING WASTE

K. Washburn, H. Huebner, S. Safe, and K.C. Donnelly, Faculty of Toxicology,
Texas A&M University, College Station, TX, 77843-4463

The polynuclear aromatic hydrocarbons (PNAs) are components of
wood-preserving waste (WPW) which are known to contain multiple classes of
organic and inorganic compounds. PNAs remain potent environmental contaminants
because of their high carbon content and low vapor pressure which result in
stability.

Identification and quantitation of individual PNAs and classes of PNAs is a
preliminary step in a assessing risk and addressing potential remediation of
WPW. Ag+ from AgNO3 interacts with the conjugated P
electrons of PNAs, allowing for a chromatographic separation based on differing
degrees of conjugation. A high-volume, low-pressure (HVLP) chromatographic
system with a 2-meter, high-bore AgNO3/silica-packed column
(in-house) and a Waters 600 HPLC system in tandem with a tunable (200-800 nm)
photodiode-array detector (Waters 996) offers a comprehensive instrumental
package capable of separating PNAs by degree of aromaticity and identifying and
quantifying individual components.

The system described was used to separate and quantify 115 individual PNAs
from a complex WPW-extract. Sub-fractions collected included 2-ring, 3-ring,
4-ring, and 5- and >5-ring. This data can later be used to determine
potential interaction of PNAs by class and establish the contribution of each to
the toxicity of the whole. The data generated will allow comprehensive risk
assessment based on constituent PNAs. While the first separation was very
tedious, later separations can be tailored to collect specific fractions of
interest. This research is supported by NIEHS P42ESO4917.

Key words: polynuclear aromatic hydrocarbons, polycyclic aromatic
hydrocarbons, separation, detection.

Oral presentation in analytical methods session.

92 • DEVELOPMENT OF AN IN SITU INSTRUMENTATION BUNDLE
FOR MONITORING AIR INJECTION REMEDIATION TECHNOLOGIES

C.K. Baldwin, B.L. Hall, and R.R. Dupont, Utah Water Research Laboratory,
Utah State University, Logan, UT, 84322-8200

The advent of the use of air injection remediation technologies such as air
sparging and in-well aeration has highlighted a need for monitoring techniques
which allow evaluation of remediation mechanisms in the subsurface. With this
need in mind, an instrumentation bundle suitable for use in both the saturated
and vadose zones was developed for monitoring subsurface conditions during air
injection. The configuration and application of the bundle for real-time site
monitoring during active remediation is described. The bundle provides
information on dissolved oxygen and ground water displacement for use in
defining the volume of influence of air injection systems. Also available is
information on changes in hydrocarbon and oxygen concentrations and pressure
gradients in the vadose zone. Laboratory testing protocols used for sensor
evaluation are included along with results gathered during field testing of an
in situ air sparging system

Key words: air sparging, monitoring, remediation, in-well aeration, dissolved
oxygen.

Oral presentation in analytical methods session.

93 • ELECTROCHEMICAL SENSORS FOR REMOTE MONITORING OF
INORGANIC AND ORGANIC CONTAMINANTS

J. Wang1, N. Foster1, P. Farias1, J.
Lu1, D. Larson1, and K. Olsen2,
1Department of Chemistry and Biochemistry, New Mexico State
University, Las Cruces, NM, 88003, and 2Battelle PNL, Richland, WA,
99352

Submersible electrochemical sensors have been developed for remote monitoring
of inorganic and organic pollutants. Such in situ operation offers rapid
warning against sudden contamination and feedback during remediation activities.
The new device is based on a novel 3-electrode housing and connected to a 50-ft
long shielded cable (via environmentally-sealed connectors). Highly sensitive
potentiometric stripping analysis is employed for the detection of trace metals,
while amperometric biosensing at enzyme electrodes is used for monitoring
phenolic and peroxide contaminants. Field demonstrations will be discussed,
along with future prospects.

This work was supported by the U.S. DOE through the WERC program.

Key words: electrochemical sensors, remote monitoring, site characterization.

Oral presentation in analytical methods session.

94 • INFRARED PYROMETRY FOR WASTE CHARACTERIZATION

J.A. Macy, New Mexico State University, Department of Mechanical Engineering,
Box 30001, Department 3450, Las Cruces, NM, 88003-0001

The research presented shows the development and application of two numerical
methodologies for thermal waste characterization. A historical perspective of
hazardous and nuclear waste production and storage in the Department of Energy
complex is presented to provide motivation for thermal waste characterization.
Specifically, the Hanford plutonium production plant with its underground
storage tanks (USTs), containing hazardous and nuclear wastes, is examined. The
objective of the research is the development of a methodology by which heat
sources in the USTs can be remotely located and identified either for
remediation purposes or for robotic path planning. The methodology is used in
the broader context of the Multi-sensor Analysis Program for Environmental
Restoration (MAPER) project developed at New Mexico State University by Dr.
Edward Hensel. The MAPER analyses utilize data collected from many different
sensors as well as historical site information to fully characterize a waste
site in a hybrid fashion. A problem statement is established based upon the
restrictions of UST robotic capabilities and basic infrared (IR) pyrometer
operation. The two numerical methods are developed as ANSI C routines. One
routine is designed to provide real-time information to the robot operator about
the UST interior, while the other routine is designed to calculate an estimated
temperature distribution using a weighted least-squares methodology after a data
survey. The estimated temperature distribution provides a higher resolution
image of the UST surface, as compared to the measured temperature distribution,
so individual heat sources may be located. A mock UST designed by Sandia
National Laboratories and New Mexico State University was built to provide a
test bed for data collection. Many data surveys from the mock UST were collected
using a robotic arm and sensor head assembly. Two of the data sets are
graphically presented to show the positions of known heat sources and their
thermal responses. The results of the two analyses on the data sets are
graphically presented to illustrate the correlation between known heat sources
and estimated thermal targets. Based upon the correlation between the targets
and the known sources, it is easy to conclude that the IR analysis is capable of
locating and presenting bounding boxes for thermal objects in a underground
storage tank.

Key words: underground storage tank, infrared pyrometry, waste
characterization.

Oral presentation in analytical methods session.

95 • ATOMIC FORCE MICROSCOPY (AFM) IMAGING OF DESTRUCTIVE
ADSORBENT PARTICLE SURFACE MORPHOLOGY

I. Lagadic, S. Decker, T. Boronina, O. Koper, C. Mohs, and K.J. Klabunde,
Chemistry Department, Kansas State University, Manhattan, KS, 66506

Atomic Force Microscopy (AFM) experiments were carried out on both metal
oxide (CaO, MgO) and metal (zinc) particles used as destructive agents for
chlorocarbons such as CCl4. AFM provides information about the sample
surface morphology and enables us to compare this surface morphology before and
after reaction with CCl4.

For both CaO and MgO, two types of metal oxide nanoparticles were observed:
aerogel-prepared (AP) and conventionally-prepared (CP). The CP sample surface
shows large particles (~40 nm) slightly elongated in shape while AP sample
surface exhibits aggregates, varying in size from 60 to 100 nm, made up with
small spherical particles (~20 nm). After exposure to a low CCl4
pressure (10 torr) for 5 minutes at 450°C, the CP sample surface displays wide
flat areas, which are presumed to be CaCl2.2H2O layers,
while particles are still visible on AP sample surface allowing for further
reaction. CaO and MgO reactivities were also compared for CP samples. The
surface morphologies after CCl4 decomposition suggest that the active
sites involve the whole CP-CaO surface while they only involve the CP-MgO
particle edges. Transition metal oxide-coated MO (M = Ca, Mg) nanoparticles were
also investigated by AFM.

The AFM study of zinc particles shows a drastic surface morphology
modification after reaction with CCl4 in aqueous solution as the
tube-like zinc particles seem to be "eroded." This investigation is still
underway.

Key words: Atomic Force Microscopy (AFM), metal oxide, metal, chlorocarbon,
decomposition, destructive adsorption.

Oral presentation in analytical methods session.

96 • USE OF X-RAY ABSORPTION NEAR-EDGE STRUCTURE TO DETECT
BIOLOGICAL REDUCTION OF CHROMIUM(VI)

S.J. Rothenburger1, R.R. Chianelli2, M.
Modrick3, M. Sansone1, and B. DeVries1,
1Exxon Research and Engineering Co., Annadale, NJ, 08801,
2Chemistry Department, University of Texas at El Paso, El Paso, TX,
79968-5748, and 3Exxon Research and Engineering Co., Florham Park,
NJ, 07932

Metals contamination in soil and wastewater is a current problem at
refineries and other production sites. Bioremediation of metals using indigenous
microorganisms offers an in situ, low cost alternative to ex situ
treatment. We have identified a bacterium that chemically reduces hexavalent
chromium to trivalent chromium under anaerobic conditions. The organism, a
sulfate-reducing Desulfotomaculatum species, produces hydrogen sulfide
which chemically reduces hexavalent chromium. This activity was confirmed by
XANES analysis of untreated and microbially-treated soil containing 6,400 ppm
total chromium as determined by IPS. The organism is tolerant of chromium
concentrations of at least 6,400 ppm, and the XANES analysis clearly
demonstrated the disappearance of any detectable hexavalent chromium from the
soil matrix in less than 120 days.

Key words: biological reduction, chromium(VI), XANES.

Oral presentation in analytical methods session.

97 • USE OF TRACERS FOR THE CHARACTERIZATION OF
SCALE-DEPENDENT SUBSURFACE PROPERTIES: INITIAL EVALUATION

G.R. Barth, T.H. Illangasekare, and H. Rajaram, Department of Civil,
Environmental, and Architectural Engineering, University of Colorado at Boulder,
Boulder, CO, 80309-0428

A great deal of the work done towards the development of effective parameters
has focused on analysis techniques for adapting parameters determined from a
small-scale to a field-scale system. These techniques suffer from the inherent
limitations of developing conclusions about regional or grid-scale flow based on
a limited number of smaller-scale, isolated measurements. A conservative tracer
injected into heterogeneous media will, however, be affected by all the
heterogeneities encountered in the existing flow-fields between the site of
injection and extraction. Instead of attempting to develop a stochastic method
of applying small-scale results, a tracer test provides a direct measurement of
the heterogeneous system. Tracers have potential as a method of evaluating
aquifer characteristics on the same scale at which modeling parameters are
required. A series of tracer tests were performed to assess the ability of
tracers to function as a tool for determining effective field scale parameters.
The main objective for this initial stage was the development of quantitative
methods to interpret breakthrough curves. For the first step, repeatability and
sensitivity to modifications in the flow-field were evaluated. The tests were
performed in a large, two-dimensional tank with a heterogeneous packing. The
flow-field was modified by macroscale entrapment of an LNAPL. Additional tests
were performed in the large tank with a variety of heterogeneous packing before
and after entrapment of contaminants. At the same time a number of small scale
tests were performed to obtain a direct comparison between the results of the
tracer test and other methods of determining effective parameters.

Key words: effective parameters, tracers, scaling.

Oral presentation in analytical methods session.

Program Four Wednesday, May 22, 1996 Bioremediation · Santa Fe Room

98 • FACTORS INFLUENCING THE MICROBIAL METABOLISM OF PAH IN
SOILS

L.M. Carmichael1 and F.K. Pfaender2,
1Ciba-Geigy Corporation, 410 Swing Road, P.O. Box 18300, Greensboro,
NC, 27419-8300, and 2The University of North Carolina at Chapel Hill,
CB#7400, Chapel Hill, NC, 27599-7400

Bioremediation is a feasible technology for removing polycyclic aromatic
hydrocarbons (PAH) from soils, but the low water solubilities of PAH and their
tendency to associate with organic matter may limit their metabolism by
microorganisms. This project investigated the microbial metabolism of several
[14C]-PAH (phenanthrene, pyrene, benz(a)anthracene, chrysene, and
benzo(a)pyrene) in five soils with differing physical characteristics and
differing previous exposure histories to PAH. The primary biotic fate of
[14C]-PAH was mineralization; production of non-mineral metabolites
and incorporation of [14C]-PAH into cellular biomass were minimal
(together accounting for 7 to 10% of the added [14C]-PAH). All
[14C]-PAH, with the exception of [14C]-benzo(a)pyrene,
were readily mineralized in the contaminated soils (9 to 60% of the added
[14C]-PAH). The remaining [14C]-PAH was associated with
the soils, most of which was ethyl acetate-extractable. The fraction of
[14C]-PAH that was mineralized, ethyl acetate-extractable from the
soil or remaining in the soil after extraction, was usually not related to most
characteristics of PAH (solubility and octanol water partition coefficient)
soils (fraction of organic carbon and the extent of native PAH contamination) or
estimates of microbial biomass (general heterotrophic microorganisms and
PAH-degrading microorganisms). The fate of [14C]-PAH was, however,
consistently related to the fraction of silt and clay in the soils. Soils with
larger fractions of silt and clay tended to have lower extents of
mineralization, lower overall recovery efficiencies, a smaller fraction of
[14C]-PAH that was ethyl acetate-extractable from the soil, and a
larger fraction of [14C]-PAH remaining in the soil after extraction
than those soils with a smaller fraction of silt and clay. This suggests that
interaction of PAH with small soil particles may limit their metabolism by
microorganisms.

Key words: polycyclic aromatic hydrocarbons, bioremediation, bioavailability.

Oral presentation in bioremediation session.

99 • AQUEOUS SYSTEM REMEDIATION OF ORGANOHALIDE POLLUTANTS BY
THE UTILIZATION OF AQUATIC ORGANISMS

V.P. Hershberger, Groundwater Technology, Inc., 2501 Yale Boulevard, S.E.,
Suite #204, Albuquerque, NM, 87106

Wildlife toxicological research substantially documents the bioaccumulation
of organohalide pollutants in aquatic organism tissues. Bioaccumulation levels
of organohalide pollutants such as PCBs and DDTr in fish tissues, for example,
may range from thousands to millions of times greater than those levels which
exist in the ambient aquatic environment. Given this pollutant-concentrating
phenomenon, the author proposes the use of fish and other aquatic organisms to
filter, concentrate, and remove bioaccumulable contaminants from polluted
aqueous systems. Harnessing bioaccumulation for the removal of bioaccumulable
contaminants involves the harvesting and subsequent restocking of hardy
macroscopic aquatic organisms which bioaccumulate high contaminant levels in
relatively short periods of time. Studies document that contaminant-resistant
fish adapted to organohalide polluted environments can function in more highly
polluted environments and also bioaccumulate higher contaminant concentrations
in tissues than identical unadapted species.

Recent environmental microbiological literature documents successes in the
microbial mediated destruction of the otherwise recalcitrant organohalide
pollutants such as PCBs and DDTr. Given these research breakthroughs, the author
is proposing and testing the hypothesis that the biodegradation of recalcitrant
organohalide contaminants could be further facilitated if concentrated in fish
or other aquatic organism tissues. Nitrogen, phosphorous, potassium, amino
acids, lipids, and other microbial growth factors occur in abundance in fish
tissues, thus enhancing the bioavailability of the pollutants to the degrading
microbes. Therefore, the bioaccumulator organisms used to remove organohalide
contaminants from a polluted aqueous system could then be composted with
specialized microbes to destroy those normally recalcitrant contaminants.

This research develops possible low-energy applications, including primary or
secondary treatment of extracted ground water, wastewater treatment
augmentation, supplemental wetlands treatment, and natural aquatic environments
restoration.

Key words: ecological engineering, bioremediation, aquaculture,
bioaccumulation.

Oral presentation in bioremediation session.

100 • BIOREMEDIATION ENHANCEMENT BY PHYSICOCHEMICAL
PRETREATMENT

M. Moo-Young, W.A. Anderson, J.M. Scharer, I. van Kamenade, and M. Mehrvar,
Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario,
Canada N2L3G1

Substantial reduction in overall processing time can be realized by
integrated physicochemical pretreatment of xenobiotic contaminants with
subsequent biological mineralization of the resulting intermediates. In case
studies, it is found that chemical preoxidation of phenanthrene with
peroxymonosulfate (Oxone), and photocatalytic preoxidation of tetrahydrofuran,
dioxane, chlorobenzoic acid, and phenol, may significantly overcome the
technoeconomic limitations of stand-alone bioremediation strategies.

Key words: bioremediation, xenobiotics, pre-oxidation.

Oral presentation in bioremediation session.

101 • EVALUATION OF SULFUR-BASED AUTOTROPHIC DENITRIFICATION

D.G. Lampe and T.C. Zhang, Department of Civil Engineering, University of
Nebraska-Lincoln at Omaha Campus, Omaha, NE, 68182-0178

Nitrate contamination of ground and surface waters has become an increasingly
serious problem in the U.S. This research project is mainly concerned with
evaluation of sulfur-based autotrophic denitrification processes (SBADP), which
employ Thiobacillus denitrificans to reduce nitrate to nitrogen gas using
elemental sulfur as the electron donor, carbon dioxide as carbon source for
growth, and nitrate as the electron acceptor.

The objectives of this study are: (1) to test and evaluate the SBADP for
above-ground treatment of nitrate-contaminated water using lab-scale upflow
anaerobic fixed-bed reactors; and (2) to conduct kinetic studies on in
situ remediation of nitrate-contaminated ground water with the SBADP using
anaerobic batch reactors.

A 3.4 liter continuously-stirred tank reactor (CSTR) with gas collection
utilizes thiosulfate as the electron donor and has served as a seed source for
the batch reactors and fixed-bed reactors. Four upflow anaerobic fixed-bed
reactors are constructed from 2.5 in. I. D. acrylic column. The empty bed
reactor volume is 1.53 liters and the granular sulfur and limestone media
working volume is 1.11 liters.

Start-up of the column reactors began with a series of inoculations from the
CSTR mixed liquor; quasi-steady-state conditions were achieved after four weeks.
Under quasi-steady-state conditions, the influent concentrations were 33 mg
NO3--N/1, the loading rate was 75 mg
NO3--N/1/d, and the average HRT was 16.75 hours. Four
columns with sulfur:limestone ratios of 1:3, 1:1, 3:1, and sulfur only, revealed
nitrate reductions of 76%, 97%, 99%, and 52%, respectively. The HRT of column
reactors will be shortened to be 8, 2, and 0.5 hrs., and the performance will be
further evaluated.

Soil-elemental sulfur anaerobic batch tests are designed to generate
information on kinetics of in situ remediation of nitrate-contaminated ground
water using the SBADP. The experimental results obtained from the CSTR and batch
reactors demonstrated that sulfate concentration, nitrite, pH, and DO
concentrations in the reactors are key parameters affecting the performance of
the CSTR or batch reactors. SO42- is produced and pH
decreases during the denitrification process. The denitrification will be
seriously inhibited at high concentration of sulfate (> 5,000 mg/l) and low
pH (about 5.6 to 6.0).

Preliminary results for sulfur-based autotrophic denitrification have been
promising. Further research will provide a clearer picture of performance in the
existing bench-scale systems. Long term goals include application of this
technology to pilot-scale systems in the quest for feasible denitrification
alternatives.

Key words: nitrate, autotrophic denitrification, ground water,
bioremediation, sulfur.

Oral presentation in bioremediation session.

102 • TREATMENT OF TRICHLOROETHENE (TCE) WITH A
FLUIDIZED-BED BIOREACTOR

R.L . Segar, Jr., and S.A. Vivek, Department of Civil Engineering. University
of Missouri-Columbia, Columbia, MO, 65211

Many types of bench-scale bioreactors have met limited success with the
treatment of trichloroethene (TCE) contaminated water. This research project
used a fluidized-bed biofilm reactor (FBBR) to obtain cometabolism of TCE by
microorganisms grown on phenol. The intended application of the reactor is
primarily for treatment of ground water extracted during aquifer remediation.

The FBBR provided a high level of microbial activity and avoided the plugging
problems associated with packed-bed reactors. Experiments were conducted to
determine the removal of TCE for various phenol loading rates and pulsed-feeding
techniques. High levels of phenol feeding inhibited TCE degradation, and phenol
was not completely removed. Low levels of phenol feeding did not sustain TCE
removal over time. A phenol to TCE mass ratio of 50:1 provided 70-80% removal of
0.1 mg/l TCE at an EBCT of 3 minutes. Phenol was not detected in the reactor
effluent at those conditions. The kinetic performance was extraordinary compared
to earlier bioreactor studies and the process holds promise as an alternative to
air-stripping and granular activated carbon. Higher removals of TCE could be
obtained with the FBBR in field conditions where the reactor height may be
extended.

Key words: biofilm, fluidized-bed, trichloroethene, phenol, ground water
remediation.

Oral presentation in bioremediation session.

103 • ANAEROBIC BIODEGRADATION OF TOLUENE IN A PLUG-FLOW
DIGESTER

T. Liu, K. Fukushi, and S. Ghosh, Department of Civil and Environmental
Engineering, The University of Utah, Salt Lake City, UT, 84112

Toluene is an important organic constituent of gasoline; it is widely used
for the synthesis of industrial chemicals and pesticides. However, toluene and
its oxidation products are carcinogenic and neurotoxic; it is also classified as
a priority pollutant by the United States Environmental Protection Agency. Due
to inadequate treatment techniques and/or indiscriminate disposal on the land,
and surface and ground waters, toluene is causing serious pollution problems in
many places, including the U.S.-Mexican border area. Leakage from underground
storage tanks and pipelines, accidental spills, and leaching landfills are the
major resources of toluene entering streams, soil, sediments, and ground water.

This paper presents the application of a continuous-flow, mesophilic 35ºC
anaerobic plugflow digester for cometabolic degradation of toluene by an
anaerobic microbial consortium with conventional liquid and solid pollutants
serving as the major carbon sources. The results of this research showed that
sequential acidogenic and methanogenic fermentation occurring in the plugflow
reactor can stabilize and detoxify mixed conventional and hazardous, liquid and
solid wastes with simultaneous production of a methane-rich (79%) fuel gas. The
plug-flow digester removed 95% of the toluene in the liquid phase with a
simultaneous total COD reduction of 96% at an hydraulic retention time (HRT) of
approximately 13 days and an organic loading rate of 0.81 kg
COD/m3-day. The concentration of toluene in the effluent was 2 mg/l
compared with an influent concentration of 50 mg/l. The amount of toluene
released to the confined gas phase was about 2.6% of the toluene loading to the
digester. The gas phase toluene is readily oxidized to CO2 and water
during combustion of this fuel gas. The plug-flow digester showed good
performance in terms of removal efficiency and degradation rate of toluene and
conventional organic substrates.

A kinetic model derived from the Monod equation was utilized to describe
cometabolic toluene degradation. A model applicable to intermediate
concentrations of toluene was used to fit toluene degradation profiles in the
plug-flow digester. It was assumed that cometabolism of toluene did not support
cell growth. The kinetic parameters of half-velocity constant (Ks)
and the maximum rate of toluene utilization (C) were estimated by applying a
nonlinear regression to steady-state toluene concentration profiles. Values of
Ks and C were 12.2 mg/l and 6.2 mg/l-day, respectively. This model
enabled quantitative prediction of toluene degradation in an anaerobic plug-flow
reactor. The plug-flow digester continuously charged with cometabolic substrates
with a COD of 11,000 mg/l exhibited better performance than that of other
systems.

Key words: biodegradation, cometabolism, toluene, plug-flow.

Oral presentation in bioremediation session.

104 • RELATIONSHIP BETWEEN AEROBIC BIODEGRADATION RATES,
CHEMICAL STRUCTURE, AND SOIL TYPE FOR SELECTED PETROLEUM HYDROCARBONS

W.J. Doucette1, J. Yuan1, B. Bugbee2, A.
Ravipaty1, and R.R. Dupont1, 1Utah Water
Research Laboratory and 2Crop Physiology Laboratory, Utah State
University, Logan, UT, 84322

Despite its importance in environmental fate assessments, quantitative
information describing the biodegradation of individual petroleum hydrocarbons
in soils is often lacking. In addition, biodegradation rates reported for
specific chemicals often vary dramatically from one study to another. In many
cases it's difficult to determine if the differences are due to variables
associated with soil type, such as moisture, nutrients, and oxygen level, or to
differences in the technique used to measure biodegradation. Biodegradation
rates are typically determined by directly measuring the disappearance of the
chemical of interest over time or indirectly by measuring evolved CO2
or O2 consumption. Indirect respirometric methods are generally
simpler, quicker, and cheaper than direct methods and are often used to quantify
biodegradation at field sites. We measured aerobic biodegradation rates for 16
individual aliphatic and aromatic petroleum hydrocarbons in four soils using
respirometry. The biodegradation of petroleum fuel mixtures was also examined
using the same technique. The relationships between biodegradation rates,
chemical structure, and soil type will be described.

Key words: alkanes, aromatics, microcosm, respirometry.

Oral presentation in bioremediation session.

105 • INFLUENCE OF MOISTURE CONTENT ON BIOREMEDIATION OF
ORGANIC CONTAMINANTS IN THE SUBSOIL

B. Liu1, M.K. Banks1, A.P. Schwab2, and L.
Schuckman1, 1Department of Civil Engineering and
2Department of Agronomy, Kansas State University, Manhattan, KS,
66506

Hazardous organic chemicals, especially petroleum hydrocarbons, are major
contaminants of soil and ground water. Bioremediation of organic contaminants
has been studied with great interest recently by environmental scientists.
However, uncertainties remain concerning its effectiveness for certain
compounds, including petroleum hydrocarbons, and factors influencing the rate
and extent of degradation in certain environments. One of the most important
factors affecting bioremediation is moisture content. Optimal moisture content
for microorganisms in the soil may accelerate degradation significantly. In this
research, jet fuel was used as the contaminant. Clay soil was collected at 1
meter depth from the North Agronomy Farm, Manhattan, KS. Biodegradation of jet
fuel in the clay soil with five different moisture contents was investigated at
25°C and 4ºC. Microorganisms in the contaminated soil were counted using plate
counts. The range of optimal moisture contents was estimated based on literature
values. Moisture contents from 18% (g water/g wet soil) to 25% (g water/g wet
soil) showed relatively high degradation rates. Degradation rates at room
temperature and 4°C were compared. The five chemicals in the mixture were also
identified, and p-xylene and decane were degraded most readily.

Key words: bioremediation, petroleum hydrocarbons, microorganisms, subsoil,
degradation.

Oral presentation in bioremediation session.

106 • BIOREMEDIATION BACTERIA TO PROTECT PLANTS FROM
PENTACHLOROPHENOL TOXICITY IN SOIL

W.F. Pfender, Plant Pathology Department, Kansas State University, Manhattan,
KS, 66506-5502

Growth of plants in contaminated surface soils can be beneficial in
remediating polluted sites, by plant and/or associated microbial metabolism of
pollutants, and by stabilization of polluted soil against erosion. However,
phytotoxicity and plant bioconcentration of some pollutants can interfere with
successful vegetative site restoration. We found that Pseudomonas strain
SR3, when applied to seeds of proso millet (Panicum miliaceum L.),
protected the growing plants from phytotoxicity of pentachlorophenol (PCP) in
the soil during a 4-week growth-chamber study. Untreated plants in the
contaminated soil grew very poorly, whereas in soil receiving the
bacteria-treated seed, plants grew well and PCP was reduced from 175 ppm to 3
ppm. When bacteria were mixed thoroughly into the soil at 5 X 106
cfu/g, in the absence of plants, PCP was likewise reduced from 175 to 5 ppm. PCP
in soil with non-inoculated plants remained approximately at the initial level
(165 ppm extractable PCP). Roots without applied bacteria concentrated PCP from
the soil into root tissue to a ratio of 13:1 (final root concentration: initial
soil concentration, both in ppm by weight), whereas the bacteria-treated roots
concentrated PCP at a ratio of 0.09:1.

Key words: pentachlorophenol, vegetative remediation, plants, bioremediation,
soil, bacteria.

Oral presentation in bioremediation session.

Bioremediation and Volatile Compounds · Santa Fe Room

107 • DESIGN OF CLOSED CHAMBERS FOR MEASURING
PHYTOREMEDIATION: OPTIMIZING PLANT GROWTH AND CHEMICAL MASS BALANCE

B. Bugbee1 and W.J. Doucette2, 1Crop
Physiology Laboratory and 2Utah Water Research Laboratory, Utah State
University, Logan, UT, 84322

The potential value of phytoremediation has been demonstrated in both
laboratory and field settings, but rigorously quantifying its effectiveness has
been difficult, especially for volatile organic chemicals. Sealed growth
chambers are necessary to quantitatively determine the fate of volatile organics
in plant/soil systems. However, chamber design is often a compromise between
optimum plant growth and chemical mass balance. Low humidities are necessary to
promote normal transpiration rates in sealed chambers, but procedures for
obtaining low humidity increase the difficulty of recovering volatile organic
compounds. Vigorous plant growth is closely associated with large fluxes of
water vapor in transpiration This water vapor can be condensed and removed from
the chamber, but rapid air flow rates through the chamber are necessary to
prevent the unnatural accumulation of volatile organic compounds in the chamber
air. High flow rates mean that large, efficient traps are necessary to recover
volatiles form the air stream. Large soil containers are also necessary to
simulate the root-zone oxygen and water conditions in the field. Unfortunately,
increased soil volume increases the difficulty in obtaining a good mass balance
in the soil compartment. Cost-effective options for simulating the field
environment, optimizing plant growth. and obtaining mass balance of volatile
organic compounds will be discussed.

Key words: humidity, transpiration rates, volatile organic compounds,
root-zone oxygen.

Oral presentation in bioremediation and volatile compounds session.

108 • EXPERIMENTAL AND MODELING STUDIES OF THE FATE OF
TRICHLOROETHYLENE IN A CHAMBER IN THE PRESENCE OF ALFALFA PLANTS

N. Muralidharan1, N.K. Russell2, L.C.
Davis3, and L.E. Erickson1, Departments of
1Chemical Engineering, 2Chemistry, and
3Biochemistry, Kansas State University, Manhattan, KS, 66506

Experiments were performed in a laboratory chamber to investigate the
influence of alfalfa plants on the fate of trichloroethylene (TCE) which is
being fed at a concentration of 200 ml/l in the entering ground water. The
dimensions of the chamber are 180 cm in axial length, 35 cm in depth, and 10 cm
in width. Concentrations of TCE in the aqueous phase were measured using gas
chromatographic headspace analysis technique. FT-IR instrumentation was employed
to monitor the evapotranspirational fluxes of TCE from the soil to the headspace
of the chamber. Modeling the fate of TCE in this chamber was also attempted
simultaneously. Models assuming non-equilibrium partitioning between gas, water,
and solid phases were compared to equilibrium based models. Non-equilibrium
transport was modeled as a diffusional mass transfer resistance across a film
separating the corresponding phases. The boundary condition at the surface was
modified to account for free gas phase diffusion of the volatile TCE contaminant
to the headspace of the chamber. The simulation results are being compared with
experimental data on the fate of TCE.

Key words: volatile organics, headspace, non-equilibrium phenomenon, mass
transfer.

Oral presentation in bioremediation and volatile compounds session.

109 • THE EFFECT OF SOIL WETTING AND DRYING PROCESSES ON THE
TRANSPORT BEHAVIOR OF VOLATILE ORGANIC COMPOUNDS IN UNSATURATED POROUS MEDIA

I.Y. Padilla, M.H. Conklin, and T.C.-J. Yeh, Department of Hydrology and
Water Resources, University of Arizona, Tucson, AZ, 85721

Many organic contaminants present in subsurface environments are volatile and
slightly soluble in water. Transport of these vapors and solutes through the
vadose zone may result in long-term contamination of ground water resources and
human exposure to these chemicals through contact, inhalation, and/or oral
consumption. The transport behavior of volatile organic compounds (VOCs) in
unsaturated porous media has been investigated at different water contents. More
specifically, this study has identified the effects of wetting and drying
(hysteretic) processes on dispersive and mass transfer transport mechanisms.
Transport experiments were conducted by passing a finite pulse of non-reactive
chemicals and trichloroethylene (TCE) through a column packed with silica sand
under different water contents and wetting and drying conditions. Chemical
concentrations at the outlet of the column were monitored and the breakthrough
data was simulated using a numerical transport model. Mass transfer coefficients
for TCE and dispersivity values for a silica sand have been determined for each
of the experimental conditions imposed.

This work enhances our understanding of VOCs transport in subsurface
environments and improves our ability to predict the fate and transport of
organic contaminants under variable water-saturated conditions. Ultimately, this
research will improve our ability to assess and select effective clean-up
strategies for many hazardous waste sites and minimize exposure of these
pollutant to humans and ecosystems.

Key words: transport, unsaturated, volatile organic compounds, hysteresis,
vadose.

Oral presentation in bioremediation and volatile compounds session.

110 • COMPARISON OF FIELD AND LABORATORY METHODS FOR VOCS
AND MAJOR GASES IN SOIL VAPOR

J.R. Forbes, R. Schmidt-Petersen, B. Casadevall, and D. Reaber, Daniel B.
Stephens & Associates, Inc., 6020 Academy N.E., Albuquerque, NM, 87109,
e-mail: [email-masked]

Soil gas sampling and analysis have become increasingly important during
environmental site investigations. In addition to the well-known use of shallow
soil vapor surveys to locate potential contaminant source areas, variations in
the composition of soil gas samples collected from deeper depths can often
provide important clues regarding the nature and extent of volatile subsurface
contaminants. Deep soil gas data are particularly helpful in understanding the
vadose zone hydrologic process underlying sites where organic compounds have
been released or buried, such as liquid hydrocarbon spill sites and landfills.
We have installed several dozen permanent multi-port soil gas (MPSG) monitor
wells of unique design at sites in Arizona and New Mexico to characterize the
distribution of volatile organic compounds (VOCs) and major gases in soil vapor
with depth. Each MPSG well is installed within a single borehole and allows soil
gas samples to be drawn from multiple discrete depth intervals in the vadose
zone. If desired, the MPSG well can be coupled with a standard ground water
monitor well to permit sampling of the underlying ground water. This allows for
direct comparison of ground-water quality with that of the overlying soil vapor.

Soil gas samples collected in evacuated stainless-steel SUMMAR
canisters were submitted to the laboratory for VOC analysis by GC/MS using EPA
Method TO-14. In addition, the concentrations of major gases (carbon dioxide,
oxygen, methane, nitrogen, and hydrogen) were determined in the laboratory by
gas chromatography/thermal conductivity detection (GC/TCD). The difficulty and
expense of obtaining reliable laboratory data for soil gas samples led us to
explore the possibility of determining soil gas concentrations in the field
using portable instruments. A Landtec GA-90 multi-gas monitor was used to
determine the concentrations of CO2, CH4, and
O2. In general, the field and laboratory results compared very well
when the GA-90 instrument was calibrated frequently using calibration gases that
span the concentration range of interest. The presence of high concentrations
(>100 ppmv) of fuel hydrocarbons in some soil vapor samples was found to
interfere with the methane detector, however, causing erroneously high methane
readings.

A Brùel & Kjær Model 1302 photo-acoustic multi-gas monitor was used to
determine the soil gas concentrations of trichloroethene (TCE) and
tetrachloroethene (PCE) in the field. These results were compared with VOC
concentrations determined in the laboratory using Method TO-14. TCE
concentrations in soil gas ranged from the sub-ppm level to the volume percent
level, a range of over 5 orders of magnitude. For TCE at concentrations above
about 1 ppmv, the two data sets compared remarkably well, with an R2
value of about 0.9. The correlation for PCE was not as good. The results of this
study indicate that high quality soil gas data can be obtained using existing
field instruments in less time and at far lower cost than the equivalent
laboratory analyses, provided that the primary VOCs in the soil vapor are known
from previous analyses.

Key words: soil gas, trichloroethene, landfill, vadose.

Oral presentation in bioremediation and volatile compounds session.

Program Four Thursday, May 23, 1996 Phytoremediation · Santa Fe Room

111 • PHYTOREMEDIATION AT HAZARDOUS WASTE SITES

J. Burken, A. Dietz, J. Jordahl, W. Schnabel, P. Thompson, L.A. Licht, P.J.J.
Alvarez, and J.L. Schnoor1, Department of Civil and Environmental
Research, 116 Engineering Research Facility, The University of Iowa. Iowa City,
IA, 52242, 1e-mail: [email-masked]

Phytoremediation is the use of vegetation for in situ treatment of
hazardous wastes. It is a form of ecological engineering that has proven
effective and relatively inexpensive at several pilot- and full-scale sites.
Plants have shown the ability to withstand greater concentrations of organic
pollutants than most microorganisms, and they can take up chemicals quickly and
convert them to less toxic metabolites. In addition, they stimulate the
degradation of organic chemicals in the rhizosphere by the release of root
exudates, enzymes, and the build-up of organic carbon in the soil. In this
summary paper, recent research results will be presented on pilot- and
full-scale applications using hybrid poplar trees at hazardous waste sites for
atrazine, 2,4,6-trinitrotoluene (TNT), trichloroethylene (TCE), and BTEX
compounds (benzene, toluene, ethylbenzene, and xylenes). Key findings include
the importance of direct plant uptake for organics with intermediate
octanol-water partition coefficients (log Kow = 1.0-3.5), the
metabolism of some organics in leaf and stem tissue, the release of VOCs through
leaf tissue to the atmosphere, and the creation of "bound-residue" in the plant
based on 14C-label studies.

Key words: phytoremediation, hazardous waste, bioremediation, contaminated
soil, ground water.

Oral presentation in phytoremediation session.

112 • REMEDIATION OF PESTICIDE WASTES USING RHIZOSPHERE
MICROORGANISMS

T.A. Anderson, E.L. Kruger, and J.R. Coats, Pesticide Toxicology Laboratory,
Iowa State University, Ames, IA, 50011-3140

Many agrochemical dealerships have experienced soil and water contamination
problems from normal operating procedures and accidents during the last 40
years. In most instances, the costs associated with current cleanup technologies
preclude their use at these facilities. However, phytoremediation may provide a
more economical approach if vegetation can survive on these sites and encourage
microbial proliferation and degradation.

We have demonstrated that the degradation of atrazine, metolachlor, and
trifluralin was significantly greater in rhizosphere soils from Kochia
scoparia than in nonvegetated soils. In addition, mineralization of
14C-atrazine in a mixture of atrazine and metolachlor (50 µg/g each)
was significantly greater in Kochia scoparia rhizosphere soils than
nonvegetated soils. In both studies, soils were collected from retail
agrochemical dealer sites.

We have also screened rhizosphere soils from several other plant species for
their ability to mineralize atrazine or metolachlor at concentrations typical of
point-source contamination (50 mg/g). In addition, we have tested the
germination and survivability of various plants in contaminated soil. Both of
these tests are attempts to find plants more amenable for use in
phytoremediation.

Key words: rhizosphere, phytoremediation, atrazine, vegetation, degradation.

Oral presentation in phytoremediation session.

113 • VARIATION IN ROOT GROWTH AMONG FOUR SORGHUM VARIETIES
GROWN IN SOIL CONTAMINATED WITH PETROLEUM HYDROCARBONS

P.A. Kulakow1, Z. Chen2, K. Rathbone1, A.P.
Schwab1, M.K. Banks2, and P.J. Bramel-Cox1,
Departments of 1Agronomy and 2Civil Engineering, Kansas
State University, Manhattan, KS, 66506-5501

Variation among genotypes in root growth may contribute to variation in the
ability of plants to enhance degradation of petroleum hydrocarbons, a process
called phytoremediation. Four varieties of grain sorghum, Sorghum bicolor
(L.) Moench, were compared in a greenhouse experiment using three soils:
uncontaminated soil, soil contaminated with 0.25% crude oil, and soil
contaminated with 0.25% synthetic diesel. Root length density and root surface
area were estimated at the fifth leaf and boot growth stages. Variation in root
parameters among the varieties was determined for each soil type and compared
with the degradation of soil contaminants. Understanding of the role of root
growth in enhancing the degradation of petroleum hydrocarbons will aid in
selection of species and varieties for use in phytoremediation.

Key words: phytoremediation, root growth, petroleum hydrocarbons, sorghum,
genetic variation.

Oral presentation in phytoremediation session.

114 • DETECTION OF AGRONOMIC AND BIOREMEDIATION
VARIABILITIES BETWEEN ALFALFA CLONES GROWN IN CRUDE-OIL CONTAMINATED SOILS

Z. Chen1, A.P. Schwab2, M.K. Banks1, C.C.
Wiltse3, and W.L. Rooney3, Departments of
1Civil Engineering and 2Agronomy, Kansas State University,
Manhattan, KS, 66506, and 3Department of Soil and Crop Science Texas
A&M University, College Station, TX, 77843

Phytoremediation may be an economical way to remediate crude-oil contaminated
soils. Studies indicate that alfalfa (Medicago sativa, L.) is effective
at enhancing degradation of organic chemicals in soils (Schwab and Banks, 1994).
Due to the highly heterozygous nature of alfalfa, it is likely that variability
exists between cultivars, or plants within a cultivar, for agronomic performance
in contaminated soil. If variability does exist, it should be possible to
improve plant performance for agronomic and phytoremediation characteristics.
The objectives of the study were: (1) to determine if variability exists between
alfalfa genotypes for agronomic performance in crude-oil contaminated soil, (2)
to compare the performance of clonally-replicated genotypes in uncontaminated
versus crude-oil contaminated soil, and (3) to assess the bioremediation
potential of alfalfa genotypes. Twenty cloned genotypes from the alfalfa
cultivar 'Riley' were transplanted into 2% (w/w) crude-oil contaminated soil. A
number of agronomic parameters were measured throughout the experiment,
including forage yield, plant height, and maturity. After one year, differences
existed between genotypes for total forage yield (P<0.05), maturity at
harvest (P<0.001), and plant height (P<0.01). Eight of the 20 genotypes
were also grown in uncontaminated soil. After one year, the forage yield in
contaminated soil was 32% of the same clones grown in uncontaminated soil.
Clones grown in contaminated soil were less mature and shorter than when they
were grown in uncontaminated soil. While overall agronomic performance is
reduced in contaminated soil, enough variability exists between genotypes to
develop alfalfa populations adapted for growth in contaminated soil. In
addition, differences in bioremediation efficiency of these cloned genotypes may
exist and may be enhanced after a period of time.

Key words: phytoremediation, alfalfa genotype, agronomic performance.

Oral presentation in phytoremediation session.

115 • USE OF BIOMARKERS TO ASSESS PHYTOREMEDIATION OF
PETROLEUM-CONTAMINATED SOILS

E.X. Wang, M.K. Banks, and A.P. Schwab, Departments of Agronomy and Civil
Engineering, Kansas State University, Manhattan, KS, 66506-5501

Accurately quantifying biodegradation losses in the field are often
complicated by spatial variability, dilution, leaching, and volatilization. To
better evaluate biodegradation rates, compositional changes of hydrocarbons are
monitored through column chromatography to determine class distributions. The
relative distribution of saturates, aromatics, and polar compounds change as
biodegradation progresses. Target compounds (e.g., hopane,
methyldibenzothiophenes, and methylchrysenes) in saturate and aromatic fractions
are determined by GC/FID and GC/MS. As biomarkers or "fingerprints," these
compounds are present in contaminated soils at relatively high concentrations
and are subject to little interference from evaporative weathering. Therefore,
they are distinctively used to indicate the occurrence of microbial degradation
of oils. Contaminated soil samples from different soil types, plant treatments,
and biodegradation stages are measured over periods of phytoremediation.

Key words: class distribution, dibenzothiophenes, chrysenes, hopane,
biodegradation, GC/MS.

Oral presentation in phytoremediation session.

116 • PHYTOREMEDIATION OF PETROLEUM CONTAMINATED SOIL-A
FIELD ASSESSMENT

M.K. Banks1, A.P. Schwab2, and R.S.
Govindaraju1, 1Department of Civil Engineering and
2Department of Agronomy, Kansas State University, Manhattan, KS,
66506

Greenhouse studies have indicated that vegetative remediation is a feasible
method for clean-up of surface soil contaminated with petroleum products.
However, field demonstrations are important to exhibit this new technology to
the industrial community. In this project, several petroleum-contaminated field
sites have been chosen in collaboration with three industrial partners. These
sites have been thoroughly characterized for chemical properties, physical
properties, and initial contaminant concentrations. A variety of plant species
have been established on the sites, including warm and cool season grasses and
legumes. Soil analyses for the target compounds over time indicate that the
interaction between plants and rhizosphere microflora significantly enhances
remediation of the contaminated soils. Continued monitoring will allow us to
assess the efficiency and applicability of this remediation approach.

Key words: bioremediation, phytoremediation, plants, contaminant, soil,
ground water.

Oral presentation in phytoremediation session.

Posters · Taos, Las Cruces, and Yucatan Rooms and Pre-Convention Area

1 • INNOVATIVE TECHNOLOGIES FOR THE REMEDIATION OF SOIL AND
GROUND WATER FROM THE DEPARTMENT OF ENERGY, OFFICE OF TECHNOLOGY SYSTEMS

V.M. Ceci1 and S.P. Mathur2, 1BDM Federal,
Suite 400, 555 Quince Orchard Road, Gaithersburg, MD, 20878, and
2U.S. Department of Energy, Office of Technology Systems, Cloverleaf
Building, 19901 Germantown Road, Germantown, MD, 20874

For over fifty years, the Department of Energy (DOE) or its predecessor
agencies have designed, manufactured, and tested nuclear weapons for national
defense. Production, testing, and decommissioning of these weapons has resulted
in the contamination of vast tracts of property. Today, DOE is responsible for
waste management and remediation of more than 100 contaminated installations in
36 states and territories. This includes 3,700 sites occupying 26,000 acres,
with hazardous- or radioactive-contaminated surface and ground water, soil, or
structures requiring remediation. This number continues to grow as new sites are
defined. There are approximately 500 surplus facilities awaiting decontamination
and decommissioning and approximately 5,000 peripheral properties (business and
residences) that have soil contaminated with uranium tailings.

As a result of past disposal practices, numerous DOE facilities exhibit
contaminant plumes emanating from waste disposal areas. It is currently
estimated that over 600 billion gallons of ground water contaminated with
radioactive and/or hazardous wastes exist within the DOE complex. Heavy metals,
radionuclides, volatile organic compounds (VOCs), and DNAPLs (dense nonaqueous
phase liquids) are estimated to contaminate over 200 million cubic yards of
soil. In addition, over 25 contaminant plumes extend off DOE sites, and two
major drinking water aquifers are threatened (Ogallala with volatile organic
compounds, and Miami Aquifer with uranium). Current technologies are costly and
often ineffective for the characterization (especially for DNAPLs) and cleanup
of soils and ground water, or to prevent further migration.

The immediate challenge, therefore, is to develop a cost-effective,
environmentally-sound approach to cleaning up these contaminated soils and
waters. The approach should significantly reduce the volume of contaminated
material that requires special handling, packaging, and costly disposal, or if
possible, remediate the site in situ.

To that end, five major remediation and waste management problem areas within
the DOE complex have been targeted for action on the basis of risk, prevalence,
or need for technology development to meet environmental requirements and
regulations. Termed "Focus Areas," the Office of Environmental Management (EM),
Office of Science and Technology (OST) has initiated the Landfill Stabilization
Focus Area (LSFA) and the Contaminant Plumes Containment and Remediation Focus
Area (PFA) for the development and deployment of safer, more cost-effective and
efficient technologies which satisfy DOE site needs. These focus areas are
structured to meet demands in five technology areas: assessment, treatment,
containment, stabilization, and retrieval.

Remediation technologies under development by DOE include physical, chemical,
and biological treatment, barrier technology, electrokinetics, stream stripping,
and in situ vitrification, among others.

This poster session will outline the research currently underway by
presenting an overview of the site needs, technology development activities,
some of the more mature technologies ready for implementation, and
accomplishments made.

Key words: remediation, innovative, technology, DOE.

Poster presentation.

2 • HEAVY METAL REMOVAL AND RECOVERY BY COMBINED
PHYTOREMEDIATION AND ANAEROBIC FERMENTATION

Z.A. Samani1, K. Fukushi2, and S. Ghosh2,
1Civil Engineering Department, New Mexico State University, Las
Cruces, NM, 88003, and 2Civil & Environmental Engineering
Department, The University of Utah, Salt Lake City, UT, 84112

The release of hazardous heavy metals into soil, surface water, and ground
water is a major concern. Heavy metal contamination is caused by various
industrial activities including the mining, metallurgical, and electroplating
industries. Recent research at the University of Utah has shown that microbial
biopolymers derived from special bacterial cultures can be very effective in
binding heavy metals. These special cultures were developed in the presence of
selected biochemical stimulants. Heavy metal removals up to 130% of the dry cell
weight were obtained with Cd, Cu, Pb, and Ag. The observed biopolymeric binding
capacity is significantly higher than that of activated carbon and other
conventional metal-removing media. It is possible to immobilize these special
bacterial cells and biopolymers on solid substrates. Photosynthetic materials
such as wheat and barley straws were found to remove Pb and Cr up to two percent
of the dry weight of straw.

The objective of the research presented here was to examine the technical
feasibility of removing heavy metals from contaminated waters using a
straw-packed biofilter. Bacterial cells and biopolymers developed in the
presence of the stimulants mentioned above are immobilized on solid particles of
straw packed into the biofilter. These biofilters act as fixed-film sequential
batch reactors (FFSBR) that are used to sequester heavy metals from
metal-containing influents. Metals complexed by the biofilter media are eluted
with organic acid mixtures obtained from a separate acidogenic reactor operated
with fresh or spent straw from the FFSBR. Metals are leached out of the
biofilters and recovered as esters of organic acids. Heavy metals are recovered
from the leachate by chemical precipitation or by methane fermentation of the
organic acid esters with sulfide precipitation.

Key words: heavy metal, phytoremediation, acid fermentation.

Poster presentation.

3 • DNAPL MIGRATION THROUGH A MULTI-AQUIFER AND FRACTURED
AQUITARD SYSTEM

D.B. Stephens, M.A. Prieksat, J.A. Kelsey, and M.D. Ankeny, Daniel B.
Stephens and Associates, 6020 Academy Road, N.E., Suite 100, Albuquerque, NM,
87109

DNAPL can quickly travel through fractured aquitards when hydrodynamic
conditions exist. The flow of DNAPL through the fracture is often driven
primarily by hydraulic head with density differences being a secondary
component. Laboratory experiments demonstrated the flow of trichloroethane (TCA)
through a system consisting of an upper unconfined aquifer and a lower
partially-saturated aquifer. These aquifers were separated by a fractured
aquitard, across which ground water flow was downward. This process is presented
through a series of still photos and a video. The visual results show rapid
transport of TCA through the fracture, and the observations were predicted
rather well with a multiphase computer code.

Key words: dense nonaqueous phase liquids, fracture, aquitard.

Poster presentation.

4 • ELECTROKINETIC REMEDIATION OF SOIL CONTAMINATED WITH
OILFIELD BRINE

C.E. Davis and T.M. Harris, Departments of Chemical Engineering and
Chemistry, University of Tulsa, 600 S. College Avenue, Tulsa, OK, 74104

The contamination of soil with brine (salt water) is a common environmental
problem associated with the onshore production of oil. The use of electrokinetic
remediation to remove sodium chloride from soil was investigated. Experiments
were conducted in a test cell that features a "well" containing a stainless
steel wire mesh electrode at either end. Experiments involved both real
contaminated soil samples and synthetic samples prepared from sand and bentonite
and saturated with sodium chloride. During an experiment, distilled water was
added incrementally to the cell, and that which accumulated in each well was
removed and analyzed. The removal of both chloride ion and sodium ion from the
soil was enhanced at the anode well by the application of an applied potential.
The addition of calcium sulfate to the soil eliminated the plugging off of soil
porosity resulting from pH changes that occurred in the vicinity of both
electrodes.

Key words: soil, brine contamination, petroleum, production, electrokinetic
remediation.

Poster presentation.

5 • WASTE WATER TREATMENT USING FERRATE TO REMEDIATE AQUEOUS
AZODYES

M.D. Johnson, B. Hornstein, and R. Wingo, Department of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, NM, 88003

Ferrate represents a new alternative treatment procedure for the rapid
chemical oxidation of organic wastes which is safer than ozone or chlorine and
has no undesirable side products, such as with permanganate. The aerobic ferrate
oxidation of organic compounds produces ferric hydroxide as the sole reduction
product.

[FeO4]2- --> Fe(OH)3 (s)

This reaction with a variety of organic dyes has been studied in detail and
the results will be reported.

Key words: remediation, wastewater, ground water.

Poster presentation.

6 • CONTAMINANT MONITORING OF RODENTS AT A RADIOACTIVE WASTE
BURIAL SITE, LOS ALAMOS NATIONAL LABORATORY

J. Biggs, K. Bennett, and P.R. Fresquez, Los Alamos National Laboratory, Mail
Stop M887, Los Alamos, NM, 87545

Small mammals were sampled at two waste burial sites (1 and 2) at Los Alamos
National Laboratory and a control site (Site 3) to identify radionuclides that
are present within surface and subsurface soils at waste burial sites, to
compare the amount of radionuclide uptake by small mammals at waste burial sites
to a control site, and to identify the primary mode of contamination to small
mammals, either through surface contact or ingestion/inhalation. Three composite
samples of at least five animals per sample were collected at each site. Pelts
and carcasses of each animal were separated and analyzed independently. Samples
were analyzed for 241Am, 90Sr, 238Pu,
239Pu, total U, and gamma spectroscopy (including 137Cs).
Significantly higher (parametric t-test at p=0.05) levels of total U,
241Am, 238Pu, 239Pu, and 40K were
detected in pelts as compared to the carcasses of small mammals at TA-54.
Concentrations of other measured radionuclides in carcasses were nearly equal to
or exceeded the mean concentrations in the pelts. Our results show higher
concentrations in pelts compared to carcasses, which is similar to what has been
found at waste burial/contaminated sites outside of Los Alamos National
Laboratory. Site 1 had significantly higher (alpha=0.05, P=0.0095) total U
concentrations in carcasses than Sites 2 and 3. Site 2 had significantly higher
(alpha=0.05, P=0.0195) 239Pu concentrations in carcasses than either
Site 1 or Site 3. A significant difference in 90Sr concentration
existed between Sites 1 and 2 (alpha=0.05, P=0.0681) and concentrations of 40K
at Site 1 were significantly different from Site 3.

Key words: small mammals, radionuclides, contaminant, carcasses.

Poster presentation.

7 • CONTAMINANT MONITORING OF BIOTA DOWNSTREAM OF A
RADIOACTIVE LIQUID WASTE TREATMENT FACILITY, LOS ALAMOS NATIONAL LABORATORY

K. Bennett, J. Biggs, and P.R. Fresquez, Los Alamos National Laboratory, Mail
Stop M887, Los Alamos, NM, 87545

Small mammals, plants, and sediments were sampled at one upstream location
(Site 1) and two downstream locations (Site 2 and Site 3) from a radioactive
liquid waste treatment facility at Los Alamos National Laboratory, Los Alamos
County, New Mexico. The purpose of the sampling was to identify radionuclides
potentially present, to quantitatively estimate and compare the amount of
radionuclide uptake at specific locations (Site 2 and Site 3) within a canyon
system (Mortandad Canyon) to an upstream site (Site 1), and to identify the
primary mode (inhalation/ingestion or surface contact) of contamination to small
mammals. Three composite samples of at least five animals per sample were
collected at each site. Pelts and carcasses of the animals were separated and
analyzed independently. In addition, three composite samples were also collected
for plants and sediments at each site. Samples were analyzed for
241Am, 90Sr, 238Pu, 239Pu, and total
U. With the exception of total U, all mean radionuclide concentrations in small
mammal carcasses and sediments were significantly higher at Site 2 than Site 1
or Site 3. No differences were detected in the mean radionuclide concentration
of plant samples between sites. However, some radionuclide concentrations found
at all three sites were higher than regional background. No differences were
found between mean carcass radionuclide concentrations and mean pelt
radionuclide concentrations, indicating that the modes of contamination
(ingestion/inhalation and surface contact) may be equally occurring.

Key words: rodents, plants, sediments, radionuclide concentrations

Poster presentation.

8 • DEVELOPMENT OF POLYHYDROXAMATE CHELATORS FOR APPLICATIONS
TO ACTINIDE REMEDIATION

W.C. Bisset1, O. Zincircioglu1, P.H. Smith2,
and A.S. Gopalan1, 1Department of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, NM, 88003, and
2Los Alamos National Laboratory, Los Alamos, NM, 87545

The goal of our program is to develop cost-effective chelators for the
specific complexation and subsequent removal of actinide ions from soils and
waste waters. In this context, we have synthesized and evaluated the metal ion
binding properties of a number of new polyhydroxamate chelating agents. The
synthesis and binding properties of some polyhydroxamates having the ligand
moieties preorganized around a benzene spacer group has been recently disclosed
(Gopalan et al., in Separations of Elements, Plenum, NY, 1995).
This study has now been extended to acyclic polyhydroxamates, having a diamine
backbone. Simple synthetic strategies towards a number of these new and modified
polyhydroxamates as well as the results of their preliminary binding studies
with metal ions including thorium, iron, uranyl, and lanthanum will be reported.
The goals are to understand the potential cooperativity between the ligand
moieties appended to a diamine spacer group in this class of chelators with
respect to metal ion binding and to develop analogs having higher actinide
affinities and selectivities .

Key words: polyhydroxamate chelators, actinides, remediation, selectivity.

Poster presentation.

9 • DEVELOPMENT OF TAILORED BIOFILTER FOR REMOVAL OF HEAVY
METALS

Z.A. Samani1 and S. Ghosh2, 1Civil
Engineering Department, New Mexico State University, Las Cruces, NM, 88003, and
2Department of Civil and Environmental Engineering, University of
Utah, Salt Lake City, UT, 84102

The release of hazardous heavy metals into soil, surface water, and ground
water is a major concern. Heavy metal contamination is caused by various
industrial activities including the mining, metallurgical, and electroplating
industries. Recent research at University of Utah has shown that specially-grown
biopolymers can be very effective in binding heavy metals. In this research,
heavy metal removal of up to 130% of the dry cell weight was observed. This
binding efficiency is significantly higher than activated carbon. A number of
photosynthetic materials may also be used to remove heavy metals. Recent
research at New Mexico State University has shown that wheat and barley straw
can remove heavy metals up to two percent of the dry weight of straw. This paper
describes a novel approach by combining the two techniques to produce a
bacteria-tailored straw for a more efficient and economical removal of heavy
metals from contaminated water.

Key words: heavy metal, bioremoval, phytoremediation, environment.

Poster presentation.

10 • CS-137 CONTAMINATION MEASUREMENTS OF TECHA RIVER BANK
TERRITORY IN BRODOKALMAK SETTLEMENT

A.V. Chesnokov1, A.P. Govorun1, V.I.
Liksonov1, S.B. Scherbak1, M.V. Ivanitskaya2,
and L.N. Isaeva2, 1RECOM Ltd, str. Schukinskaya, 12-1,
Moscow, 123182, RUSSIA, and 2Rosgidromet, str. Vitebskaya, 15,
Chelyabinsk, 454048, RUSSIA

The Cs-137 contamination mapping (with a scale of 1:2,000) of 1 sq km Techa
river bank territory inside the settlement Brodokalmak is carried out. The
electron maps of Cs-137 contamination distribution of bank landscape are
created. Measuring collimated scintillated detector technique was used for
Cs-137 stock measurements. This method allows for the determination of total
Cs-137 stock and thickness of soil layer containing more than 80% of total stock
in-site. The RKG-09N device was used for these measurements.

It was shown that Cs-137 contamination has a very heterogeneous character and
the stock means achieve 107 Bq/m2 at some places. The
comparison between the above-mentioned technique and traditional probe method
was carried out at specially selected places. The gamma spectrometer laboratory
data have shown a good agreement with site data. Additionally the probes were
investigated to determine the surface soil Sr-90 activity. It was shown that the
Cs-137 contamination correlates with the Sr-90 contamination within the bank
territory of separate settlement. The total Cs-137 stock contained at the
investigated territory is near 6.6x1011 Bq. The estimation of total
Sr-90 stock here is near 2.2x1011 Bq.

Key words: Cs-137 contamination, gamma radiation, beta radiation, mapping,
collimated scintillated detector, probe method.

Poster presentation.

11 • GAMMA LOCATOR TO DETERMINE SPECTRUM CHARACTERISTICS OF
QUANTUM FLUX

A.V. Chesnokov, A.A. Gulyaev, S.M. Ignatov, V.N. Potapov, and L.I. Urutskoev,
RECOM LTD, str. Schukinskaya, 12-1, Moscow, 123182, RUSSIA

The gamma-locator for contamination survey inside the premises connected with
the nuclear production is developed.

The device consists of the detector head and the remote control unit
connected with a cable (>100 m). The detector head (500x500x400 mmxmmxmm,
with weight near 40 kg) is the collimated scintillated gamma detector installed
at the scanning unit. The gamma detector is placed into the lead shielding with
a collimator having an entrance angle near 10º. The detector head is supplied by
TV camera and laser distance device.

The remote control unit provides operation and processing of the acquiring
information.

A gamma detector is based on a system of scintillator CsI(T1) and Si
photodiode. The detector energy resolution (it's near 9% for the radiation of
Cs-137) provides the identification of gamma-radiating isotopes such as Co-57,
Cs-137, K-40, Co-60, I-131, and Eu-154. The gamma locator threshold of
determination is 250 Bq/cm2 for 10 cm3 scintillator and
Cs-137 radiation.

The system allows for measurement of the effective surface activity density
(for Cs-137 radiation) of all premise surfaces and reconstruction of the exposed
dose rate distribution within the volume of investigated space.

Key words: contamination survey, gamma radiation, collimated scintillated
detector, scintillator, photodiode.

Poster presentation.

12 • ESTIMATION OF GEOCHEMICAL BACKGROUND LEVELS FOR
ENVIRONMENTAL STUDIES USING EXISTING DATA SOURCES

F. Luo, J.M. Barker, and C.E. Chapin, New Mexico Bureau of Mines and Mineral
Resources, New Mexico Tech, 801 Leroy Place, Socorro, NM, 87801-4796

Calculation of geochemical background levels for use in environmental
mitigation is always a problem. One of the major impediments is the disparate
data available in widely-scattered source materials. A central database that can
accept data in any form and that can be easily reorganized at will is a tool
that greatly reduces the adverse effects of disparate data.

The New Mexico Bureau of Mines and Mineral Resources, under contract with the
U.S. Bureau of Mines via their Hispanic Association of Colleges and Universities
(HACU) program, has developed a database, the Generalized Data System (GDS),
capable of handling disparate environmental and other data. The GDS can handle
any data, but the initial project is oriented toward environmental activities at
mining sites.

Various data at or near the Kelly lead-zinc mining district, near the town of
Magdalena in west-central New Mexico, were entered into a customized version of
the Paradox relational database used at the core of GDS. Approximately 2,600
data points were used to calculate various background levels using standard
statistical techniques.

The GDS is unique because it is structured to allow easy forming, deleting,
merging, or dividing of data fields. This is a critical feature, not found in
other databases, that allows rapid, efficient organization of disparate data.
These data have formats and other attributes that cannot be entirely anticipated
in pre-defined data fields. Rather, data fields must be defined "on the fly"
during data entry as unexpected data formats appear. The GDS supplies this
capability as its primary design feature.

Key words: background, database, environment, geochemical, mining.

Poster presentation.

13 • ULTRASOUND-MODIFIED CUPRIC ION ADSORPTION ON IRON (III)
FLOCS

H. Campos1 and P.E. Wheat2, 1Environmental
Technology Program, University of Northern Iowa, Cedar Falls, IA, 50614-0421,
and 2Department of Industrial Technology, University of Northern
Iowa, Cedar Falls, IA, 50614-0178

A model system to investigate the ability of intense ultrasound to enhance
the removal of potentially hazardous metallic ions from aqueous solution via
modified iron hydroxide adsorption/coprecipitation has been conducted. The
experimental data indicates that ultrasonic disruption of pre-formed ferric
hydroxide flocs can modify the removal efficiency of metallic ions from aqueous
solution. The methodology is effective over copper to iron molar concentration
ratios ranging from 10-30% and pHs of 7.5-9.5.

Key words: ultrasound, iron (III) hydroxide, co-precipitation, adsorption,
pH.

Poster presentation.

14 • EVALUATING THE BIOACCUMULATION OF HEAVY METALS AND
ORGANICS IN AN AQUATIC ENVIRONMENT

J.L. Regens, K.H. Watanabe, D.G. Hodges, K. Johnson, and C.M. Swalm, Energy
Spatial Analysis Research Laboratory, Tulane University Medical Center, 1430
Tulane Avenue SL-1, New Orleans, LA, 70112-2699

The improper storage, use, or disposal of hazardous substances, especially
heavy metals and chlorinated hydrocarbons, can contaminate an array of
environmental receptors ranging from soils, surface water, and sediments to
ground water. Such contamination may result in health or ecological risks
depending on the specific contaminants-of-concern, their concentrations, and the
existence of active pathways for exposure for human or ecological receptors. As
a result, growing concern about the efficacy of remediation technologies
underscores the need for valid, reliable data emphasizing risk-based site
assessments to delineate the dynamics of pollutant transport and fate. This
poster presents the results of an ongoing study that examines bioremediation and
bioaccumulation of heavy metals and organics in Devil's Swamp, Louisiana.
Primary contaminants-of-concern include arsenic, cadmium, chromium, lead,
mercury, hexachlorobenzene, and hexachlorobutadiene. Contaminant concentrations
in water, sediment, and fish specimens will be presented based on historical
records collected as part of the EPA Superfund listing process as well as data
collected from 1994-1995.

Key words: environmental fate and transport, site assessment, remediation.

Poster presentation.

15 • IMMOBILIZATION OF INDUSTRIAL WASTE IN CEMENT MATRIX

I. Plecaš and A. Peric, Institute of Nuclear Sciences "Vinca," P.O. Box 522,
11001 Belgrade, YUGOSLAVIA

Results are presented of a series of experimental tests performed to
determine the influence of matrix characteristics on the leaching mechanism of
copper aluminum oxychloride immobilized into cement matrices. The objective of
this research was to investigate the leaching mechanism of copper as a
constituent of copper aluminum oxychloride ("CAOX").

Key words: immobilization, cement, leaching rate, diffusion, cumulative
fraction.

Poster presentation.

16 • THE UPTAKE OF STRONTIUM BY CHAMISA (CHRYSOTHAMNUS
NAUSEOSUS) SHRUB PLANTS GROWING OVER A FORMER LIQUID WASTE DISPOSAL SITE AT
LOS ALAMOS NATIONAL LABORATORY

P.R. Fresquez, T.S. Foxx, and L. Naranjo, Jr., Environmental Assessments and
Resource Evaluations Group (ESH-20), Environment, Safety, and Health Division,
MS M887, Los Alamos National Laboratory, Los Alamos, NM, 87545

Chamisa (Chrysothamnus nauseosus) shrub plants growing over a former
lanthanum (40 h half-life) and strontium (90Sr) (28 y half-life)
contaminated liquid waste disposal site (structures were excavated, removed, and
backfilled in 1963) in Bayo Canyon at Los Alamos National Laboratory (LANL) were
collected and analyzed for 90Sr. Surface soil samples (0- to 2-inch
depth) were also collected from below (understory) and between (interspace)
shrub canopies. Chamisa plants growing over the site contained significantly
higher concentrations of 90Sr than a control plant-one plant, in
particular, contained 90,500 pCi 90Sr g-1 ash in
top-growth material. Similarly, soil surface samples collected underneath (avg.
= 115 pCi g-1) and between (avg. = 14 pCi g-1) plants
contained 90Sr above regional upper limit background (0.82 pCi
g-1) and LANL screening action soil levels (5.90 pCi g-1);
this probably occurred as a result of chamisa plant leaf fall contaminating the
soil understory area followed by water and/or winds moving 90Sr to
the soil interspace areas. Although some soil-surface migration of
90Sr has occurred, the level of 90Sr in sediments
collected downgradient of the site at the Bayo Canyon/New Mexico State Road 4
intersection (0.10 pCi g-1) was still within the regional upper limit
background sediment concentration (0.87 pCi g-1).

Key words: radionuclides, 90Sr, vegetation, contamination,
transport.

Poster presentation.

17 • ENVIRONMENTAL PROGRAM AT JACKSON STATE UNIVERSITY

P.-C. Yuan, Hazardous Material Management Program, Jackson State University,
Jackson, MS, 39217

Jackson State University is one of the Historically Black Colleges and
Universities (HBCU) in the South. The School of Science and Technology includes
seven different departments. The Hazardous Material Management program started
in 1988 under the Department of Technology and Industrial Arts. In 1994 the
Institute of Higher Learning approved the master degree for Hazardous Materials
Management. In the Biology department, the school offers the master degree and
the only approved Ph.D. degree in Environmental Science in Mississippi since
1990. Recently, the Department of Technology and Industrial Arts received a $1.5
million grant from the National Institute of Health for the next five years as a
environmental training center for minorities, Indian Tribes, and the general
public. Training courses emphasize lead abatement, hazardous waste work at
hazardous waste site at different levels, such as worker, trainer, supervisor,
and technician.

Key words: minority, training, hazardous material, lead abatement.

Poster presentation.

18 • MICROBIAL POPULATION DYNAMICS AND BIODEGRADATION
KINETICS OF ORGANIC POLLUTANT MIXTURES

J.D. Rogers1, N.M. DuTeau2, S.J. Chacko1,
and K.F. Reardon1, Departments of 1Chemical and
Bioresource Engineering and 2Microbiology, Colorado State University,
Fort Collins, CO, 80523-1370

Contamination of ground water and soil is most often a mixture of pollutants,
and these mixtures are transformed by mixtures of microorganisms. However, few
quantitative studies of biodegradation kinetics have addressed these complex
mixture aspects. The goal of the work presented in this poster is to measure
changes in both the chemical and microbial concentrations during mixed
culture-mixed pollutant biodegradation.

A simple two-species microbial system was chosen as the first test of our
methods. Pseudomonas putida F1 and P. sp. JS150 are capable of
growth on various aromatic hydrocarbons; however, P. sp. JS150 has a
wider substrate range that includes chlorobenzene. Species-specific genetic
markers were developed for both organisms. These markers were used to develop
and test several molecular techniques for quantitation of the population of each
species in biodegradation experiments. Conventional differential plating
techniques were used as a validation for each method screened. Mathematical
modeling was used to determine the relationships between the composition of the
microbial and pollutant mixtures and to describe the interactions between the
two species. The population dynamics of the mixed microbial population was found
to be related to the changes in the composition of the pollutant mixture, and
interaction between the two species was apparent. These results suggest that
single species/single pollutant biodegradation kinetics are not readily extended
to more complex systems.

Key words: biodegradation, mixtures, kinetics, populations.

Poster presentation.

19 • ASSESSMENT OF BRINE CONTAMINATION OF SURFACE WATERS AND
SOIL USING ION-SELECTIVE ELECTRODES

R. Yates1, T.M. Harris2, and K. Sublette1,
1Department of Chemical Engineering and 2Department of
Chemistry, University of Tulsa, 600 S. College Avenue, Tulsa, OK, 74104

The contamination of soil, surface waters, and ground water is a common
environmental problem associated with handling and disposal of brine in oil
field operations. The primary components of this salt contamination may be
quantified by more than one analytical method; however, the use of direct
potentiometry with ion-selective electrodes is most attractive because it is
reasonably accurate, fast, and may even be used in the field. In this study, a
series of pond water samples and extracts from brine-contaminated soils were
analyzed using a sodium ion electrode and a "hardness" electrode, and the
results were compared with those obtained by atomic absorption
spectrophotometry. Also, chloride measurements made using a chloride electrode
were compared to those obtained with an amperometric technique.

Key words: soil, surface water, salt contamination, analysis, ion-selective
electrodes, oil field operations.

Poster presentation.

20 • CORRELATION OF SURFACE WATER QUALITY AND OIL PRODUCTION
IN THE TALLGRASS PRAIRIE PRESERVE

R. Yates1, K. Sublette1, T. Harris2, and B.
Tapp3, 1Department of Chemical Engineering,
2Department of Chemistry, and 3Department of Geosciences,
University of Tulsa, 600 S. College Avenue, Tulsa, OK, 74104

The contamination of soil with salt is a common environmental problem
associated with handling and disposal of brine co-produced with petroleum. The
salt is relatively mobile, and thus may pose a threat to nearby surface waters.
There are over 100 ponds within the Tallgrass Prairie Preserve, a 40,000 acre
preserve operated by The Nature Conservancy. Oil and gas have been produced from
shallow reservoirs beneath this area for over 80 years. Damage to vegetation
(and subsequent erosion) is evident at several production sites. The objective
of this study was to correlate the chemical composition of the water in each of
the ponds with production sites and the surrounding topography.

Key words: surface water, salt contamination, oil production, Tallgrass
Prairie Preserve.

Poster presentation.

21 • RDX AND HMX SORPTION IN THIN DISK SOIL COLUMNS

D.M. Townsend1, T.E. Myers1, and D.D.
Adrian2, 1U.S. Army Engineer Waterways Experiment Station,
3909 Halls Ferry Road, Vicksburg, MS, 39180-6199, and 2Louisiana
State University, Baron Rouge, LA, 70803

Subsurface contamination by 2,3,5-trinitro-1,3,5-triazine (RDX) and
oxyhydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) has prompted remediation
and containment efforts at many Army installations. Contaminant transport
modeling, a time- and cost-effective tool for comparing various remediation
alternatives, is hampered by lack of information on the significance of RDX and
HMX disappearance and sorption in soils.

This study was conducted to estimate RDX and HMX disappearance and sorption
parameters from breakthrough curves (BTCs) for three soils-a silt loam, a
clay-rich soil, and Ottawa sand. Thin disk soil columns (0.32 cm soil length)
were used to obtain RDX and HMX BTCs. Effluent RDX and HMX concentrations were
analyzed as a function of pore volumes eluted.

The thin disk columns produced approximately symmetrical RDX and HMX BTCs for
each soil. The BTCs were modeled assuming complete-mix, first-order
disappearance, and linear equilibrium sorption. This model produced excellent
curve fits, with only slight discrepancies between the model and the observed
data. Good mass balances were observed for each soil for both RDX (102.0 to
105.0 percent) and HMX (101.6 to 110.2 percent).

Both RDX and HMX tended to sorb weakly to the soils used in this study.
Linear equilibrium distribution coefficients (Kd) for RDX ranged from
1.35 to 5.7 l/kg. Linear equilibrium distribution coefficients for HMX ranged
from 1.45 to 8.5 l/kg. Mass balance analysis indicated that disappearance
(transformation, irreversible sorption, etc.) of RDX and HMX was negligible in
this study.

Key words: RDX, HMX, ground water, sorption, transport.

Poster presentation.

22 • PHYTOREMEDIATION OF LEAD-CONTAMINATED SOILS BY NATIVE
SPECKS AT AN ABANDONED MINE SITE IN UTAH

S.P. Klassen, J.E. McLean, P.R. Grossl, and R.C. Sims, Utah Water Research
Laboratory, Utah State University, Logan, UT, 84322-8200

Heavy metal uptake by native vegetation was investigated at an abandoned mine
site contaminated with high levels of Pb, Zn, and Cd. Two tree and one sedge
species were identified as possible hyperaccumulators of lead at this site.
Hydroponics and soil column studies are currently in progress to further examine
the accumulation of lead in these species. A comparison of different populations
of seedlings will be made to determine if mine site populations are distinct
with respect to lead tolerance and accumulation. The potential for
phytoremediation of lead-contaminated sites is examined.

Key words: phytoremediation, lead, mine soils, trees, sedge.

Poster presentation.

23 • EFFECT OF POPLAR RHIZOSPHERE ON MICROBIAL POPULATIONS
THAT DEGRADE PRIORITY POLLUTANTS

L. Foster, M.E. Vermace, and P.J.J. Alvarez, The University of Iowa,
Department of Civil & Environmental Engineering, Iowa City, IA, 52242

Phytoremediation, the use of plants to remove environmental pollutants from
contaminated sites, holds great promise as a low-cost remedial approach. Indeed,
the ability of poplar (Populus spp) trees to enhance site remediation is
well documented. Nevertheless, the rational development of this remedial
technique is limited by our incomplete understanding of the specific remediation
mechanisms. While poplars have been shown to remove pollutants by vegetative
uptake and in-plant degradation, very little is known about the effect that the
poplar roots have on microbial degradation activity and diversity. The purpose
of this project was to investigate the relative abundance of indigenous
microorganisms in the poplar rhizosphere that are capable of degrading priority
pollutants.

Microbial populations from the root zone of 7-year-old poplar trees were
characterized by concentration and catabolic capacity. The concentrations of
total heterotrophs, denitrifiers, pseudomonads, BTX degraders, and
atrazine degraders were determined using appropriate Most Probable Number (MPN)
techniques. For each of these phenotypes, the MPN concentrations in three
rhizosphere soil samples were compared to those in three surrounding (control)
soil samples. The tested soils (collected from a depth of about 150 cm) had
prior exposure to nitrate, but no known prior exposure to BTX or atrazine.
Whether MPN differences were significant was evaluated statistically using
Student's T-test. Rhizosphere and surrounding soils were also examined for
microbial diversity. This analysis consisted of quantifying the number of
(different) colony types, based on the morphology of microbial colonies grown on
agar plates.

The number of colony types (NCT) grown on agar plates were similar for
rhizosphere (NCT were 6, 7, and 5) and surrounding soils (NCT were 6, 2, and
10), indicating that the diversity of culturable heterotrophs was similar for
both soils. Nevertheless, the concentrations of all types of organisms
investigated were significantly higher in the rhizosphere than in the
surrounding soils. For total heterotrophs, the differences were significant at
the 95% level. For pseudomonads, denitrifiers, and BTX degraders, the
difference was significant at the 90% level. When the abundance of individual
phenotypes is expressed as a fraction of the total heterotrophs, the relative
concentrations of pseudomonads and BTX degraders in the rhizosphere are
also greater than in surrounding soils at the 90% significance level. In
addition, only one of the six soil samples (i.e., a rhizosphere sample)
exhibited atrazine degradation activity. These results suggest that the root
zone may exert preferential selection for desirable phenotypes. Apparently, the
poplar rhizosphere constitutes an enhanced growth environment for a wide variety
of beneficial microorganisms.

To further explore the mechanisms by which the poplar rhizosphere enhances
microbial biodegradation activity, poplar root exudates were tested as inducers
of toluene dioxygenase (TDO) in Pseudomonas putida F1 (PpF1). TDO is an
environmentally-relevant enzyme because of its ability to degrade numerous
priority pollutants, including benzene, toluene, and trichloroethylene (TCE).
Preliminary ELISA results indicate that an as yet undetermined component(s) of
poplar root exudates induces TDO in PpF1.

In summary, this work suggests that poplar root exudates might enhance the
viability of beneficial microorganisms and enhance natural bioremediation
processes. The proliferation of desirable phenotypes in the root zone would be
conducive to enhanced contaminant removal rates, and thus, reduced duration (and
cost) of site remediation.

Key words: atrazine, BTX, biodegradation, rhizosphere, root exudates, toluene
dioxygenase.

Poster presentation.

24 • TRACER TESTS FOR EVALUATING AIR SPARGING AND IN-WELL
AERATION TREATMENT SYSTEMS

J.S. Berkey, W.J. Doucette, and R.R. Dupont, Utah Water Research Laboratory,
Utah State University, Logan, UT, 84322-8200

Tracer tests are being conducted in support of an upcoming field project
designed to evaluate the effectiveness of air sparging and in-well aeration for
remediation of a gasoline-contaminated site. Laboratory simulations of the
treatment systems are being performed in porous media, filled stainless steel
tanks with clean and contaminated water. The utility of several tracers,
including sulfur hexafluoride, helium, bromide, and fluorescein, for the
evaluation of flow patterns, flow rates, and volumes of influence will be
investigated. Bromide and dye tracers will be monitored in the saturated zone,
while sulfur hexafluoride and helium will be monitored in both the saturated and
unsaturated zones. Results from the laboratory studies will be used to compare
the performance of various tracer substances, compare the hydraulic effects of
the air sparging and in-well aeration systems, and optimize experimental design
for the field scale tracer tests.

Key words: tracers, ground water remediation, air injection, in-well
aeration, air sparging.

Poster presentation.

25 • LABORATORY EVALUATION OF OXYGEN TRANSFER RATES AND
TRANSFER EFFICIENCIES OF AIR SPARGING AND IN-WELL AERATION

S. Miller, Utah Water Research Laboratory, Utah State University, Logan, UT,
84322-8200

Two methods for the introduction of oxygen into an aqueous environment were
evaluated in a laboratory setting: air sparging and in-well aeration. Air
sparging is a remediation technique in which air is introduced directly into a
formation to produce air/soil contact and stripping of contaminants. In-well
aeration provides a technique for the movement and air stripping of contaminated
ground water through the action of an air-lift pump inside the well head. These
two air-injection methods were examined in a clean water system. Measurements
were taken to determine the effect each transfer method had on the distribution
and mass transfer rate of oxygen in laboratory-scale systems. The ASCE standard
method for oxygen transfer rate determinations in a clean water system was the
experimental method employed in the study. This is the initial portion of a
larger HSRC-funded project in which oxygen transfer in saturated soils in
laboratory and field-scale systems will be examined. For comparability with the
field study, laboratory-scale air flow rates were scaled from those used in the
field portion of the project. Lab oxygen transfer rates and transfer efficiency
results from the two air-injection systems will be presented and contrasted, and
extension of these findings to field-scale applications will be made in this
poster presentation.

Key words: air sparging, ground water remediation, oxygen transfer, lab-scale
systems, dissolved oxygen, oxygen transfer, in-well aeration.

Poster presentation.

26 • BIODEGRADATION OF CHELATING AGENTS USED FOR METAL
REMOVAL FROM CONTAMINATED SOILS

T. Regmi1, S.K. Banerji1, and A. Hong2,
1Department of Civil Engineering, University of Missouri, Columbia,
MO, 65211, and 2Department of Civil Engineering, University of Utah,
Salt Lake City, UT, 84112

Effectiveness of chelating extraction for removal of metals from contaminated
soils has been investigated by many researchers. The results have shown that
this method can effectively extract metals from soil-water phase and precipitate
them out in form of hydroxides and hydroxy-carbonates while the chelators can be
reused.

The chelating compounds used for heavy metals extraction from contaminated
soils are organic compounds and are subject to biodegradation under field
conditions. During the chelating extraction with recycling of chelating agents,
naturally-occurring microorganisms in the soil can essentially develop an
enzymatic system capable of metabolizing these chelating compounds, thereby
reducing the amount present in the solution for successive reuse.

Six chelating compounds have been selected for studying chelating extraction
of contaminated soils. At this time the biodegradabilities of three of these
compounds have been evaluated. These compounds are Ethylenediaminetetraacetate
(EDTA), 2,6-Pyridinedicarboxylic acid (PDA), and S-Carboxymethyl-L-Cysteine
(SCMC).

EDTA was degraded up to 2 mM equally with and without soil exhibiting strong
inhibition at higher concentrations. Biodegradation rates for EDTA have been
determined to be very low

PDA was metabolized by acclimated mixed culture as a sole source of carbon
and energy equally with and without soil. PDA was completely eliminated from
solution at concentrations up to 6 mM within 36 hours, showing no inhibition at
these high concentrations.

SCMC has also been found to be degraded by acclimated mixed culture. The data
generated will be used to determine kinetic parameters for degradation of these
compounds.

Key words: soil remediation, chelating agents, chelating extraction,
biodegradation, enzymatic inhibition.

Poster presentation.

27 • TREATMENT OF WOOD PRESERVATIVE-CONTAMINATED SOILS AS
AFFECTED BY ELECTRON ACCEPTOR ADDITION

K.C. Nieman, R.C. Sims, R.A. Petrie, and J.L. Sims, Division of Environmental
Engineering and Utah Water Research Laboratory, Utah State University, Logan,
UT, 84322-4110

Two wood preservative-contaminated soils from two Superfund sites, containing
polycyclic aromatic hydrocarbons (PAH) and pentachlorophenol (PCP), were treated
using oxygen as the electron acceptor and oxygen plus manganese as electron
acceptors. Poisoned controls were used to evaluate the roles of biotic versus
abiotic reactions. Differences among treatments were measured by determining
specific parent compounds and biotransformation intermediates. Indicator
compounds were measured in: (1) water soluble extracts for evaluation of
chemical leaching, and (2) solvent extracts for evaluation of soil-associated
chemicals. In addition, the Microtoxä assay was used to evaluate water soluble
(leachate) toxicity. Effectiveness and economics with regard to treating wood
preservative-contaminated soil by addition of manganese were evaluated.

Key words: bioremediation, wood preservative, land treatment, polycyclic
aromatic hydrocarbons, pentachlorophenol.

Poster presentation.

28 • A BATCH REACTOR FOR CONTROL OF Eh, pH, AND TEMPERATURE
OF SUBSURFACE AQUEOUS SYSTEMS

R.A. Petrie1, R.C. Sims1, and P.R. Grossl2,
1Division of Environmental Engineering and Utah Water Research
Laboratory, Utah State University, Logan, UT, 84322-4110, and
2Department of Plant Soils and Biometerology, Utah State University,
Logan, UT, 84322-4820

Oxidation-reduction (redox) reactions influence the fate, transport, and
transformation of organic chemicals in subsurface environments. Lack of
availability and complex operation of reactors that are available regarding the
simulation of the subsurface environment at a particular site with regard to
redox, pH, and temperature present significant constraints to current attempts
to understand subsurface reactions and to develop remediation management
decisions.

This poster presents the design and operation of a simple bench-scale batch
reactor that is used to control redox potential, pH, and temperature of an
aqueous subsurface system. The reactor can be used to maintain environmental
conditions for evaluation of intrinsic remediation or can be used to adjust
environmental conditions to a new steady state for evaluation of the effect of
engineered remediation on a subsurface system, as well as to evaluate
requirements for chemical addition to adjust subsurface environments to
different environmental values. The reactor can operate over a wide range of
redox potential values, from -400 mV to +400 mV, and pH values. Parameters can
also be controlled for small incremental changes. The redox potential can be
controlled within 1-2 mV, pH within 0.05-0.1 unit, and temperature within 0.1°C
for weeks or months. Results for the reactions and fate of subsurface minerals
and pentachlorophenol at different redox and pH values will be presented.

Key words: redox, pH, reactor.

Poster presentation.

29 • HEAVY METALS REMOVAL FROM CONTAMINATED WATER SOLUTIONS

Z. Lewandowski, F. Roe, and M.T. Fernandez, Center for Biofilm Engineering,
Montana State University, Bozeman, MT, 59717

As a result of an ongoing project, we have developed a novel technology which
has potential for removal and recovery of heavy metals from dilute aqueous
solutions. Our technology includes three consecutive processes: metal
preconcentration, metal stripping, and metal recovery. In the first step the
metals are bound to biopolymers from dilute solutions. In the second step the
metals are desorbed by shifting chemical equilibrium to form concentrated
solutions. In the third step the metals are recovered from the concentrated
solution by electroplating. The second and third steps can be accomplished
simultaneously. In effect the biopolymer is regenerated and the metals are
removed and recovered in metallic form that is easy to handle and is not toxic.
The regenerated biopolymer is recycled to the process and used many times.
Additionally, the metals can be removed selectively, by selective
electroplating. This is a major advantage in cases where a metal of high market
or strategic value is recovered from a mixture with other metals.

Metal preconcentration was studied in detail using absorption of metals by
alginate gel beads. Mixtures of copper and zinc ions in solutions with pH
ranging from 2.6-5.4 were tested. Binding group density of alginate gel, and
binding stability constants of the respective metals in solution were calculated
from experimental data. Using these parameters a new model was developed to
predict the equilibrium concentrations of copper, zinc, and hydrogen ions in the
presence of alginate gel beads. The experimental data closely fit the extended
Langmuir model allowing binding group density and stability constants to be
determined. The equilibrium concentrations of each species predicted by the new
model agree well with experimental concentrations.

Key words: heavy metal, water, metal recovery, metal stripping, metal
preconcentration.

Poster presentation.

30 • ASSESSMENT OF NATURAL ATTENUATION OF HEXAVALENT
CHROMIUM IN GROUND WATER: USCG SUPPORT CENTER, ELIZABETH CITY, NORTH CAROLINA

R.W. Puls and C.J. Paul, National Risk Management Research Laboratory, USEPA,
P.O. Box 1198, Ada, OK, 74820

The natural attenuation of hexavalent chromium has been evaluated at a field
site near Elizabeth City, North Carolina, to provide guidance on this type of
site assessment for remedial decision-makers. Laboratory and field test methods
are presented together with results for this particular site. Geochemical
indicators important for assessment of natural attenuation are listed and
discussed. The importance of site characterization is emphasized to support
"natural attenuation" as a remedial alternative or as a complement to other
remedial measures.

(This is an abstract of a proposed presentation and does not necessarily
reflect EPA policy.)

Key words: natural attenuation, chromium, chromate, ground water remediation,
site assessment, site characterization.

Poster presentation.

31 • CELLS ON FOAM AND FIBER

R. Clyde, Clyde Engineering, P.O. Box 740644, New Orleans, LA, 70174

When a steel screen is put around foam, it is made heavier so it can be
fluidized. Cells grow on the foam.

When the bacterium Zymomonas mobilis is put on Tyvek fiber, toxic
metals such as lead and chromium can be removed from wastewater in two seconds.

When a rotary biological contactor is run half full and a light shone in the
top, the light hits a thin moving film. In other photo reactors, colored or
turbid solution blocks the light.

Ethanol can be produced from sugar in 15 minutes.

Corrugated fibers can be used. Old cardboard boxes are readily available.
Calcium magnesium acetate, a non corrosive road deicer, can be made with cells
on rotating fibers.

Key words: fiber, foam, metal, reactor.

Poster presentation.

32 • BIOAVAILABILITY AND RISK ASSESSMENT OF CONTAMINATED
SOIL USING AQUEOUS AND SOLVENT EXTRACTION

N. Bordelon, H. Huebner, K. Washburn, L. He, K.W. Brown, and K.C. Donnelly,
Department of Veterinary Anatomy and Public Health, Texas A&M University,
College Station, TX, 77843-4458

Contaminated media at Superfund sites typically consist of complex mixtures
of organic and inorganic chemicals. While a site may host a limited number of
inorganic chemicals, literally thousands of organic chemicals may be present.
These mixtures are difficult to characterize, both analytically and
toxicologically, especially the complex mixtures of polycyclic aromatic
hydrocarbons (PAHs). The current approach to risk assessment assumes that all
contaminants are available for human uptake. EPA protocol uses solvent
extraction to remove chemicals from the soil as a basis for estimating risk to
the human population. However, contaminants that can be recovered with a solvent
extract may not represent chemicals that pose a threat to human health via
leaching or absorption. Chemicals that are tightly bound to the soil are
unlikely to migrate to ground water. A system using aqueous extraction provides
a more realistic picture of the threat contaminated soils pose to the human
population. A preliminary study was conducted with coal tar-contaminated soil
spiked with benzo(a)pyrene (BaP), a known animal carcinogen, and trinitrotoluene
(TNT). Samples were extracted with methylene chloride (MeCl2) or
water titrated to pH 2 and pH 7. The samples were tested for genotoxicity using
Salmonella typhimurium strain TA98 with and without metabolic activation.
Chemical analysis demonstrated 100% recovery of the solvent extract and up to
36% and 42% recovery for aqueous extraction at pH 2 and pH 7, respectively. In
performing a risk assessment based on chemical analysis, all samples exceeded
1E-6; however, the risk associated with the solvent extract (2.23E-5) was almost
one order of magnitude higher than the aqueous extract (pH 2: 3.15E-6 and pH 7:
5.21E-6). These results differ from those obtained through bioassay-based risk
assessment. The aqueous extract at pH 7 was genotoxic with a specific activity
of 98 net revertants, followed by solvent extract (41 revertants) and aqueous
extract at pH 2 (13 revertants). The results indicate that aqueous extraction
provides a complementary tool to solvent extraction in performing risk
assessments, as well as for remediation assessment. Aqueous extraction takes
into consideration the bioavailability of contaminants in the soil giving a more
accurate estimate of what contaminants are of major concern.

(This research was supported by NIEHS Grant No. P42ES04917.)

Key words: aqueous extraction, solvent extraction, risk assessment,
bioavailability.

Poster presentation.

33 • SOIL SORPTION AND PAH SOLUBILITY ENHANCEMENT USING
SURFACTANTS

J. Lay, S.K. Banerji, and R.K. Bajpai, Department of Civil Engineering,
University of Missouri-Columbia, E3502 EBE, Columbia, MO, 65211

Synthetic surfactants have been successfully shown to enhance hydrophobic
organic compound (HOC) bioavailability by increasing the HOC aqueous solubility.
HOC solubility is greatly enhanced when the bulk solution surfactant
concentration is above the CMC. Sorption of surfactant onto soils, though,
results in a decrease of available surfactant for micellar solubilization of
HOCs. The balance between surfactant sorption onto soils, HOC incorporation in
surfactant micelles, and HOC sorption on soil depends upon a number of factors,
including the surfactant type and concentration, the nature of the soil, the
temperature, and the nature of the HOC.

In this study, three nonionic surfactants (Tween 80, Triton X-100, and Triton
X-165), one anionic surfactant, and a cosolvent (methanol) have been used to
enhance the solubilization of PAHs and PCP. Other variables used in testing
include five soils (including an aged soil), two soil slurry concentrations (10%
and 20% w/w), and three temperatures (15°, 25º, and 35ºC).

Adsorption isotherms and PAH/PCP solubility enhancement characteristics have
been evaluated. Relationships between the soil organic content, surfactant
partition coefficients, and octanol/water partition coefficients have been
quantified in an effort to describe the solubility enhancements in soil
slurries.

Key words: isotherms, adsorption equilibrium, aged soil.

Poster presentation.

34 • BIODEGRADATION OF SEVERAL SOLUBILITY ENHANCES BY
ACTIVATED SLUDGE AND AN ENRICHED CULTURE

J. Gu, S.K. Banerji, and R.K. Bajpai, Department of Chemical Engineering,
University of Missouri-Columbia, W2030 EBE, Columbia, MO, 65211

Use of solubility enhances such as surfactants and cosolvents has often been
proposed to increase the rate of biodegradation of sorbed hydrophobic organic
chemicals. Bioremediation engineers are thus faced with the questions of
microbial toxicity and metabolization of the solubility enhances by
microorganisms. In this study, three commercial nonionic surfactants (Tween 80,
Triton X-100, and Triton X-165) and one cosolvent (methanol) have been evaluated
for their effects on microbial growth and their biodegradation.
Laboratory-cultivated activated sludge starting from the local Municipal Waste
Treatment Plant and an enriched culture isolated from contaminated soil from a
wood-treatment site were grown in baffled shake-flasks in the presence of
different concentrations of the solubility enhances. Cell growth as well as
surfactant concentrations were monitored. The results of these studies will be
presented. These results are intended for use as a guideline for scale-up of
soil-slurry reactors.

Key words: biodegradation, surfactants, methanol, Tween 80, Triton.

Poster presentation.

35 • AN EXPERIMENTAL INVESTIGATION OF THE VOLATILIZATION OF
BINARY NONAQUEOUS PHASE LIQUID MIXTURES IN UNSATURATED POROUS MEDIA

C. Gaither and L.M. Abriola, Department of Environmental and Water Resources
Engineering, University of Michigan, Suite 181 EWRE Building, Ann Arbor, MI,
48109-2125

In this research, the volatilization of nonaqueous phase liquid (NAPL)
residuals entrapped in unsaturated sandy porous media is investigated. The
compounds studied are representative of those NAPLs commonly found at many
contaminated ground water sites. These organic contaminants pose a known human
health risk, either through ingestion or exposure to contaminated vapors. This
research investigation is designed to provide information on NAPL volatilization
rates, which will facilitate more accurate exposure assessment and more accurate
predictions of soil vapor extraction remediation performance.

NAPL contaminants are often released to the subsurface as mixtures of organic
compounds. In this work, experiments are designed to study volatilization of
binary NAPL mixtures. This study follows previous investigations in our
laboratory into the volatilization of single component NAPLs in unsaturated
sandy media. Binary mixtures were created from the compounds styrene, toluene,
and tetrachloroethylene. Residual water and NAPL mixture saturations were
emplaced in one-dimensional columns, packed with Wagner sand. Volatilization of
the NAPL mixtures was then observed using prepurified nitrogen as the carrier
gas at pore velocities approximating field soil vapor extraction operations. The
influence of variations in both carrier gas flowrate and NAPL mixture
composition on volatilization mass transfer was explored. In addition, carrier
gas flow interruptions were used to examine mass transfer rate limitations
associated with long-term removal.

Contaminant vapor phase effluent concentration measurements during initial
volatilization and later periods of concentration decline are used to evaluate
the utility of Raoult's law to predict volatilization behavior. The
applicability of a modified Sherwood correlation (Wilkins et al., 1995)
developed for NAPL-vapor phase mass transfer in single component systems is also
evaluated in the context of binary mixtures.

Funding for this research is provided by the National Institute of
Environmental Health Sciences under Grant #ES04911.

Key words: nonaqueous phase liquids, volatilization, unsaturated zone
transport.

Poster presentation.

36 • IMPROVED RECOVERY OF HEAVY METALS AND CHELATING AGENTS
FOLLOWING EXTRACTION FROM CONTAMINATED SOIL

A. Hong and C. Li, Department of Civil and Environmental Engineering,
University of Utah, Salt Lake City, UT, 84112

The use of chelating agents in extracting heavy metals from contaminated soil
is seen as a remediation technique. Although strong metal-complexing chelating
agents have higher extraction and, therefore, remediation potential, they are
more difficult to recover and reuse. Chelating agents having moderate strength
in metals complexation were found to be more amenable to their subsequent
recovery and reuse. In order to make full use of the strong chelating agent such
as EDTA, improved recovery technique must be available. This paper will focus on
those strongest chelating agents and will report efforts and results in their
recovery and reuse.

Key words: heavy metal, soil remediation, chelating extraction, recovery.

Poster presentation.

37 • EXPERIMENTAL OBSERVATION OF TETRACHLOROETHENE TRANSPORT
BEHAVIOR IN AN UNSATURATED SAND COLUMN

C. Yu and M.H. Conklin, Department of Hydrology and Water Resources, The
University of Arizona, Tucson, AZ, 85721

Transport of tetrachloroethene (PCE) through variably saturated sand was
studied in an intermediate-scale (1.05 m length and 0.1 m diameter) stainless
steel column. This column was packed with silica sand and instrumented with 10
gas sampling probes, 10 water sampling probes, 10 tensiometers, 10 gas ports,
and 10 sets of TDR (Time Domain Reflectometry) probes. Key questions addressed
by this research were 1) is mass transfer of PCE between liquid and gas phases
rate limited? 2) can hysteretic hydraulic properties be neglected in describing
transport of dissolved PCE through the column? 3) is the transport behavior of
PCE independent of initial flow (or water content) conditions? and 4) can a
simple steady-state model be used to simulate PCE transport under transient flow
conditions?

Key words: vadose zone, transport, tetrachloroethene, scale.

Poster presentation.

38 • ADSORPTION OF ORGANIC POLLUTANT MOLECULES TO MINERAL
SURFACES

N.E. Takach and K. Meredith, Department of Chemistry, University of Tulsa,
Tulsa, OK, 74104

A preliminary investigation was conducted on the suitability of the dynamic
Wilhelmy plate technique for examining the adsorption of different classes of
organic pollutant molecules to the surfaces of mineral thin sections. Plates
(thin sections) made both from marble and from quartzite were examined and
1,4-dinitrobenzene represented the first class of pollutant studied:
nitroaromatics. Plates of each mineral type were completely immersed in toluene
solutions of 1,4-dinitrobenzene for varying periods of time before they were
passed into and out of aqueous phases during the Wilhelmy experiments.
Magnitudes and changes in adhesion tensions were used to quantify the strength
and persistence of adsorption.

Key words: nitroaromatics, adsorption, mineral surfaces, organic pollutants,
Wilhelmy technique.

Poster presentation.

39 • OPTIMIZING TNT DESTRUCTION IN CONTAMINATED WATER AND
SOIL BY FENTON OXIDATION

M. Arienzo, S.D. Comfort, P.J. Shea, and Z.M. Li, Department of Agronomy,
University of Nebraska, Lincoln, NE, 68583-0915

The Fenton reagent (H2O2 and Fe2+)
represents one of the simplest and most effective oxidation technologies
available for remediating munitions-contaminated soil and water. Previous
research on Fenton oxidation using FeSO4 and
H2O2 has shown that destruction of recalcitrant organics
is optimum at pH 3.0, but can also be efficient at higher pH in the presence of
iron-complexing ligands. To improve the process of TNT destruction in water,
ferrous oxalate (FeOx) was substituted for FeSO4 and used in
combination with H2O2 to initiate Fenton oxidation. The
effects of FeOx concentration and pH were determined. TNT destruction time was
20 min to 2 h, depending on the amount of iron present. These high destruction
rates may be explained in part by the continuous source of Fe2+
provided by the iron (II)-oxalate. Adjusting solution pH had little effect on
reaction kinetics. This may be due to an acidifying effect of FeOx +
H2O2 on the TNT solution, since pH decreased to 3.0 within
minutes of initiating the reaction. The effects of FeOx +
H2O2 in TNT-contaminated soil slurries will be reported.
Preliminary results indicate that use of FeOx may increase the efficiency of TNT
destruction in contaminated water and soil.

Key words: trinitrotoluene, Fenton oxidation, remediation.

Poster presentation.

40 • FENTON OXIDATION OF TNT IN SOIL SLURRIES AS INFLUENCED
BY TEMPERATURE, DISSOLVED ORGANIC MATTER, AND CLAY MINERALS

Z.M. Li1, P.J. Shea1, S.D. Comfort1, T.C.
Zhang2, and L.E. Erickson3, 1Department of
Agronomy, University of Nebraska, Lincoln, NE, 68583-0915,
2Department of Civil Engineering, University of Nebraska, Omaha, NE,
68182-0178, and 3Department of Chemical Engineering, Kansas State
University, Manhattan, KS, 66506-2502

TNT-contaminated soil and water is an environmental problem at sites where
munitions were formerly manufactured, stored, or demilitarized. Our previous
research demonstrated that Fenton oxidation effectively destroyed TNT in aqueous
extracts of contaminated soil. However, direct application of the Fenton
technique to destroy TNT in a soil slurry system would be more efficient and
likely more cost-effective. Experiments were conducted to determine Fenton
oxidation of TNT in soil slurries. The effects of temperature, dissolved organic
matter (DOM), and clay minerals on oxidation efficiency were also determined.
Results indicate that Fenton oxidation can effectively destroy TNT in a soil
slurry containing 4,875 mg TNT kg-1 (1:5 w/v soil:H2O);
this process was more efficient at 45ºC than 23ºC. DOM (humic and fulvic acids)
had little effect on the total amount of TNT destroyed within 24 h, although a
possible catalytic effect of fulvic acid was observed. Montmorillonite and
kaolinite differed in their effects on TNT oxidation. Adding a small amount of
montmorillonite (0.1-1% w/v) appeared to catalyze TNT destruction in solution,
but as the amount of clay was increased (>1% w/v), adsorption of TNT slowed
the process. Kaolinite exhibited minimal adsorption of TNT, but slowed TNT
oxidation, possibly by quenching reactive free radicals at the mineral surface.
Data were fitted to a two-compartment model to predict TNT destruction by Fenton
oxidation in soil slurries.

Key words: trinitrotoluene, Fenton oxidation, dissolved organic matter, clay
minerals, remediation.

Poster presentation.

41 • SIMULATION OF WASTE-GENERATING CHARACTERISTICS DURING
START--UP OF A REACTOR NETWORK UNDER NONISOTHERMAL CONDITIONS

B.B. Patel and L.T. Fan, Department of Chemical Engineering, Kansas State
University, Manhattan, KS, 66506

During start-up of a large-scale reactor network, a large amount of an
off-spec product is often generated; such a product does not meet the product
specifications and thus should be regarded as waste to be treated or
reprocessed. Moreover, if a hazardous or toxic component is contained in the
product, its accumulation during start-up poses environmental or health risk.
Naturally, it is highly desirable that the generation and accumulation of the
off-spec product be minimized. To devise an optimal strategy or strategies for
accomplishing this requires understanding of the process network's transient
behavior for various modes of start-up.

For illustration, the transient and waste-generating characteristics during
start-up of a system comprising three continuous-stirred tank reactors connected
in series are examined in the present study. Four modes of start-up are
considered under nonisothermal conditions involving several simultaneous and/or
sequential chemical reactions of different orders.

Key words: start-up, reactor network, hazardous waste, off-spec product.

Poster presentation.

42 • CADMIUM, COPPER, AND ZINC ACCUMULATION IN TRANSGENIC
AND NON-TRANSGENIC TOBACCO PLANTS

N.A. Yancey1, J.E. McLean1, R.C. Sims1, P.
Kotrba2, M. Mackova2, T. Macek3, W.
Scouten4, A Singh-Cundy5, and M. Truksa6,
1Utah Water Research Laboratory, Utah State University, Logan, UT,
84322-8200, 2Department of Biochemistry and Microbiology, Faculty of
Food and Biochemical Technology, Institute of Chemical Technology, Technicka 3,
CZ-166 28 Prague 6, CZECH REPUBLIC, 3Department of Plant Tissue
Cultures, Institute of Organic Chemistry and Biochemistry, Academy of Sciences
of the Czech Republic, Flemingovo n. 2, CZ-166 10 Prague 6, CZECH REPUBLIC,
4Biotechnology, Utah State University, Logan, UT, 84322-4700,
5Biology, Utah State University, Logan, UT, 84322-5305, and
6Department of Plant Physiology and Botany, Gregor Mendel University
of Agriculture, Zemedelska 1, 61300 Brno, CZECH REPUBLIC

Phytoremediation or the use of plants to ameliorate sites contaminated with
inorganic and organic wastes is an increasingly interesting area of research.
Plants growing near mining sites or smelter operations or near
naturally-occurring metal-containing soils have developed rare characteristics
that allow these plants to either exclude metal from plant tissue or absorb
large amounts of metals into the plant biomass. Plants that accumulate zinc,
copper, or cadmium in levels exceeding 10,000, 1,000, or 100 mg metal/kg
biomass, respectively, in the above-the-ground portion of the plant are
considered to be hyperaccumulators. By growing these hyperaccumulators on
metal-contaminated sites, the metals can be transferred from the soil into plant
tissue, thus concentrating metals into a form that is easily disposed of. Many
of these naturally-occurring hyperaccumulators, however, produce very little
biomass and thus are not suitable for use in phytoremediation technologies.

Recent development in biotechnology and genetic engineering have found
certain proteins in animals, yeasts, and fungi called metallothioneins (MTs)
which bind a variety of metals very effectively. Through genetic engineering,
molecular coding techniques were used to design unique gene constructs encoding
proteins with high affinity for certain metals. These constructs are being used
to transform tobacco plants with a commercially-available plasmid. Preliminary
research has investigated the metal tolerance and accumulation of the bacteria
E. coli as a host for the MTs. Results indicated an increased tolerance
to metal rich environments by bacteria containing the MT protein. Transgenic
tobacco seeds germinated on media spiked with zinc also showed increased
tolerance to the zinc when compared to non-transgenic tobacco seedlings.

Accumulation of cadmium, copper, and zinc by transgenic and non-transgenic
tobacco plants in hydroponics is being investigated. Tobacco plants have played
important roles in genetic engineering techniques as they lend themselves well
to genetic research. In addition, the plants produce significant amounts of
biomass which enhances their usefulness in phytoremediation technologies.
Further optimization studies will be conducted to investigate the accumulation
of metals from soils contaminated with cadmium, copper, and zinc by transgenic
and non-transgenic tobacco plants.

Key words: phytoremediation, hyperaccumulator, tobacco, metallothionein.

Poster presentation.

43 • IDENTIFYING GROUND WATER THREATS FROM IMPROPERLY
ABANDONED BOREHOLES

R.F. Kubichek1, J.C. Cupal2, S. Choi, B. Qiu, J.D.
Burke, and M. Morris, Electrical Engineering Department, University of Wyoming,
Laramie, WY, 82071-3295, e-mail: [email-masked],
[email-masked]

Plugged and abandoned oil and gas wells represent a little understood threat
to fresh-water aquifers. Improperly plugged boreholes provide an easy path for
fluid communication between subsurface formations. In such cases, an aquifer can
become contaminated with oil, gas, or dissolved solids such as selenium and salt
from adjacent rock layers. Proper abandonment procedures dictate installation of
cement plugs within the borehole to seal off fresh-water aquifers and protect
water quality. Unfortunately, following these procedures is quite expensive, and
many wells may be closed illegally using a single cement plug at the surface.
Only a small percentage of wells are closed under the supervision of federal or
local inspectors, and it is currently impossible to estimate what fraction of
abandoned wells require mitigation. Environmental and law enforcement agencies
can verify the proper placement of downhole cement plugs only by re-drilling the
well-an expensive and risky operation.

This paper describes a research effort to develop acoustical methods for
sensing plug locations. The proposed technique uses sonic pulse propagation
along the casing or borehole wall, combined with computer modeling and advanced
signal processing techniques, to determine the depth of coherent cement plugs in
an abandoned well. Preliminary results using a full-scale horizontal borehole
mockup are presented, including hardware test setups, modeling and data
analysis, and signal processing results.

Key words: plug detection, well abandonment, aquifer.

Poster presentation.

44 • CONTAMINANTS MINERALIZATION USING ACTIVATED CARBON-AOPs
SYSTEM

P. Lo and A. Hong, Department of Civil and Environmental Engineering,
University of Utah, Salt Lake City, UT, 84112

Activated carbon adsorption is widely used in contaminants removal
application. Both granular activated carbon (GAC) and powered activated carbon
(PAC) are used for removal of a wide variety of organic compounds from
contaminated ground water, industrial waste streams, and biological effluents.
It is a developed technology that is able to remove soluble organic compounds
and toxic substances. Typical activated carbon contactors require the removal of
spent carbon, regeneration, and/or addition of new carbon. The procedure may be
cumbersome and less economical. This paper will focus on the regeneration of
spent activated carbon using Advanced Oxidation Processes (AOPs). We have
employed AOPs involving chemical oxidants, ozone (O3), and hydrogen
peroxide (H2O2) to mineralize contaminants that are
adsorbed and accumulated on the activated carbon surface. Results have shown
that AOPs are a viable technology for the regeneration of activated carbon. The
technology is capable of extending the service lifetime of activated carbon,
hence increasing the economic value.

Key words: activated carbon, adsorption, AOPs, regeneration.

Poster presentation.

45 • KINETICS AND MECHANISM OF DEGRADATION OF HAZARDOUS
CONTAMINANTS USING OZONE AND HYDROGEN PEROXIDE

V. Capps and A. Hong, Department of Civil and Environmental Engineering,
University of Utah, Salt Lake City, UT, 84112

Treatment of hazardous contaminants utilizing ozone in the presence of
hydrogen peroxide has shown great potential for complete destruction of
recalcitrant compounds. However, the kinetics and mechanisms of degradation are
often complex and involve a series of free radical reactions. In an attempt to
optimize the ozone/peroxide system for use in the remediation process, test
contaminants are used to model relevant system parameters, such as pH,
contaminant concentration, and ozone and peroxide dosage. This paper will focus
on the use of test contaminants to verify a proposed kinetic model for the
ozone/peroxide system.

Key words: AOPs, kinetics, mechanism, contaminant, remediation.

Poster presentation.

46 • METABOLISM OF TNT ASSOCIATED WITH ROOTS OF HIGHER
PLANTS

L.C. Davis and N.C. Chou, Department of Biochemistry, Kansas State
University, Manhattan, KS, 66506

Trinitrotoluene (TNT) is a common contaminant in ordnance facilities
throughout the central U.S. Former disposal practices led to accumulations of
relatively high concentrations of this low solubility compound. The
contamination is generally widely dispersed and in some locations it is leaching
toward ground water. Recent reports (c.f. van Beelen and Burris, 1995,
Environ Toxicol and Chem 14:2115-2123) have indicated that nitroreductase
enzymes found in sediments of streams or ponds may reduce TNT to different
aminodinitrotoluenes and/or further reduced materials. The same or similar
reductase activity has been reported to be associated with aquatic plants
(Schnoor et al., 1995, Environ Sci Technol 29:318A-323A).

We conducted a survey of several genera of higher plants growing
hydroponically to determine whether nitroreductase activity might be associated
with the roots of these plants. The main analytical tool has been HPLC to
monitor disappearance of TNT and appearance of metabolites. A Hamilton PRP-1
column was used with 65% acetonitrile, 1 mM KOH. Scanned spectra were obtained
for some of the eluted peaks but it proved difficult to reliably identify
compounds by their uV spectral characteristics.

Most plants that we tested showed relatively similar rates of TNT
disappearance when expressed on a root fresh weight basis. Monocots examined
included sorghum, maize, papyrus, and cattails. Dicots included soybean,
alfalfa, sunflower, pumpkin, tomato, amaranthus, poplar, and tamarix.

When intact plants were incubated in a solution of 50 mg/l TNT plus 1 mM
phosphate buffer pH 6.8, at a ratio of near 1 g root tissue per 50 ml solution,
there was nearly complete loss of TNT within 24 hours. Initially a more polar
metabolite, believed to be aminodinitrotoluene, appeared. At later times a still
more polar metabolite peak was observed, at the same time that the heights of
all peaks diminished. Activity was decreased several fold by separating roots
from the plant and even more by freezing roots overnight.

During the short exposure times studied here, a few days, plants were not
obviously injured when phosphate buffer was provided. Tamarix was treated
repeatedly with a lower concentration of TNT (10 mg/l) without apparent injury.
In contrast, a water plant, milfoil, was rapidly killed at this same
concentration and disintegrated within 2 days. An earlier study with yellow
nutsedge (Palazzo and Leggett, J Environ Qual 15:49-52) found severe
inhibition of plant growth at TNT concentrations as low as 5 mg/l, but in that
case the ratio of root to solution was very small, and the authors replenished
the TNT after 3 weeks. In that study high concentrations of metabolites were
found within the root systems (including rhizomes and tubers) of the plants
after 42 days. We did not examine plants for accumulation of metabolites,
because no isotopic tracers were used and the accumulation time was relatively
short. Disappearance of TNT and metabolites from solution suggests that there
was in fact uptake into the plants.

Key words: bioremediation, trinitrotoluene, water, plants.

Poster presentation.

47 • MEASURING CONTAMINANT FLUX THROUGH PLANTS BY FOURIER
TRANSFORM INFRARED (FT-IR) SPECTROMETRY

V.D. Makepeace1, L.C. Davis2, J. Dana3, K.
Selk2, K. Smith3, R.M. Hammaker1, W.G.
Fateley1, and L.E. Erickson3, Departments of
1Chemistry, 2Biochemistry, and 3Chemical
Engineering, Kansas State University, Manhattan, KS, 66506

Plant-based bioremediation depends on the ability of plants to survive in the
presence of contaminants, to metabolize or exclude contaminants, and to provide
nutrient supplementation to microbes that can accelerate contaminant
degradation. Plants facilitate transport of contaminants by drawing water from
soil. Rates of water use may commonly exceed 1 cm per day (100,000 l/ha/day)
during the summer. This water usage in turn could lead to intermedia transfer of
volatile contaminants and exposure of plants to high concentrations of the
contaminants that are relatively nonvolatile and that are also partially
excluded by the plant root system.

Fourier transform infrared spectrometry (FT-IR), with a long path length
extractive instrument (Gasmet, by Temet Instruments) allows detection of many
common volatile materials at levels below 1 ppm (v/v). We examined the movement
of common soluble, volatile gasoline constituents through two species of woody
plants, hybrid poplars (Populus deltoides x nigra) and salt-cedar
(Tamarix parviflora). Both species are rapidly growing, water
consumptive, and drought-resistant. In each case 1% deuterated water was used to
provide an FT-IR detectable marker for the rate of transpiration through the
plants. Contaminants were supplied to the root system in a closed flask with an
equilibrated headspace. The top portion of the plants was enclosed in a 78.5 l
closed chamber from which air was drawn by a pump through the FT-IR instrument
at about 1 l/min. Refrigerated coils condensed water, allowing accumulation of
contaminant above the relative water concentration in the chamber. The need to
supply CO2 (from room air) for photosynthesis limited the maximum
concentration ratio that could be achieved.

Contaminants tested included benzene, toluene, ethyl benzene,
meta-xylene, 1,2,4-trimethyl benzene, cyclohexene, n-pentane,
ethyl ether, n-propyl ether, and t-butyl methyl ether. Most
aliphatic hydrocarbon constituents of gasoline were not water soluble to
sufficiently high concentration for study. A wide range of octanol-water
partition coefficients is represented by the series chosen here, from about log
Kow 0.8 to 3.4. According to the work of Briggs et al.
(Pestic Sci 13:495-504) these Kow values span a range of
transpiration stream concentration factors (TSCF) from about 0.3 to 0.8, with
the highest TSCF for compounds like benzene and toluene.

Ethyl benzene, xylene, and trimethyl benzene (least polar) were often toxic
to the plants at the initial concentration of ~1 mM. Other compounds were
tolerated at levels up to 2 mM in the aqueous phase surrounding the root system.
The three least polar compounds, which also have unfavorable TSCF values, were
difficult to detect in the gas phase surrounding the plant tops. Other compounds
were detectable at levels related to water usage and TSCF. We conclude that
volatile contaminants can move through plants, much like nonvolatile pesticides
of varying polarity. Studies of chlorinated hydrocarbons will be reported
elsewhere.

Key words: gasoline, Fourier transform infrared spectrometry, bioremediation,
ground water, transpiration.

Poster presentation.

48 • EVALUATION OF TOXICITY OF TRICHLOROETHYLENE FOR
STERILE-GROWN PLANTS

S.B. Ryu1, L.C. Davis1, J. Dana1, K.
Selk1, and L.E. Erickson2, Departments of
1Biochemistry and 2Chemical Engineering, Kansas State
University, Manhattan, KS, 66506

Plants have the potential to remediate a number of toxic compounds but there
is very little literature on the ability of plants to tolerate high levels of
common solvents. If plants are to be used for clean-up of compounds such as
trichloroethylene (TCE), the first requirement is that they be able to survive
in its presence. Studies of the transport of a number of compounds through
plants indicate that they can tolerate exposure of their root systems to a 1 mM
aqueous concentration. Compounds that were tolerated for at least 24 hours by
one or more species included trichloroethylene, trichloroethane, chloroform,
dichloromethane, and carbon tetrachloride. These studies were done with
relatively large plants of alfalfa (Medicago sativa), hybrid poplars
(Populus deltiodes x nigra), and saltcedars (Tamarix parviflora).

Studies were done to measure the damage induced by exposure of entire plants
to comparable concentrations of a representative contaminant. Soybean seedlings
were exposed to levels of TCE up to 2 mM in the gas phase surrounding the entire
plant. Severe damage was evident at 0.5 mM as shown by electrolyte leakage.
Plants were killed at higher concentrations.

Tobacco plants, regenerated from callus, and growing aseptically on agar
medium, were tested with levels of TCE ranging up to 100 mM. No visual evidence
of damage was observed and the plants remained healthy for a week. There was no
significant decrease of TCE levels in the gas phase between two and seven days,
suggesting that the plants did not rapidly metabolize TCE. However, observable
metabolism is highly dependent on mass/volume ratios unless isotopic tracers are
used. With intact plants in sealed containers, depletion of CO2
becomes a problem unless there is a regulated source of CO2 or large
volume containers are used.

Key words: plants, trichloroethylene, toxicity, bioremediation.

Poster presentation.

49 • MOBILIZATION AND TRANSPORT OF DEPLETED URANIUM FROM
SURFACE SYSTEMS

P.N. Graham and C.L. Tiller, Environmental Engineering, Georgia Institute of
Technology, Atlanta, GA, 30332-0512

Depleted uranium (DU) is a by-product of uranium enrichment for nuclear power
generation and is used extensively in military applications. As a result of the
testing of DU penetrators at U.S. Army sites such as Yuma Proving Grounds and
Aberdeen Proving Grounds, DU can potentially be distributed in the environment
and contaminate surface systems. Since DU is a toxic heavy metal, having the
potential for affecting human health and ecosystems, there is a need to
understand and predict the transport and fate of DU in the environment. A model
combining chemical speciation and physical transport calculations was developed
to provide a tool for assessing the potential for long-range transport of DU
through runoff and surface waters. The mobilization of DU from a site of surface
contamination is initially controlled by the corrosive oxidation of the
elemental uranium. In oxygenated water, oxidation occurs rapidly and is unlikely
to limit transport, except perhaps in arid environments. In reduced waters,
however, initial mobilization of DU can be the rate-limiting step. In a stream
modeled under a variety of conditions of pH, redox potential, and concentrations
of dissolved inorganic carbon, the rate and extent of transport of DU was
largely determined by whether it existed primarily as insoluble uraninite
(UO2(s)) or as mobile uranyl hydroxides and uranyl carbonates. The
potential for transport of DU is also significantly affected by the availability
and characteristics of sorbent phases such as clay minerals, iron oxyhydroxides,
and organic matter. For example, a model of the potential for transport of DU
during infiltration suggests that the extent of transport can vary by as much as
an order of magnitude depending on soil characteristics.

Key words: depleted uranium, transport, surface water.

Poster presentation.

50 • RESEARCH, DEVELOPMENT, AND DEMONSTRATION (RD&D)
PERMIT PROCESS FOR THE TREATMENT OF RADIOACTIVE/HAZARDOUS WASTE

B.I. Krogfuss1, F.A. Walker2, and L.C.
Weers3, 1Kaiser-Hill, U.S. Department of Energy, P.O. Box
928, Golden, CO, 80402-0928, 2RMRS, U.S. DOE, P.O. Box 928, Golden,
CO, 80402-0928, and 3Colorado Department of Public Health and
Environment, HWMWD-SWIM-B2, 4300 Cherry Creek Drive South, Denver, CO,
80222-1530

Rocky Flats Environmental Technology Site (RFETS) obtained an RD&D permit
for microencapsulation of mixed waste. RD&D permits require slightly
different permitting strategy than obtaining a full RCRA Part B permit. This
paper outlines permitting strategies and streamlining strategies for RD&D
permits.

Key words: RD&D permit, RCRA, polymer microencapsulation, radioactive
waste, hazardous waste, nuclear waste storage, mixed waste, LDR treatment.

Poster presentation.

51 • EFFECTS OF FERTILIZATION RATES ON PHYTOREMEDIATION OF
PETROLEUM-CONTAMINATED SOILS

S.L. Lewis1, M.K. Banks1, and A.P. Schwab2,
Departments of 1Civil Engineering and 2Agronomy, Kansas
State University, Manhattan, KS, 66506

In order to determine the optimal nutrient levels for maximum petroleum
degradation using phytoremediation, four different fertilization rates will be
tested in a greenhouse experiment using a C4 plant, bermuda grass (Cynodon
dactylon), a C3 plant, tall fescue (Festuca arundinacea), and an
unplanted control. Fertilization rates will be based on the soil C:N ratio for
plant requirements as well as microbial needs. This study will indicate the
importance of nutrient availability for maximizing phytoremediation rates of
petroleum-contaminated soils.

Key words: phytoremediation, nutrients requirements, fertilization rates.

Poster presentation.

52 • AN ASSESSMENT OF MICROBIAL CHANGES DURING
PHYTOREMEDIATION

S.D. Pekarek, J. Keller, M.K. Banks, and A.P. Schwab, Kansas State
University, Manhattan, KS, 66506

Phytoremediation is the use of plants to enhance bioremediation of polluted
soil. Microbial degradation is an important dissipation mechanism during this
process. Data from a greenhouse study designed to evaluate changes in microbial
numbers and communities will be presented. Results from this study will help
assess the microbial contribution to phytoremediation of petroleum-contaminated
soil.

Key words: phytoremediation, microorganisms, petroleum contamination, soil,
degradation.

Poster presentation.

53 • DETERMINATION OF TOTAL PETROLEUM HYDROCARBONS IN
CONTAMINATED SOIL

J. Su and A.P. Schwab, Department of Agronomy, Kansas State University,
Manhattan, KS, 66506

Soxhlet extraction is the standard method in the determination of total
petroleum hydrocarbons (TPH) in soil, and the soil is kept at field moisture to
avoid losses of volatile constituents. However, the soil remains static in the
soxhlet extractor which limits the exposure of soil surfaces to the solvent.
Subsampling errors increase in moist soils because they are difficult to
homogenize, and hydrophobic solvents lose efficiency in moist soils even when
drying agents such as sodium sulfate are employed. We compared the efficiency of
TPH extraction using shaking versus soxhlet, field moist versus dry soil, and
three different solvents. Extraction of moist soils by either shaking or soxhlet
yield slightly lower TPH concentrations and much higher variability compared to
extraction of dry soil. Soxhlet and shaking resulted in the same soil TPH
concentrations if the shaking involved three or more successive extractions with
clean solvent. Shaking moist soils with hydrophilic solvents (e.g., acetone) was
more efficient than hydrophobic solvents (e.g., methylene chloride) for the
first extraction, but the TPH removed after three extractions was independent of
solvent. We conclude that shaking dry soils yields the same concentrations as
soxhlet extraction but many more soils can be processed using shaking.

Key words: total petroleum hydrocarbons (TPH), soil, shaking soxhlet.

Poster presentation.

54 • EFFECT OF PLANT EXUDATES ON THE BIOREMEDIATION OF
SYNTHETIC DIESEL FUEL

K. Rathbone, A.P. Schwab, and M.K. Banks, Kansas State University, Manhattan,
KS, 66506

Increased root surface area and plant exudates output are implied to promote
microbial activity in the rhizosphere. Different species of sorghum are being
studied based on their exudate production to increase bioremediation of
synthetic diesel fuel. Four types of sorghum with differing amounts of exudate
release were planted in a sandy loam soil contaminated with 0.25% synthetic
diesel fuel. Three time periods were used for take down of samples; 5 leaf
stage, flowering, and maturation. Microbial activity, plant uptake, and the soil
degradation of diesel fuel will be presented and discussed. Results from this
study will help assess important root characteristics for plants during
phytoremediation.

Key words: bioremediation, exudates, rhizosphere, diesel fuel, plants.

Poster presentation.

55 • THE IMPACT OF VEGETATION ON HEAVY METAL MOVEMENT

D. Zhu1, A.P. Schwab1, M.K. Banks2, and E.X.
Wang2, 1Department of Agronomy, and 2Department
of Civil Engineering, Kansas State University, Manhattan, KS, 66502

The establishment of vegetation in mining areas is a primary method to
minimize metal contamination through wind erosion, runoff, and infiltration.
Plants may decrease heavy metal leaching by plant uptake, stimulating microbial
immobilization of metals in the rhizosphere, and decreasing water flow. However,
organic compounds, especially organic acids exuded by plants and microbes, may
increase heavy metal solubility. Also, channels created by the plant root system
may greatly increase metal movement through preferential flow. We evaluated the
effects of a warm-season grass and cool-season grass on the leaching of Zn, Cd,
and Pb from mine tailings. The leaching experiment was conducted under
unsaturated conditions using multilayered columns. Metals leached were monitored
for 10 months, and total mass of leached metal was calculated. The subsoil in
the columns will be extracted and the heavy metals in the plant biomass will be
analyzed after the leaching experiment is concluded. These lab results will
provide us with important information concerning the use of vegetation for
mining site remediation.

Key words: heavy metal, phytoremediation, leaching, column, ground water.

Poster presentation.

56 • THE EFFECT OF FLUCTUATING WATER LEVELS ON
BIODEGRADATION OF NAPLS IN SOIL

L. Schuckman, M.K. Banks, and L.N. Reddi, Civil Engineering Department,
Kansas State University, Manhattan, KS, 66506

Multi-layer soil columns were constructed and contaminated with NAPLs to
determine optimal bioremediation strategies for the remediation of discontinuous
contaminated soil. A detailed examination of these columns will yield
information about the soil physical and chemical properties, zone of
accumulation, microbial characteristics, flow of nutrients, and biodegradation
of target compounds.

Key words: nonaqueous phase liquids, bioremediation, ground water, soil.

Poster presentation.

57 • BIODEGRADATION KINETICS OF CARBON TETRACHLORIDE,
PERCHLOROETHYLENE, AND 1,1,1-TRICHLOROETHANE WHEN PRESENT IN MIXTURES

D.T. Adamson and G.F. Parkin, 125 Engineering Research Facility, The
University of Iowa, Iowa City, IA, 52242

The effect of mixtures of chlorinated aliphatics on biotransformation of the
individual compound is being investigated using methanogenic enrichment
cultures. Carbon tetrachloride (CT), perchloroethylene (PCE), and
1,1,1-trichloroethane (TCA) are known to be degraded anaerobically through
reductive dechlorination. Cultures are fed acetate as a carbon and energy source
and then exposed to various combinations and concentrations of these compounds.
Disappearance of parent compounds and appearance of transformation products is
measured using gas chromatography. Biodegradation kinetics are determined using
pseudo-first-order rate expression ("biomass-corrected"). Rate constants for the
individual compounds when present alone and in mixtures are compared in order to
assess the relative effects of each. Methane production and acetate utilization
are also measured to determine the impact of exposure to mixtures on
methanogenesis. Initial results indicate that the presence of a mixture
significantly reduces the rate of degradation of the individual compound. With
unacclimated cultures, CT is degraded most rapidly, followed by TCA and PCE. The
presence of the mixture reduces acetate utilization and methane production
significantly when compared with exposure to an individual compound. Attempts
are also being made to develop acclimated enrichment cultures by initially
adding low concentrations of the compounds and gradually increasing the
concentration over time. Rate constants obtained from the acclimated culture
will then be compared to those for the unacclimated culture. These results
should be helpful in developing remediation strategies for sites contaminated
with mixtures of chlorinated compounds.

Key words: bioremediation, mixtures, chlorinated aliphatics.

Poster presentation.

58 • SEQUENTIAL TRANSFORMATION OF CARBON TETRACHLORIDE,
PERCHLOROETHYLENE, AND 1,1,1-TRICHLOROETHANE USING METHANOGENIC AND
METHANOTROPHIC CONDITIONS

S.J. Christ and G.F. Parkin, 125 Engineering Research Facility The University
of Iowa, Iowa City, IA, 52242

Sequential, methanogenic-methanotrophic biofilm reactors are being employed
to study the biodegradation of carbon tetrachloride (CT), perchloroethylene
(PCE), and 1,1,1-trichloroethane (TCA). Two sequential, glass-bead reactor
systems were seeded with an acetate enrichment culture (first column) and a
methanotrophic enrichment culture (second) column. One system is fed PCE while
the other is fed a mixture of CT, PCE, and TCA. A third sequential reactor
system consists of an anaerobic column filled with steel wool and seeded with an
acetate enrichment culture, followed by a glass-bead column seeded with a
methanotrophic enrichment culture. This column is fed a mixture of CT, PCE, and
TCE. It is hypothesized that the methanogens in the first reactor will transform
(by reductive dechlorination) the highly chlorinated CT, PCE, and TCA into
lesser chlorinated compounds such as dichIoromethane, dichloroethylene, and
dichloroethane, which will in turn be mineralized by the methanotrophs in the
second column. Acetate will be fed to the glass-bead columns while the
H2 produced from the anaerobic corrosion of the Fe0 in the
steel-wool column will serve as the energy source for the methanogens. Influent
concentrations of these compounds will be gradually increased over time to
investigate the capacity of these systems to degrade, and hopefully mineralize,
the target compounds and their expected metabolites (e.g., chloroform and
dichloromethane from CT; trichloroethylene from PCE; 1,1-dichloroethane from
TCE; etc.). Initial concentration is 1 mM for each compound.

Key words: sequential bioremediation, methanogens, methanotrophs, chlorinated
aliphatics.

Poster presentation.

59 • NICKEL UPTAKE BY THE HYPERACCUMULATOR STREPTHANTHUS
POLYGALOIDES GROWN ON SERPENTINE AND CALCAREOUS SOILS

J.L. Cramer and P.R. Grossl, Department of Plants, Soils, and Biometeorology,
Utah State University, Logan, UT, 84322-4820

The need to discover less costly means of remediating metal-contaminated land
has led to an ever-growing interest in phytoremediation. We are growing the
nickel hyperaccumulator Strepthanthus polygaloides in contaminated soils
to determine the amount of nickel accumulated in the roots, shoots, and leaves.
The two soils used in this study are a serpentine soil from California and a
calcareous soil from Utah that was spiked with 3,000 ppm nickel. No nickel was
added to the serpentine soil, which has an inherent total nickel concentration
of approximately 3,000 ppm. Based on previous studies, it is predicted that
Strepthanthus polygaloides should accumulate nickel to a concentration of
9,000 ppm in its leaves. This is nine times the level required for recognition
as a hyperaccumulator. To the soil we will add either nitrate
(NO3--N) or ammonia (NH4+-N) to
examine if these amendments will enhance nickel accumulation beyond predicted
values. With this information new techniques of remediating metal-contaminated
land using Strepthanthus polygaloides can be developed.

Key words: strepthanthus polygaloides, hyperaccumulator, nickel.

Poster presentation.

60 • MINERALIZATION OF PENTACHLOROPHENOL IN SOIL BY
WHITE-ROT FUNGI IN THE PRESENCE OF SURFACTANTS

R.A. Doughten1, W.P. Inskeep1, and C.G.
Johnston2, 1Department of Plant, Soil, and Environmental
Sciences, Montana State University, Bozeman, MT, 59717, and 2Mycotech
Corporation, Butte, MT, 59702

Pentachlorophenol is a common and persistent contaminant of soils at
wood-preserving facilities. White-rot fungi have been identified as possessing
enzyme systems capable of degrading PCP; however, degradation may be limited by
contaminant sorption to soils. Surfactants can be used to minimize this
limitation by increasing the bioavailability of sorbed hydrophobic molecules in
soils. A non-Phanerochaete white-rot fungi, identified as Mycotech strain
"F600," was evaluated for its ability to degrade 14C-PCP applied to a
sterile agricultural soil amended with five surfactants (lignosulfonic acid,
sodium salt; lignosulfonic acid, sodium salt, acetate;
hydroxypropyl-b-cyclodextrin; Tween 80; Triton X-100). Each surfactant was
applied to the contaminated soil at 25 mg g-1 soil, concentrations
similar to soil organic matter content. Mineralization was measured as the
amount of 14CO2 recovered from soil columns flushed with
air; fungal activity was estimated from respiration rates measured by titrating
trap solutions with standardized acid. In four weeks, 36% of the applied PCP was
mineralized in the Tween 80 treatment whereas 23% of the applied PCP was
mineralized in the non-surfactant control. In addition, the initial
mineralization rate in the presence of Tween 80 was significantly higher than
other treatments. The other four surfactants decreased PCP mineralization or
were similar to the control. Fungal activity (total respiration) over the same
time period was not significantly different among surfactant treatments. The use
of surfactants, such as Tween 80, in combination with white-rot fungi may
represent a strategy for the bioremediation of residual PCP in contaminated
soils.

Key words: surfactants, degradation, white-rot fungi, pentachlorophenol.

Poster presentation.

61 • RELATIONSHIP BETWEEN BIOLOGICAL AND CHEMICAL GROUND
WATER DATA AT A URANIUM MILL TAILINGS SITE

H.A. Noskin1, K. Choudhury2, and L.L.
Barton2, 1Los Alamos National Laboratory, Los Alamos NM,
87545, and 2Department of Biology, University of New Mexico,
Albuquerque, NM, 87131-1091

Analysis of chemical and bacteriological data obtained from ground water
studies from the Gunnison, Colorado, uranium mill tailings site was performed in
three parts: (i) analysis of bacteriological data from pristine wells and from
wells in the plume region; (ii) analysis of chemical or environmental data from
these well sites; and (iii) modeling of the ground water data with the
bacteriological data. Correlations and significance levels were determined using
SAS analysis. Of the 66 environmental variables for these wells, 24 were useful
to provide differences between the wells. The relationships among all the
variables were clustered as groups, and pair comparisons of the variables for
positive and negative correlations were performed. Information will be presented
to indicate the method most useful to determine correlations between
environmental and bacterial characterization of ground water.

Key words: ground water quality, uranium sites, environmental correlations.

Poster presentation.

62 • APPLICATION OF BIOSENSORS BASED ON NATIVE FLUORESCENCE

D.W. Morrison1, L.L. Barton1, R.F.
Cifuentes2, and W.C. Lindemann2, 1Department of
Biology, University of New Mexico, Albuquerque, NM, 87131-1091, and
2Department of Agronomy, New Mexico State University, Las Cruces, NM,
88003-8001

The monitoring of bacteria in the environment is often required to assess
specific bioremediation processes. An approach that we have employed is to use
fluorescence to detect molecules that serve as signatures for specific bacteria
and to employ dyes for staining of bacteria present. The data presented here
indicate that fluorescence can be used in the quantitation of methane-producing
bacteria and sulfate-reducing bacteria by detecting specific molecules for each
of these physiological types of bacteria. Additionally, chelator molecules
specific for metals that are produced by various types of bacteria can also be
measured by fluorescence. This would be important to predict in situ
activities of these bacteria. Finally, selective strains discriminate between
live and dead bacteria through the type of fluorescence produced. Each of these
molecules has a specific wavelength for excitation and emission, thereby
providing a basis for identifying bacteria or bacterial activities in the
environment.

Key words: fluorescence, biosensor, bacterial identification.

Poster presentation.

63 • STRATIFICATION OF SOIL CHEMICAL PROPERTIES IN
REVEGETATED CHAT

G.M. Pierzynski1, J. Xie1, and M.R.
Norland2, 1Department of Agronomy, Kansas State
University, Manhattan, KS, 66506, and 2U.S. Bureau of Mines, 5629
Minnehaha Ave. South, Minneapolis, MN, 55417

Vegetative remediation of large areas of zinc/lead mine spoils is an
increasingly popular option given the economic restraints that are often
associated with remediation activities. Little is known about the long-term
effects of vegetation on the stratification of soil chemical properties in
revegetated chat. A field study was initiated in 1990 comparing various sources
and rates of organic wastes as soil amendments for revegetating chat. Zinc
phytotoxicity and poor soil physical properties were the most limiting factors
in establishing plant growth. The use of cattle manure at 90 Mg/ha was the most
successful amendment with no growth occurring on unamended chat. Soil samples
were collected from 0 to 7.5 cm by 2.5 cm increments in 1996 from plots
receiving 90 Mg/ha cattle manure and from the control plots. Total metal
analysis of these samples indicated that Zn and Cd concentrations were
significantly lower at 0-2.5 cm for vegetated plots compared to unvegetated
plots with the opposite being true for Mn. At this same depth there were no
significant differences in metal concentrations for Cr, Cu, Fe, Ni, and Pb.
Generally, vegetation had no effect on metal concentrations below 2.5 cm with
the exception of Pb which was significantly higher with vegetation compared to
no vegetation at 2.5-5.0 and 5.0-7.5 cm. Additional samples will be collected to
a great depth and analyzed for organic C, pH, and total and bioavailable metal
concentrations

Key words: zinc, lead, vegetation, remediation, mining.

Poster presentation.

64 • PHOTOCATALYTIC REDUCTIVE DEHALOGENATION OF
TRICHLOROETHYLENE AND CARBON TETRACHLORIDE USING OPTICAL FIBERS COATED WITH
TiO2-CoTSP

S.B. Gogosha1, R.G. Arnold1, and E.A.
Betterton2, 1Department of Chemical and Environmental
Engineering, University of Arizona, Tucson, AZ, 85721, and
2Department of Atmospheric Sciences, University of Arizona, Tucson,
AZ, 85721

Heterogeneous photocatalysis on the surface of metal-oxide semiconductors
such as TiO2 has been widely used for the decomposition of
chlorinated organics in water. The hybrid semiconductor-macrocycle catalyst
TiO2-cobalt tetrasulfophthalocyanine (TiO2-CoTSP) promotes
the reductive dehalogenation of bromoform (CHBr3) under anaerobic
conditions. In previous work, coated TiO2 particles were suspended in
the reactors. The nature of these suspensions prevented light from penetrating
into the reaction mixture and decreased the effectiveness of the system. Also,
removal of the particles from the water was difficult, a liability for potential
field applications. Attachment of TiO2-CoTSP to the surface of an
optical fiber is proposed as a solution to these problems. This research
explores the feasibility of using a coated optical fiber to provide both the
light source to induce the photocatalytic properties of the
TiO2-CoTSP and a surface to support the photocatalyst. Different
techniques for coating the fiber with TiO2 and attaching CoTSP were
studied. Reductive dehalogenation of TCE and carbon tetrachloride was carried
out using both the modified and unmodified fibers. The quantum efficiencies of
the two systems were compared to each other and to published data.

Key words: reductive dehalogenation, remediation, aquifer, optical fiber,
titanium dioxide.

Poster presentation.

65 • STRATEGIES FOR CONDITIONING OF SPENT RADIATION SOURCES
IN CUBA

J.C. Benitez, N. Garcia, M. Salgado, and L. Jova, Center for Radiation
Protection and Hygiene, 14 No. 308, Miramrar, P.O. Box 6195, Ciudad Habana, CUBA

Responsibility for the development of a national strategy for the management
of radioactive wastes in Cuba lies in the Center for Radiation Protection and
Hygiene. The current research program includes (1) improvement of radioactive
waste management in Cuba, (2) remodeling of the Cuban RadWaste Treatment Plant,
and (3) development and implementation of adequate methods for conditioning
spent radiation sources.

This paper describes the main considerations and facts taken into account for
the design and implementation of a set of procedures with all technical,
administrative, protective, and practical details for conditioning spent
radiation sources in Cuba.

Key words: radioactive waste management, spent radiation sources,
conditioning.

Poster presentation.

66 • THERMAL TREATMENT OF INDUSTRIAL-PRODUCED ACIDIC METAL
CHLORIDE HAZARDOUS WASTE

D. Knappe, Colorado Department of Public Health and Environment, Hazardous
Materials and Waste Management Division, 4300 Cherry Creek Drive South, Denver,
CO, 80222-1530

A State RCRA Research, Development, and Demonstration (RD&D) permit was
prepared for a research facility to the mining, mineral, and chemical
industries. The permit specified operating conditions for the thermal treatment
of acidic metal chloride waste. The acidic metal chloride waste is produced
industrially and is characterized as a hazardous waste under the Colorado
Hazardous Waste Regulations. The specific reaction occurring in the thermal
reactor involves the pyrohydrolysis of hazardous waste. The pyrohydrolysis
reaction utilizes heat, water, and a low amount of oxygen to cause a chemical
and physical separation in the waste. Expected byproducts of the reaction
include a nonhazardous byproduct and hydrochloric acid. If successful, the
pilot-scale plant will be built full-scale at industrial facilities handling
acidic metal chloride waste so that the hydrochloric acid can be recycled back
into the industrial process. The effectiveness of the thermal treatment system,
including the emission control design, and process controls will be evaluated
under the conditions and requirements of the State RCRA RD&D permit.

Key words: thermal treatment, chemical and material processing, hazardous
waste, RD&D permit, waste minimization.

Poster presentation.

67 • DNA BIOSENSOR FOR MONITORING HYDRAZINE COMPOUNDS

J. Wang, X. Cai, G. Rivas, and M. Flair, Department of Chemistry and
Biochemistry, New Mexico State University, Las Cruces, NM, 88003

Nucleic acids offer the environmental chemist a powerful tool in the
recognition and monitoring of many important pollutants. This poster will report
on a new DNA biosensor for the detection of hydrazine compounds. The sensor
relies on monitoring changes in the intrinsic response of the surface-confined
DNA resulting from its interaction with hydrazine compounds, and requires no
label or indicator. Short reaction times are sufficient for monitoring ppb
levels of different hydrazines.

This work was supported by the U.S. DOE through the WERC program.

Key words: hydrazines, DNA, sensor.

Poster presentation.

68 • ASSURING QUALITY MODEL USAGE, EXPERIMENTAL VALIDATION,
AND EXTRAPOLATION TO FIELD SITES

J.C. Tracy and V.R. Schaefer, Northern Great Plains Water Resources Research
Center, South Dakota State University, Brookings, SD, 57007

The effective use of a model for aiding in the design of a soil-water
remediation system requires an understanding of the reliability and limits of
the modeling approach. To assure the quality of modeling predictions requires
that the significant modeling processes are validated using the results of
highly-controlled experiments. However, the actual model use is typically in a
field setting with a limited amount of site characterization data available for
model calibration. A discussion of the procedures that should be followed for
validation of modeling processes and the usage of the validated model in a field
setting is presented. Methods for assessing the reliability of the modeling
approach and the uncertainty of applying the model in a field setting are also
addressed.

Key words: quality assurance, model validation, model usage.

Poster presentation.

69 • EXPERIMENTAL VERIFICATION OF REVISED FIRAC

P.R. Smith, E. Hensel, I. Leslie, and C. Ricketts, Mechanical Engineering
Department, New Mexico State University, Las Cruces, NM, 88003

The objective of this project was to carry out experimental studies of fires
within the ventilation system of a model nuclear facility in order to validate
the gas dynamic module and the heat transfer module of the FIRAC fire simulation
code developed by Los Alamos National Laboratory. The version of FIRAC to be
verified was one which successfully ran on CRAY computers, but revised to
operate on personal computers. The experiments necessary to evaluate the various
modules of the code were accomplished in the Large Scale Flow Facility at New
Mexico State University. This facility is a large-scale model which contains all
the elements, such as blowers, dampers, and High Efficiency Particulate Air
(HEPA) filters that are found in typical ventilation systems of nuclear
facilities. Several experiments were performed and the initial conditions were
input into FIRAC in order to check the simulated results against the
experimental results. The comparison of results indicated that the code predicts
the general behavior of the gas dynamic and heat transfer occurring within the
experimental ventilation during a fire fairly well. In addition to the
experiments performed at New Mexico State University, the code is also being
used to simulate a fire within a German nuclear reactor building. This
experiment was carried out by the personnel of Kernforschungszentrum of
Karlsruhe, Germany, at a decommissioned reactor building located in Karlstein,
Germany. The simulated results agree closely with the actual results.

Key words: FIRAC, nuclear, ventilation, fires, gas dynamic module.

Poster presentation.

70 • MODELING OF HEAVY METAL TRANSPORT AND SOIL EROSION IN
SURFACE RUNOFF

S.R. Ramireddygari1, R.S. Govindaraju1, and L.E.
Erickson2, 1Department of Civil Engineering and
2Department of Chemical Engineering Kansas State University,
Manhattan, KS, 66506

A physically-based model was developed for rainfall, runoff, erosion, and
solute transport processes on land surfaces under time-varying rainfall events.
Kinematic wave approximation was used to describe the overland flow dynamics.
Erosion equation was represented as a first-order reaction with the reaction
rate being represented by soil erodibility. The solute transport equations were
based on a convective-dispersive model that incorporates rate-limited mass
transfer through a laminar boundary layer at the soil surface/runoff water
interface. The model has been validated using the data available in literature.
Results for the erosion and solute transport processes were validated
separately. Experiments are planned for complete model validation.

Key words: modeling, heavy metal transport, soil erosion, overland flow.

Poster presentation.

71 • GAS-DRIVEN HYDROFRACTURE AT WIPP

W. Gerstle, Department of Civil Engineering, University of New Mexico,
Albuquerque, NM, 87131

This presentation reports on continuing research in the simulation of
gas-driven hydrofracture at the Waste Isolation Pilot Plant (WIPP). The
simulations employ analytical, computer, and physical models. Several advances
have been made in our understanding of the hypothesized formation of a
horizontal, circular hydrofracture several kilometers in radius. The fracture is
hypothesized to develop in an anhydrite layer. The hypothesized hydrofracture
could form in response to waste gases generated as brine comes into contact with
the waste. The possibility is investigated that after growing horizontally
within the anhydrite layer, the crack could break out of this layer and
propagate upward into the halite at an inclined angle of around 45º above
horizontal. This scenario is studied using analytical methods and a finite
element program capable of simulating linear elastic cracks. Results of physical
models also will be presented.

Key words: Waste Isolation Pilot Plant, hydrofracture, nuclear waste
management.

Poster presentation.

72 • FAST NEUTRON THERMALIZATION AND CAPTURE GAMMA-RAY
GENERATION IN SOILS

R.E. Faw, S.L. Shue, and J.K. Shultis, Nuclear Engineering Department, Kansas
State University, Manhattan, KS, 66506-2503

This is a report of progress on an investigation of the feasibility of using
prompt-neutron, capture gamma-ray, neutron activation analysis (PGNAA) to
determine the vertical concentration profiles of contaminants in soil. The
report, in particular, deals with the phase of the investigation pertaining to
neutron transport and thermalization in soil, the capture of neutrons in
contaminants such as heavy metals, and the transport of resulting gamma rays to
radiation measurement systems above the soil. A second phase of the research
deals with the inference of contaminant concentrations from measured gamma-ray
energy spectra.

Soil characteristics most affecting neutron transport and thermalization are
porosity and free-water content. Nominal characteristics, representative of many
soils, were found to be a porosity of 50% and a value of 0.2 for the ratio of
the free water mass in the soil to the mineral mass, resulting in an in
situ density of 1.61 g/cm3. Soil extremes were characterized by a
dry porous soil of density 1.18 g/cm3 and a wet dense soil of density
2.09 g/cm3.

Most neutron capture takes place after the neutron has slowed to conditions
of thermal equilibrium in the soil. It was found to be possible to determine
effective neutron capture cross sections, so that only the spatial variation of
the thermal-neutron flux density need be determined for different irradiation
geometries and soil conditions. The product of the flux density and the capture
cross section determines the capture gamma ray production rate per unit soil
volume per unit contaminant concentration. This results in very great savings in
data storage and manipulation requirements for those making use of PGNAA
technology. Using both Monte Carlo and discrete ordinates methods, such profiles
have been calculated and are illustrated. Methods were developed for computing
capture gamma-ray transport in the soil and representative energy spectra are
illustrated for selected contaminants and concentration profiles.

New applications of PGNAA technology are addressed in the report. Special
attention is given to extensions permitting the imaging of three-dimensional
artifacts buried in the soil. Two-dimensional images of buried drums of
hazardous waste, generated using Monte Carlo radiation transport calculations,
are presented in the report and methods for three-dimensional imaging are
discussed.

Key words: soil, contaminant, neutron capture gamma-ray.

Poster presentation.

73 • INTERPRETATION OF NEUTRON-CAPTURE GAMMA-RAY DATA TO
DETERMINE SOIL CONTAMINANT PROFILES

J.K. Shultis, F.A. Khan, and R.E. Faw, Department of Nuclear Engineering,
Kansas State University, Manhattan, KS, 66506-2503

Neutron irradiation of soil and measurement of the subsequent capture gamma
photons at the soil surface is a potentially powerful method for in situ
determination of vertical concentration profiles of many elemental contaminants.
For a particular contaminant, the intensity ci of the capture
photon with the i-th energy, i = 1,...N, at a point
detector located at or above the soil surface is given by an equation where
u(x) is the concentration of the contaminant at depth x and
Ki(x) is a known kernel appropriate to the neutron source and
detector used. The inversion of this Fredholm integral equation for u(x)
is notoriously difficult especially since the number N of measurable
capture photons with different energies is usually small, typically 3 to 10.

The capabilities and limitations of two different inversion techniques are
presented for the soil contamination problem. The first inversion method, linear
regularization (LR), approximates the integral equations by a set of
(underdetermined) algebraic equations of the form of an equation where
uj is the unknown contaminant concentration at M (>
N) discrete soil depths. Several methods for calculating the matrix
elements Rij from the kernels Ki(x) are
presented. The solution of these algebraic equations can then be obtained by
imposing additional constraints such as a variety of smoothness conditions.

The second inversion method, the Backus-Gilbert (BG) technique, seeks a
continuous solution û(x) of Eq. (1) that maximizes the resolution of
changes in u(x) subject to a numerical stability constraint. This method
has the advantage of explicitly depending directly on the measurement errors of
the ci, and although computationally more expensive than the
LR method, produces estimates of u(x) that are always non-negative.

Results of applying these two inversion methods and their variants to
benchmark test cases are presented. In particular, the sensitivities of the
inversion methods to measurement errors, the number and energies of the capture
gamma photons, detector geometry, concentration profile shapes, soil
composition, and model approximations are discussed.

Key words: neutron capture, soil data inversion.

Poster presentation.

74 • METALS SOIL POLLUTION AND VEGETATIVE REMEDIATION USING
POPLAR TREES AT TWO HEAVY METAL-CONTAMINATED SITES

W. Hse1, C. Just2, and J.L. Schnoor3, Rooms
1125, 2120, and 3116, Engineering Research
Facility, The University of Iowa, Iowa City, IA, 52242

Heavy metal-contaminated soils with arsenic (As), cadmium (Cd), lead (Pb),
and zinc (Zn) from two different Superfund sites at Dearing, Kansas, and
Whitewood, South Dakota, were monitored and compared. Poplar trees were planted
at both sites to stabilize soils and limit vertical migration of leachate to the
ground water. The southeast Kansas site, an abandoned smelter, has one of the
largest concentrations of lead and zinc in the soil that has ever been reported
for a hazardous waste site. Whitewood Creek site is the result of many years of
mine tailings processing and contains appreciable arsenic, up to 8,000 mg/kg in
hot spots.

The suitability of deep-planted hybrid poplar trees as a vegetative
remediation strategy for both heavy metal-contaminated sites has been
investigated and compared. An additional objective was to investigate the
influence of poplar cultivar and soil amendments on poplar tree survival and
growth.

This study has resulted in 1) a practical case study of vegetative
remediation at two extremely contaminated sites, 2) a comparison of heavy metals
uptake by vegetation for testing models of biogeochemistry, and 3) a surface
coordination chemical model that relates soil chemistry to biouptake.

Key words: mine waste remediation, vegetative remediation, poplar trees in
metals soil, soil chemistry.

Poster presentation.

75 • CLEAN-UP PROCEDURES FOR WASTE WATERS WHICH FLOW FROM
REFINERIES AND OTHER CHEMICAL COMPANIES

V. Calamaz and G. Calamaz, Romanian Waters Authority, Str. serg Gh. Mateescu
nr. 10, bloc 6, ap. 25, 2000 PLOIESTI Jud. PRAHOVA, ROMANIA

Romanian Water Authority-Ploiesti administrates the confined in the Prahova
District. These waters are over 300 km. The main rivers are Prahova and
Teleajen.

Prahova Country is well known as a beautiful tourist area, which contains all
the relief forms: mountains, hills, and plains. This district is recognized also
as an important industrial zone, represented by chemical and petrochemical
industry.

Besides a lot of advantages, this industry still has many bad effects like
water pollution. I work in the field of water quality and I am responsible for
this.

The Prahova and Teleajen rivers were known until a short time ago to have a
very high pollution concentration, especially with petroleum products and ash of
iron, coming from the great refineries and the chemical combinate.

These rivers are different now. And this is possible because of my ideas,
which are practiced on these channels with flowing waste water from the big
polluting companies.

The recovery of these petroleum products is done with the installations
designed by me.

The leaks are confined between 80-120 mg/l. Fixing in seria (after one) of
these installations, the petroleum products concentration became 2-4 mg/l. From
the chemical combinate, which are made of chemical products, the iron ash
confined in the waste water which is spilled, is confined between 1,200-1,600
mg/l. Using this recovery device, the final concentration is 30-60 mg/l. We used
this opportunity to aerate the water.

If everyone thinks with more responsibility of the people around him, we will
be a thousand times better off and more beautiful.

A motion picture with all these discoveries will be presented.

Key words: surface water clean up.

Poster presentation.

76 • EFFECTS OF PRESSURE VARIATION ON TRANSPORT OF VOLATILE
NONAQUEOUS PHASE WASTE CHEMICAL VAPOR IN HETEROGENEOUS FORMATIONS

E.M. Johnson1, T.H. Illangasekare1, N.D.
Rosenberg2, and L.H. Auer2, 1Department of
Civil Engineering, University of Colorado at Boulder, Boulder, CO, 80309, and
2Los Alamos National Laboratory, Los Alamos, NM

Understanding the transport of volatile organic chemicals in the vapor phase
in unsaturated soils is of basic importance in the development and
implementation of a number of remediation technologies such as passive vapor
extraction, enhanced vapor recovery, soil vapor extraction, aeration, and
big-venting. In these schemes, the pressure gradients in the gaseous phases are
used to move the vapor through the soil. External pressure (or vacuum) is
applied to create the driving gradients. In some vadose zone contamination
situations the cyclic variations of atmospheric pressure (barometric pumping)
that is enhanced through the use of boreholes or found naturally have been found
to mobilize and transmit the vapor phase to the ground surface. It is our
hypothesis that the soil heterogeneities play a significant role in the way
these pressures are transmitted and how the vapor phase gets mobilized. Existing
literature on the subject suggests that very little is known on the effects of
heterogeneities on contaminated gas flow through the vadose zone.

The objective of the research presented in this paper is to understand and
quantify the mobilization and movement of volatile organics in the heterogeneous
vadose zone as a result of barometric pumping. An experimental facility
consisting of a stainless steel column fitted with sampling ports to extract air
samples was developed. A pool of test chemical (TCA) was placed in the bottom of
the column and small cyclic pressure fluctuations were applied at the soil
surface at the top of the column in order to mimic the barometric pressure
changes. Extracted air samples were tested using a GC/FID to determine the
dynamic variation of vapor concentrations along the column. Experiments were
conducted with different heterogeneous packing configurations. The experimental
results are used to parameterize the hydrodynamic dispersion and effects of
cyclic pumping on VOCs in the vadose zone. The experimental results and analysis
on how the information generated in the column can be used in the field in the
design and implementation of remediation technologies are presented.

Key words: remediation, cyclic pumping, SVE, vadose zone, heterogeneities.

Poster presentation.

77 • SPREADING OF DENSE NONAQUEOUS PHASE LIQUIDS IN RANDOMLY
HETEROGENEOUS AQUIFERS: EXPERIMENTS ON MULTIPLE REALIZATIONS

R. Compos, T.H. Illangasekare,and H. Rajaram, Department of Civil,
Environmental, and Architectural Engineering, University of Colorado, Boulder,
CO, 80309

A significant fraction of nonaqueous phase fluids remains entrapped in the
spread-zone of heterogeneous aquifers, long after the spill. In our past
research we have shown that in spill experiments with structured
heterogeneities, saturations within the region of entrapment varied from
residual to almost full saturation. Estimation of the highly variable saturation
field is of value in the context of remediation design. Initial DNAPL spill
experiments in a large two-dimensional tank packed to represent a random
heterogeneity demonstrated that pore-scale fingering played a critical role in
the movement and final entrapment distribution of the chemical. This final
entrapment distribution exhibited a random pattern. To avoid the generation of a
large amount of waste and to allow for the possibility of conducting a number of
experiments, a smaller glass-lined tank with the dimensions 4 ft x 3 ft was
constructed. Spill simulations were conducted on randomly-generated
heterogeneous packing configurations. Packing used in each spill simulation
represented a realization of the same stochastic parameters of the random field.
A dual-gamma system was used to determine the final entrapment distribution of
the DNAPL. In this paper, we present the results of these multiple realization
experiments. The data is analyzed to determine the stochastic parameters of the
random entrapment distribution. This data is expected to be used in the
validation of a macro-scale network model that can be used to predict the
distribution of DNAPLs in heterogeneous formations.

Key words: organic waste, dense nonaqueous phase liquid entrapment, effective
parameters, remediation design.

Poster presentation.

78 • CHARACTERIZING AQUIFER HETEROGENEITY USING HYDRAULIC
AND TRACER TESTS: EXPERIMENTAL AND COMPUTATIONAL STUDIES

H.-C. Chao, H. Rajaram, and T.H. Illangasekare, Department of Civil,
Environmental, and Architectural Engineering, University of Colorado, Boulder,
CO, 80309-0428

It is well established that heterogeneities in aquifer properties have an
important influence on field-scale contaminant transport, both for miscible and
immiscible contaminants. The detailed characterization of aquifer heterogeneity,
such as those accomplished at the Borden and Cape Cod sites, among others, is
relatively time-consuming and expensive. An alternative approach is to determine
statistical parameters characterizing the heterogeneity distribution using
indirect methods such as forced-gradient pressure tests and tracer tests. In
such an approach, careful attention must be given to a host of scale issues. For
instance, a tracer test over a scale comparable to or smaller than the
characteristic scale of variability will not yield much information on the
heterogeneity. Therefore, it is possible that a successful approach should
involve tracer tests on several scales.

In this investigation, we present experimental and computational studies
examining the use of tracer tests for characterizing aquifer heterogeneity. The
experimental studies involve pressure and tracer tests conducted in an 8'x4'
laboratory tank, packed with soils in a randomly heterogeneous configuration.
The random hydraulic conductivity distribution was generated using a computer
algorithm. Natural gradient and forced-gradient tests were conducted in the test
aquifer, and the data are used to estimate the mean, variance, and correlation
scales of the hydraulic conductivity distribution. The reliability of the
estimates is investigated via computational experiments on multiple realizations
of the random field with the same statistical parameters as in the laboratory
tank. Implications for the use of these tests at the field-scale are discussed.

Key words: aquifer heterogeneity, effective parameters, contaminant
transport, remediation design.

Poster presentation.

79 • REDUCTIVE DECHLORINATION OF CARBON TETRACHLORIDE USING
ZERO-VALENT METALLIC ELECTRODES

Z. Liu1, R.G. Arnold1, and E.A. Betterton2,
1Department of Chemical and Environmental Engineering and
2Department of Atmospheric Sciences, University of Arizona, Tucson,
AZ, 85721

An electrochemical batch reactor was set up to investigate the dechlorination
of carbon tetrachloride (CT). Various zero-valent metallic foils were used as
the cathodic electrodes, and platinized platinum foil was the counter electrode.
At the cathodic electrode, CT was reduced to chloroform, dichloromethane, and
eventually to methane. Ethylene, ethane, propane, etc., were identified as
byproducts during the dechlorination process indicating that free-radical
reactions are among the chemical conversions at the cathode surface. Reaction
rate was first-order in CT and depended on electrode materials, cathodic
potential, surface area of the cathode, and pH. At a cathodic potential of -1.0V
(vs. SHE) and pH 7.0, nickel was the most reactive of the electrodes tested (k =
9.0 min-1.m-2; Ni>Co>Cu>Fe>AI). When the
working electrode was comprised of copper, 85% of the CT converted yielded
products that were completely dehalogenated. More negative cathodic potentials
produced higher reaction rates until mass transfer limits were encountered at
E£-1.4V (vs. SHE). A model was developed to describe the kinetics of CT
degradation.

Key words: reductive dehalogenation, remediation, ground water, elemental
metals.

Poster presentation.

80 • A COMBINED PLASTICITY/DAMAGE MODEL FOR CREEP OF ROCK
SALT

Z. Chen, M.L. Wang, and T. Lu, University of New Mexico, Engineering
Research, Albuquerque, NM, 87131

Natural salt deposits are considered a desirable host rock for permanent
disposal of radioactive waste because the creep response of rock salt allows the
closure of the disposal room, leading to eventual encapsulation of the
radioactive waste and minimizing the possibility of leakage and contamination to
the environment. An attempt is made in this project to formulate a constitutive
model to describe the creep mechanisms of rock salt. To meet safety and
regulatory requirements, the long-term performance of bedded salt deposit must
be predicted with a high degree of confidence. However, it is impossible to
obtain the long-term performance result from tests. It is only possible to
predict the long-term performance based on its short-term performance result. A
constitutive model derived from the short-term performance is constructed to
fulfill this requirement. Since the failure of materials is considered, the
tertiary stage of creep process must be included. As observed from micro- and
macro-experiments, the transition between the secondary and tertiary stages of
rock salt creep is characterized by localized damage. The reduction in net
loading area under constant creep load will result in the acceleration of damage
and final dynamic crack growth. In order to predict the complete creep process
in a continuum sense, a combined rate-dependent plasticity/damage model is
developed in this project. The experimental data are used to verify the model in
the uniaxial stress state and triaxial stress state.

Key words: rock salt, creep, radioactive waste.

Poster presentation.

81 • MECHANISMS GOVERNING THE REMOVAL OF WASTE FROM A WASTE
REPOSITORY CAUSED BY EXPLORATORY DRILLING

M.L. Wang, X.M. Chen, M.A. Starnes, and J. Berglund, University of New
Mexico, Albuquerque, NM, 87131

This report describes the theoretical basis of the GASFLOW computer code
which was written to calculate the quantity of radioactive material brought to
the surface from a radioactive waste disposal facility due to an inadvertent
drilling intrusion. The GASFLOW computer code determines the amount of material
removed by gas blowout (several other release mechanisms are reported by NMERI
[Berglund, 1993]). The GASFLOW computer code was written specifically for the
computations required for the performance assessment of the Waste Isolation
Pilot Project (WIPP) but with due care can be used for the prediction of gas
emission in coal mines also. The final product of decomposed and compacted
transuranic waste is currently unknown. As a result, waste surrogate materials
are needed to study the mechanical properties of the decomposed waste. This
report outlines the mechanical properties of three surrogate materials developed
with different percentages of crushed salt, clay, and silica sand.

Key words: GASFLOW, radioactive waste, drilling.

Poster presentation.

82 • ADAPTIVE CONTROL OF CONSTRAINED ROBOTIC SYSTEMS FOR
WASTE MANAGEMENT APPLICATIONS

R. Colbaugh and G. Gallegos, Department of Mechanical Engineering, New Mexico
State University, Las Cruces, NM, 88003

The U.S. Department of Energy is presently involved in a comprehensive
program of environmental restoration and waste management (ER&WM), and has
identified robotics as a major technology to be utilized in this waste
management effort. In particular, robotic handling of hazardous waste has been
targeted as an essential element in the solution of many ER&WM problems of
national importance. Included among these problems are the remediation of waste
storage tanks, the retrieval and repackaging of buried waste, the minimization
of waste produced, the decontamination and decommissioning of inactive DOE
facilities, and the handling and inspection of waste within repositories. The
rationales for using robotic systems in these waste management operations are
many, and include the desire to remove humans from hazardous environments, to
reduce the cost of the operations, and to increase the speed with which the
operations can be performed. Unfortunately, experience with the application of
robotic systems to the handling of hazardous waste is quite limited in the U.S.
The majority of robots in operation today are fixed-base manipulators performing
simple, repetitive tasks in highly structured surroundings with no direct
interaction with the environment. This is in contrast to the waste handling
applications mentioned above, which will require both robotic arms and mobile
robots to perform complex tasks involving significant interaction with their
environment and which will demand that these complex tasks be completed despite
considerable uncertainty regarding the system and its environment.

One of the more challenging aspects of robotic waste handling is the problem
of controlling the robotic system in a satisfactory manner. Contributing to the
difficulty of this control problem is the inherent difficulty of accurately and
robustly controlling robotic systems in the presence of measurement and model
uncertainty. It is well-known that control schemes which require precise
knowledge of the complete system model to provide good performance suffer from
many serious limitations. Additionally, it is usually unrealistic to assume that
the entire system state can be accurately measured and used for feedback;
indeed, although high-precision sensors are available for measuring the
configuration of robotic systems, rate measurements are typically either
contaminated with noise or not available at all. These facts provide much
motivation for developing control methods which can be successfully implemented
despite model and state uncertainties. Note that this challenging problem
becomes even more difficult when the motion of the system is constrained in some
way.

Previous studies of robotic waste management have clearly demonstrated that
successful implementation of robotic systems for hazardous waste handling will
require that these systems be capable of performing complex tasks while
subjected to holonomic or nonholonomic (nonintegrable) constraints on the system
kinematics. Consider, for example, tasks such as cutting, grinding, swiping, or
mechanical assembly, which require a robot manipulator to come into contact with
its environment. Such tasks restrict the motion of the manipulator end-effector,
thereby imposing a set of holonomic constraints on the manipulator kinematics.
As a consequence, the constrained robotic system evolves on a submanifold of the
original (unconstrained) configuration space. The control problem in this case
becomes one of controlling the motion on the reduced configuration space while
simultaneously regulating the constraint forces which result from the
interaction between the end-effector and the environment. This problem has
received much attention during the past decade, and numerous results have been
obtained. Here we simply note that the model is precisely known and that the
entire system state is measurable. Observe that these assumptions are not
satisfied in most robotic waste handling applications. Robotic systems with
nonholonomic constraints on the kinematics are also quite common. For instance,
these constraints arise in systems with rolling contact, such as wheeled mobile
robots and multifingered robotic hands, and in systems for which the dynamics
admit a symmetry, such as robots operating in failure mode. Most of the work
reported to date on controlling nonholonomic robotic systems has focused on the
steering or trajectory generation problem in which the system velocities are
considered to be the control inputs, and the mechanical system dynamics are
ignored. Work at the dynamic control level, where the control inputs are those
actually produced by the system actuators and the system model contains the
mechanical system dynamics, has been more limited. Moreover, virtually all of
the control strategies proposed to date have been developed by assuming perfect
knowledge of the system model and state. Recall that these assumptions are not
appropriate for most robotic waste handling tasks.

This paper considers the problem of controlling holonomic and nonholonomic
robotic systems performing waste management operations in the presence of
measurements and model uncertainty, and presents a class of adaptive controllers
as a solution to this problem. The proposed control strategies provide simply
and robust solutions to a number of important robotic system control problems,
including position/force stabilization of holonomically constrained robots,
equilibrium manifold stabilization of systems with nonholonomic constraints, and
equilibrium point stabilization of nonholonomic systems. All of the schemes are
computationally efficient, are implementable without system dynamic model or
rate information, and ensure uniform boundedness of all signals and accurate
motion control. Computer simulation results are provided to complement the
theoretical developments.

Key words: robotic systems, waste management, holonomic constraints.

Poster presentation.

83 • ADSORPTION OF COPPER IONS FROM SOLUTION BY HEAVY METAL
STRESSED-LARREA TRIDENTATA (CREOSOTE BUSH) BIOMASS

J.L. Gardea-Torresdey, J. Bibb, K.J. Tiemann, J.H. Gonzalez, and J.L. Arenas,
Department of Chemistry, The University of Texas at El Paso, El Paso, TX, 79968

Larrea tridentata (creosote bush) were found naturally growing in
heavy metal-contaminated soils. Samples of Larrea tridentata were
collected from six different locations to study their ability to bind copper
ions from solution. Samples from the same locations were either oven dried at
90°C or lyophilized in order to determine differences in drying conditions.
Batch laboratory experiments were conducted with the leaves of Larrea
tridentata in order to determine pH profiles, time dependency, and total
copper binding capacity. It was determined by the pH profile experiments that
the optimum copper binding pH was between 5 and 6. A maximum adsorption of
copper ions was observed within five minutes of reaction time for most of the
biomass collected from the various sites. The copper binding capacity
experiments showed that one gram of biomass can bind as much as 23.7 mg and as
low as 13.4 mg of copper. The capacity to bind copper ions by the biomasses
varied according to the location of the sample site. These differences in
capacities correlate with the distances from the collection site to the possible
contamination source. The closer the sample to the possible source, the greater
the copper binding capacity. Future studies will include batch laboratory
experiments for copper binding by the roots and stems from the various
locations, as well as binding abilities for other metals.

Key words: Larrea tridentata, phytoremediation, copper, metal binding.

Poster presentation.

84 • STRONG OXIDANTS FOR ORGANIC WASTE DESTRUCTION FROM
OXIDATION OF MANGANESE HYDROXIDE

D.K. Cha and S.-M. Park, Department of Chemistry, University of New Mexico,
Albuquerque, NM, 87131

The electrochemical oxidation of manganese hydroxide has been studied in 0.10
M KOH solutions at manganese electrodes employing a variety of electrochemical
techniques in an effort to obtain strong oxidants including manganese
oxyhydroxide, manganese dioxide, and permanganate, which are proposed to be used
for destruction of organic wastes, and to elucidate mechanisms involved therein.
The charge transfer process was shown to be affected by the film formed on the
electrode surface during redox processes. Electrode potentials for redox
processes between manganese hydroxide and higher valence oxides, as well as the
manganese metal, have been assigned. Strong oxidants such as manganese
oxyhydroxide, manganese dioxide, and permanganate were easily obtained by the
oxidation of manganese hydroxide. Diffusion coefficients and an exchange rate
constant for redox processes are also reported.

Key words: oxidation, manganese hydroxide, organic waste.

Poster presentation.

85 • NEW APPROACHES FOR ELEMENTAL SPECIATION STUDIES

J.A. Caruso, Department of Chemistry, University of Cincinnati, P.O. Box
210172, Cincinnati, OH, 45221-0172

Plasma source mass spectrometry (plasma MS) is a state-of-the-art technique
for ultra-trace level elemental analyses. Coupled with the ability to determine
selected isotopes and to perform multielement analysis, it is rapidly becoming a
major analytical technique. Since this is also an element-specific technique, it
has high potential for selective chromatographic detection to obtain speciation
information along with the total trace element profile. The coupling of
different chromatographic methods with plasma source mass spectrometry provides
selectivity necessary and analyses at levels less than or equal to sub-ng to
sub-pg amounts.

Low-volume and low-flow chromatographic methods favor the plasma experiment
and allow structural, as well as quantitative, information. Gas or supercritical
fluid chromatography are low-flow, low-volume methods and provide levels of
detection in the pg to sub-pg range. Recently we have been exploring glow
discharges for GC detection. The rf glow discharge operates at low powers and
can utilize helium or argon gases. The GD sufficiently ionizes the sample for MS
detection at low levels. It also provides structural information at the same
levels. A further departure is to utilize low-pressure helium ICP-MS for
elemental speciation studies. The LP-ICP provides detection levels similar to
the helium glow discharge and also provides structural information. These two
plasma types will be compared and contrasted for their potential as detectors
for elemental speciation studies.

Key words: plasma source mass spectrometry, elemental speciation,
chromatographic detection.

Poster presentation.

86 • BIOLOGICAL AND CHEMICAL NITRATE REMOVAL USING
AUTOTROPHIC DENITRIFIERS AND ZERO-VALENT IRON

B.A. Till1, L.J. Weathers2, and P.J.J.
Alvarez1, 1The University of Iowa, Department of Civil and
Environmental Engineering, Iowa City, IA, 52242, and 2University of
Maine, Department of Civil and Environmental Engineering, Orono, ME, 04469

Nitrate is a priority pollutant due to its potential to cause
methemoglobinemia (i.e., blue baby syndrome). There is also circumstantial
evidence linking ingestion of nitrate to gastric cancer and birth defects.
Nitrate contamination is a major water quality problem in agricultural regions.
In Iowa, 1 million tons of nitrogen are applied each year, and several public
water supplies (~ 60) and private wells (>1,000) exceed the drinking water
standard (45 mg/l as NO3- or 10 mg/l as N). While numerous
physical-chemical and biological processes have been developed to remove nitrate
from water, many of these processes are marginally cost-effective and/or have
detrimental side-effects on water quality. Consequently, there is a need to
explore novel alternatives to remove nitrate from water and wastewaters. This
project investigated the feasibility of combining a novel chemical process
(reductive treatment with zero-valent iron, Fe°) with a biological process
(denitrification with autotrophic, hydrogen-utilizing denitrifiers).

Abiotic nitrate removal by various Fe° sources was investigated in batch (235
ml) serum bottles capped with MininertR valves. Iron powder (Aldrich
Chemical Co.) exhibited faster rates for both nitrate removal and
(water-derived) H2 production as compared to Fe° filings. This was
attributed to the higher specific surface area available for reaction in the Fe°
powder. The more reactive Fe° powder, however, had an apparent toxic effect on
bacteria. Thus, chemoautotrophic denitrifiers had a much higher beneficial
effect when combined with Fe° filings than with Fe° powder. For microbial seeds,
we used both axenic cultures of Thiosphera pantotropha (ATCC35512) and
Paracoccus denitrificans (ATCC17741), and mixed cultures of indigenous
aquifer denitrifiers that had been enriched with H2 and nitrate.

To demonstrate that Fe° was serving as the ultimate electron donor and energy
source for biological denitrification, we used a dual-flask apparatus similar to
that used by Lacy Daniels to demonstrate "Bacterial Methanogenesis and Growth
from CO2 with Elemental Iron as the Sole Source of Electrons"
(Science, v. 237, pp. 509-511, 1987). Two 250 ml Erlenmeyer flasks were
fused at the top with glass tubing. An opening was made on the side of each
flask for sample addition or removal. One of the flasks contained 10 g of Fe°
and 100 ml of water, and the other flask contained 100 ml of mineral media with
nitrate (40 mg/l as N). The flasks were purged with N2/CO2
(80:20, v/v) following inoculation with P. denitrificans. This setup
permitted the diffusion of water-derived H2 from the Fe°-containing
flask through the connecting glass tubing to the seeded flask while avoiding
potential microbial inhibition by iron species. Nitrate was removed below
detection limits within 5 days in this apparatus. No nitrate removal or
microbial growth was observed in control runs, lacking either Fe° or inoculum.

In summary, proof of concept was obtained that Fe° can reduce nitrate
abiotically, and that this process can be enhanced by the presence of
autotrophic denitrifiers. Specifically, Fe° can reduce water to H2,
which is utilized as an electron donor by autotrophic denitrifiers to reduce
nitrate to harmless N2. The high diffusivity of H2 and the
relatively low production of soluble microbial products by autotrophs suggest
the feasibility of using autotrophic denitrifiers Fe° to remove nitrate from
drinking water, either in ex situ reactors or in situ reactive
filters for contaminated ground water.

Key words: autotrophic denitrification, hydrogen, iron, nitrate.

Poster presentation.

87 • DETERMINATION OF THE CONTENT OF HAZARDOUS HEAVY METALS
IN LARREA TRIDENTATA (CREOSOTE BUSH) FOUND NATURALLY GROWING IN
CONTAMINATED SOILS

J.L. Gardea-Torresdey, S. Arteaga, K.J. Tiemann, J. Bibb, and J.H. Gonzalez,
Department of Chemistry, The University of Texas at El Paso, El Paso, TX, 79968

The content of copper, lead, cadmium, and nickel in tissues of Larrea
tridentata (creosote bush) found naturally growing in a contaminated area
was determined by Atomic Absorption Spectroscopy. The area was divided into six
sections, and each section was studied individually. Separate analyses were
performed for the Larrea roots, stems, leaves, as well as for the soils
in which the plants grew. Lead concentrations in roots, leaves, and stems were
650 mg/kg, 150 mg/kg, and 110 mg/kg, respectively, while copper concentrations
were 953 mg/kg, 493 mg/kg, and 370 mg/kg, respectively. In contrast, cadmium
concentrations were lower and varied from 30 mg/kg in the roots, 37 mg/kg in the
leaves, and 10 mg/kg in the stems. The content of nickel determined in
Larrea ranged from 27 mg/kg in the roots, 23 mg/kg in the leaves, and 10
mg/kg in the stems. The soil concentrations where Larrea grew were high
for lead and copper, 5,067 mg/kg, and 4,933 mg/kg, respectively. In contrast,
lower concentrations were found in the soil for cadmium and nickel, 117 mg/kg
and 17 mg/kg, respectively. The heavy metal content of the soils indicates the
degree of pollution in the area. As it was expected, those sections which
contained higher levels of heavy metals in the soil also showed to have higher
heavy metal uptake by the various parts of Larrea tridentata. These data
demonstrate Larrea tridentata's ability to uptake copper and lead, and to
some extent cadmium and nickel, from heavy metal-contaminated soils. Analyses of
other heavy metals will also be examined.

Key words: Atomic Absorption Spectroscopy, heavy hazardous metals, pollution,
Larrea tridentata, environmental analyses.

Poster presentation.

88 • MODELING THE ROLE OF MICROORGANISMS IN THE MOVEMENT OF
LEAD IN UNSATURATED REGION

K.V. Nedunuri, R.S. Govindaraju, and L.E. Erickson, Kansas State University,
Manhattan, KS, 66502

Movement of lead through the vadose zone of soil is influenced by the
presence of organic matter and microorganisms. Among the different microbial
species that exist in the soil rhizosphere, algae is known to accumulate heavy
metals significantly. The metal uptake by algae arises from two processes: a
rapid passive uptake due to surface binding on the cell walls, and a subsequent
slow active uptake due to transport of metal to the interior of the cell. The
passive uptake of lead is modeled as an instantaneous reaction, while the active
uptake is modeled as a complex kinetic reaction. Monod's model is used to
describe the growth kinetics of the algal species. Organic matter serves as the
substrate for the algae. The effect of adsorption of lead, under different
growth conditions of algae in the vadose zone, is studied through model
simulations.

Key words: vadose zone, modeling, microorganisms, heavy metal uptake,
adsorption kinetics.

Poster presentation.

89 • NATURAL BIOVENTING REMEDIATION FROM TIDAL WAVE ACTION
AT A FIELD SITE

D.H. Kampbell, National Risk Management Research Laboratory, U.S. EPA, Ada,
OK, 74820

A remediation research study has been implemented at a jet fuel spill site on
an island airport. The fracture of a buried pipeline resulted in a fuel spill
several years ago exceeding 100,000 gallons. The site hydrogeology is a
fragmented coral matrix with fresh water overlying more dense salt water. Water
table fluctuations of two feet occur once every twelve hours from tidal action.
The research approach being pursued is to pump off free-floating fuel and use a
natural bioventing process caused by tide oscillations to remediate the site.
Initial soil gas measurements have determined that oxygen in the vadose zone
increased as the tide drops and carbon dioxide, along with methane, increased as
the tide rises.

Key words: jet fuel, tide action, bioventing.

Poster presentation.

90 • CHARACTERIZATION OF PARA AND META
PCB-DECHLORINATING ANAEROBIC COMMUNITIES BY 16S rRNA GENES

B.A. Till1, L.J. Weathers2, and P.J.J.
Alvarez1, 1The University of Iowa, Department of Civil and
Environmental Engineering, Iowa City, IA, 52242, and 2University of
Maine, Department of Civil and Environmental Engineering, Orono, ME, 04469

To determine if changes in dechlorinating activity reflected changes in
microbial structure, we compared the distribution of 16S rRNA genes in PCB
dechlorinating consortia. Community DNAs were purified from a para-(#7)
and a meta-(#10) consortium. 16S rRNA genes were PCR amplified with two
primers based on conserved regions of eubacterial 16S rRNA genes. PCR amplified
16S rRNA genes (1.5 kb size) were cloned into PCR II vector (39 kb size) using
TA Cloning Kit (Invitrogen). Clones were screened for inserts by X-gal
complementation and direct-colony PCR. The 15 kb inserts were verified as 16S
rDNAs by hybridization with 32p labeled rDNA probes. Twenty-three-para
and twenty-five-meta clones were digested with Rsa I and
Eco RI in combination to generate RFLP patterns. Based on the restriction
patterns, clones were sorted into 12 operational taxonomic units (OTUs). The
most abundant OTU was significantly different between the para and
meta communities suggesting changes in community structure.

Supported in part by the R2D2 program of the Great Lakes and Mid-Atlantic
Hazardous Substance Research Center, and partly by grants received from NIGMS
(NIH) to SKD.

Key words: OTUs, 16S rDNA, polychlorinated biphenyls dechlorination.

Poster presentation.

91 • AIR-SPARGED HYDROCYCLONE TECHNOLOGY FOR ENVIRONMENT
APPLICATIONS

Y. Yi, Advanced Processing Technologies, Inc., P.O. Box 58131, Salt Lake
City, UT, 84158-0131

There are a wide variety of radioactive, toxic, heavy metal, oil, VOC, and
DNAPL contaminants in the ground waters and soils at a variety of government
and/or industrial facilities. Clean-up of these contaminants is a difficult
task. First, it is a great challenge to remove each individual contaminant by an
individual technology. Second, many sites are contaminated by multicontaminants,
not a single compound at each site. To decontaminate a site containing
multicontaminants, a combination of different types of technologies/equipment is
needed. This practice significantly raises the cost in decontamination process
and causes a complexity and difficulty of the process as compared with a single
technology for a single application which is already a difficult task.

In view of the above situations, Advanced Processing Technologies, Inc. (API)
is developing a differential separation concept, i.e., using one key technology
to process/remove different contaminants step-by-step through proper engineering
and circuit design. The successful development of such a technology/circuit will
significantly reduce the complexity, capital equipment cost, and operation cost
during the decontamination process. The technology in consideration is the
air-sparged hydrocyclone technology which currently is protected by six U.S.
patents and many foreign filings. Application of the technology in environmental
fields has been under the development by APT during the past several years, and
the technology has been demonstrated to have diversified functions to remove
different contaminants from different streams. This may provide a unique
opportunity and offer a strong potential for the removal of heavy metals, VOCs,
oil, DNAPLs, and others from contaminated soil and ground water through a
differential removal process.

Key words: air-sparged hydrocyclone technology, multicontaminants.

Poster presentation.

92 • BIOLOGICAL TREATMENT OF AIR STREAMS CONTAMINATED WITH
ORGANIC VAPORS

F.G. Edwards1, N.N. Khandan1, and J.M.
Phalen2, 1Civil Engineering Department 3CE, New Mexico
State University, P.O. Box 30001, Las Cruces, NM, 88003, and 2Sandia
National Laboratories, Environmental Restoration Technologies Department,
Albuquerque, NM, 87185

The clean-up of soils contaminated with organic chemicals, such as fuels or
solvents, is often accomplished by soil venting. The subsequently contaminated
air is typically treated when pumped through granular activated carbon (GAC),
which adsorbs the contaminants from the air. When the adsorptive capacity of the
GAC is exhausted, the carbon can be reactivated and the pollutant oxidized using
thermal processes, which are expensive. An innovative method of reactivating the
carbon and oxidizing the pollutant is to use microbes which utilize the
pollutant as a food source. The goal of this research is to determine if a
three-phase, fluidized, up-flow bioreactor is a viable treatment method for
treating air-streams which are contaminated with organics; and to define design
and operational parameters of the bioreactor.

Initial studies consisted of theoretical process modeling to define the
transfer of the contaminant from the gas phase, transfer of oxygen to the liquid
phase, uptake of oxygen by the microbes, adsorption of the contaminant by the
activated carbon, and utilization of the contaminant by the microbes.

Bench-scale studies were undertaken to determine the range of velocities
required to fluidize the GAC (using various combinations of water and air), to
determine the adsorptive capacity of the GAC versus contaminant concentration
for each pollutant, and to develop a microbial population which can utilize each
of the pollutants. Further bench-scale studies have been undertaken to determine
the BOD of the pollutants, to determine the rate of utilization of the
contaminant by the microbes, and to determine the rate of increase in the
microbial population. In addition, bench-scale studies were conducted to
determine the parameters of the theoretical model.

Current research has validated and fine-tuned the proposed model using
pilot-scale reactors and three organic chemicals. Removal efficiencies for the
three chemicals tested range up to 95%. It is intended to validated field
conditions using a pilot-scale reactor, which will be located at Sandia National
Laboratories Mixed Waste Landfill.

Key words: activated carbon, airlift bioreactor, airstreams, BETX, biological
treatment, modeling, organic vapors.

Poster presentation.

93 • ULTRASONIC ENHANCEMENT FOR IN SITU REMEDIATION
OF CONTAMINATED SOIL

H.J. Fernandez and D. Hanesian, New Jersey Institute of Technology, CEES
Building, 138 Warren Street, Newark, NJ, 07102

The objective of the present study is to use ultrasonic energy as an
enhancing technique for in situ remediation of organic contaminants.
Ultrasonic waves will be coupled with soil fracturing techniques to desorbed
contaminants from the low permeability formations. It is believed that doubling
the detoxification rate may be possible. This would cut the treatment time in
half, thus realizing a significant savings in labor and operational costs. A
portion of these savings will be offset by the capital cost of the ultrasound
generators and the power requirements, but these are anticipated to be modest.
It is expected that the coupling of ultrasound with the proven process of soil
fracturing will yield positive, enhanced results.

Key words: ultrasound, soil fracturing, enhancement.

Poster presentation.

94 • NOVEL CHOLINE ESTERASE-BASED SENSOR FOR MONITORING OF
ORGANOPHOSPHORUS POLLUTANTS

E. Wilkins, A.L. Ghindilis, and P. Atanasov, Chemical & Nuclear
Engineering Department, University of New Mexico, Albuquerque, NM, 87131

Organophosphorus compounds are significant major environmental pollutants due
to their intensive use as pesticides. Potentiometric electrodes based on
detection of choline esterase inhibition by analytes has been developed. The
detection of choline esterase activity is based on the novel principal of
molecular transduction. Immobilized peroxidase acting as the molecular
transducer catalyzes the electroreduction of hydrogen peroxide by direct
(mediatorless) electron transfer. The sensing element consists of a carbon-based
electrode containing an assembly of co-immobilized enzymes: choline esterase,
choline oxidase, and peroxidase. The enzymes catalyze a sequence of
reactions.

Two of these reactions result in the formation of hydrogen peroxide and lead
to a change of the electrode potential. The potential shifts towards equilibrium
H2O2/H2O potential due to a third reaction
catalyzed by peroxidase. The rate of the potential change is proportional to the
activity of choline esterase.

The sensing elements development involved screening of different carbon-based
electrode materials, modification of electrode surface, and testing of different
types of chemical immobilization. For electrode material selection, a number of
different carbon-based compounds were screened and tested. These involved carbon
fiber, felt and matt, graphite materials, and some highly dispersed carbon
materials.

The immobilization of enzymes was conducted utilizing commercially-available
materials. The effect of electrochemical pretreatment of these materials was
also studied. Different techniques of enzyme immobilization were used for
sensing element fabrication, and the results were compared. Immobilization
techniques were based on physical sorption and chemical binding of enzyme amino
groups to modified and unmodified carbon surface.

Butyryl choline sensitive three-enzyme electrode has been developed employing
highly dispersed carbon as an electrode material. Immobilization procedure is
based on physical adsorption of peroxidase and co-immobilization of choline
oxidase and choline esterase by glutaraldehyde technique. The electrode remains
100% active during one month storage at 4ºC. The procedure for measuring the
electrode activity requires 2-3 min.

Incubation of the electrode in a solution containing organophosphorus
pesticide trichlorfon for 10 min. results in notable decrease of electrode
activity. This allows determination of sub-micromolar concentration of
pesticide.

The application of the biosensor described above is associated with the
monitoring of the organophosphorus pesticide pollutants in sampled soils,
streams, and ground and waste waters. One of the most important preventive
measures in this case is to rapidly determine the source of the pollutant and
the magnitude of threat from on-site measurements.

Key words: sensor, organophosphorus compounds, choline esterase, enzyme.

Poster presentation.

95 • POLYMER GEL AS A BARRIER FOR GROUND OIL SPILL
CONTAINMENT

J.C. Miller and E. Wilkins, Department of Chemical & Nuclear Engineering,
University of New Mexico, Albuquerque, NM, 87131

Testing and development of technology to contain ground chemical and oil
spills continues as a result of local and national concerns. These concerns
arise from increased environmental awareness, directed toward the preservation
of water quality and the restoration of contaminated surface and ground waters.
Preventing petroleum slop oil and sludges and other waste fluids from leaching
into the surrounding subsurface environment has become a growing concern.
Contaminants can migrate to aquifers, thereby risking contamination of city
drinking water, as well as rural aquifers. Contaminants in subsurface water also
pose threats to agricultural activities, rapidly migrating higher up the food
chain from plants. One possible solution is to employ a polymer gel as an
impervious barrier between the contaminants and adjacent soil and ground water.
The barrier can prevent leakage from accidents during transport, leaking from
storage tanks, accidental discharges, etc.

Chemical dump sites as well as oil spills occurring in off-shore drilling may
contaminate the shoreline several feet below the surface after preliminary
clean-up has been accomplished. Since New Mexico does not have seas or large
rivers in which oil spills might occur, this work will concentrate exclusively
on containment of ground oil spills or chemical leakage from old or illegal dump
sites. Further, in New Mexico there are many thousands of abandoned mines, mine
dumps, and mill tailings ponds. Every one of these has the potential to become a
hazard to human activities and to the environment. This class of problem is
typical of those existing regionally, nationally, and even internationally.

The primary objective of this work is to develop a viscous polymeric gel to
act as a sponge to absorb chemical leakage, i.e., effluent from industries and
dump sites, and contain oil which has seeped into the ground from a spill of a
leaking tank, or from oil transportation. The barrier will be formed by
injection into the ground of ungelled and (hence low viscosity) polymer, which
will then gel in controlled fashion. Injection of low viscosity fluid
significantly reduces operating costs. This study developed several promising
polymer gels and concentrated on the study of PAA gel cross-linked by different
cross-linking agents. It was found that the gelation time can be easily
controlled by the ungelled solution pH. The polymer gel barrier can decrease the
permeability of sites significantly, to the order of 10-8 to
10-9 cm/s, which is much lower than the criterion for an ideal
barrier. However the diffusivities of small molecules, in the polymer gel, such
as dissolved petroleum hydrocarbon components is not much lower than in water.
Even though over 95% of gel components are water, the cross-linked gel structure
should retard diffusion more than water.

Key words: polymer gel, oil spill, water, agriculture.

Poster presentation.

96 • DEVELOPING A SITE-WIDE HAZARDOUS WASTE MINIMIZATION
PROGRAM

R. Railan, Office of Cost and Performance Analysis (EM-15), U.S. Department
of Energy, Washington, DC, 20585

The U.S. Environmental Protection Agency announced in March 1990, that in
order to protect the nation's ground water, waste containing 25 toxic organic
chemicals are now subject to safeguards of federal hazardous waste regulations.
These chemicals are known to have contaminated ground water at hazardous waste
sites.

The new rule increased the quality of non-wastewaters waste by 1.8 million
metric tons per year. Additionally, 700 metric tons of wastewater was also
affected. Much of that volume, however, is already managed in wastewater
treatment tanks approved under the Clean Water Act.

With this rule 17,000 additional generators were to be affected including a
variety of industries. As a result approximately 200 surface impoundments
currently used to dispose of the waste also will be regulated under RCRA for the
first time.

Estimated total costs of compliance range from $650 to $800 million a year.

Disposal of hazardous waste generated by the Department of Energy (DOE) will
cost us, DOE and the taxpayers, millions of dollars every year. Substantial
costs include environmental compliance, disposal, and liability. We have reacted
to this problem by prescribing many remedies to try to solve it, i.e., HW
treatment and reclamation facilities, and recycling and recovery facilities.

There is a need to develop a strong and cost-effective site-wide hazardous
waste minimization program across the DOE complex, by taking the following
steps: (1) define the program scope and objectives, (2) obtain and demonstrate
top management support, (3) establish a HAZMIN (hazardous waste minimization)
working group, (4) conduct a HAZMIN survey, (5) develop and implement a HAZMIN
management plan, (6) develop Department's commitment to the HAZMIN program, (7)
implement selected HAZMIN projects, and (8) track progress and reevaluate
program scope and objectives.

Key words: waste minimization.

Poster presentation.

97 • NAVAJO NATION-BASED, CROWNPOINT INSTITUTE OF
TECHNOLOGY'S ENVIRONMENTAL TECHNOLOGY PROGRAM

S. Chischilly, Crownpoint Institute of Technology, Crownpoint, NM, 87313-0849

The Crownpoint Institute of Technology (CIT), located on the Navajo (Diné)
Nation, is currently developing an Environmental Technology program scheduled to
begin in fall semester 1996. This program will allow post-high school Native
American students to become skilled in environmental sampling techniques, data
collection, and long term monitoring via hands-on field training, classroom
presentation, and through cooperative agreements with tribal programs,
businesses, industry, and other educational institutions on and off the Navajo
Nation. Areas of study will focus on technical courses to meet the needs of
tribal environmental programs, environmentally-oriented businesses, and
natural-resource production or extraction companies throughout the Navajo Nation
and southwestern United States.

Courses include Native American environmental remediation/restoration
perspectives, hazardous materials, environmental regulations, asbestos and lead
abatement, mining safety, HAZWOPER, introduction to radiation, solid waste
management, emergency response, technical mapping, bioremediation, and an
internship program. Graduates will be able to apply their knowledge in positions
which do not necessarily require a four-year degree, but do require thorough
environmental sampling knowledge, with an understanding of environmental laws,
and the ability to communicate findings accurately.

Key words: Native American, environmental technology, Navajo Nation.

Poster presentation in Native American session.

98 • HERS: A CENTER FOR RESEARCH, EDUCATION, AND
COMMUNICATION

W.M. Griswold1, G.L. Godfrey1, S.C. Grant2,
and P.T. Yazzie1, 1Haskell Indian Nations University,
Department of Natural and Social Sciences, Lawrence, KS, 66046, and
2Great Plains/Rocky Mountain Hazardous Substance Research Center,
Kansas State University, Manhattan, KS, 66506-2502

The Haskell Environmental Research Studies Center (HERS), located at Haskell
Indian Nations University, Lawrence, Kansas, was created as a center for
environmental research, education, and communication for Native American
colleges, universities, and tribes. HERS, in conjunction with the Great
Plains/Rocky Mountain Hazardous Substance Research Center (HSRC), administers
the Native American and Other Minority Institutions (NAOMI) program. NAOMI was
created to increase the involvement of minority educational institutions in
research, training, and technology transfer activities. NAOMI will begin funding
its first training program in May 1996. The program's goal is to create a HACH
training center at Sinte Gleska University, Rosebud, South Dakota, and is a
joint project between SGU and Navajo Community College, Shiprock, New Mexico.
NAOMI is also continuing to coordinate a Summer Cooperative Research Program.
This program matches NAOMI faculty and students with HSRC-funded research
projects at other universities. Another primary element of the NAOMI program is
a seminar series that provides education on hazardous substances and related
environmental issues. HERS distributes the seminars through the use of
videotapes and satellite downlinks. NAOMI links research, training, technology
transfer, and education activities through the publication of a bimonthly
newsletter, Earth Medicine, which reports on HERS and NAOMI activities to
Native American colleges and universities, tribal offices, HSRC members,
environmental firms, and EPA regional offices. HERS also coordinated a two-week
environmental technology workshop for Native American and other minority
students during summer 1995. HERS has also established a relationship with
Boeing Commercial Airplane Group to provide an internship program for Haskell
Indian Nations University faculty and students.

Key words: Native American, research, technology transfer.

Poster presentation in Native American session.

99 • ENVIRONMENTAL CONCERNS ON THE OSAGE RESERVATION

J.O. Bear, Haskell Indian Nations University, Division of Natural Sciences,
155 Indian Avenue, Box 1227, Lawrence, KS, 66046-4800, e-mail:
[email-masked]

The Osage Indian Reservation, containing 1.5 million acres, is located in
northeastern Oklahoma. Extensive oil production occurring over more than a
100-year period has brought forth hydrocarbon and heavy metal contamination of
soil and water environs.

Key words: hydrocarbon contamination, ground water, pollution prevention.

Poster presentation in Native American session.

100 • NAVAJO STUDENTS MONITOR A LOCAL URANIUM-MILL TAILINGS
SITE

C. Brown1, M. Mitchell1, W. Pierce1, B.
Tsosie2, and S.C. Semken1, 1Navajo Dryland
Environments Laboratory, Navajo Community College, Shiprock, NM, 87420-0580,
e-mail: [email-masked], and 2Department of Earth and
Environmental Sciences, New Mexico Institute of Mining and Technology, Socorro,
NM, 87801

Navajo geoscience students are actively involved in the long-term monitoring
of ground water quality at an abandoned uranium-mill tailings (UMTRA) site in
the Diné (Navajo) Nation community of Shiprock. Ground-water contamination by
suspected mill effluents and extreme proximity to the San Juan River, a major
surface-water resource, render this a site of great environmental concern to the
U.S. Department of Energy (DOE) and the Navajo Nation government, which share
jurisdiction. Supported by a research grant from the DOE through the
Waste-management Education and Research Consortium (WERC) and University of New
Mexico, the students have received training in health and safety protocols,
water-table measurement, ground water sampling, and geochemical analysis. Their
work includes collection and interpretation of hydrogeological data that are
used by DOE and Navajo agencies to guide ongoing remediation efforts at the
site, and by WERC university partners to support postgraduate research. The
students also participate in local community-awareness activities related to the
project and its environmental consequences, and receive academic credit.

Key words: environmental education, uranium, remediation, Navajo.

Poster presentation in Native American session.

101 • MONITORING AND MINIMIZING AIR POLLUTANTS FROM PAINTS
USED AT TURTLE MOUNTAIN MANUFACTURING COMPANY, BELCOURT, ND

C. Disrud and J. Desjarlais, Turtle Mountain Community College, Belcourt, ND,
58316-0340

Turtle Mountain Manufacturing Company (TMMC) is a metal-fabrication
manufacturer located on the Turtle Mountain Indian Reservation. Its primary
customer is the Department of Defense, which requires Chemical Agent coatings on
contracted products such as water tanks and trailers that were used in "Desert
Storm." The problem is that hazardous pollutants such as chloromethane or
benzene may be emitted into the atmosphere by the venting system, but TMMC does
not have the trained personnel nor the equipment to measure them. TMMC therefore
does not have a procedure for air pollution control, and neither does the Turtle
Mountain Band of Chippewa Indians.

Key words: Native American, chemical, source reduction.

Poster presentation in Native American session.

102 • AIR QUALITY AND RESPIRATORY HEALTH OF SHIPROCK
(NAVAJO NATION) RESIDENTS: PRELIMINARY STUDIES OF METEOROLOGICAL AND HEALTH DATA

D. ManyCattle and R. Srivastava, Navajo Dryland Environments Laboratory,
Navajo Community College, Shiprock, NM, 87420-0580, e-mail:
[email-masked]

Respiratory illness is a significant problem among Native Americans, and is a
major cause of mortality. This is also true on the Navajo Nation in general and
more so in the Shiprock area of the Navajo Nation. We suspect that ambient and
indoor air qualities have a role in this, specifically in terms of particulate
concentrations and the unique location of Shiprock in the San Juan River valley.
As a part of a long-term study on respiratory health and air quality (indoor and
ambient), we have initialized preliminary work on studying wind patterns and
fuel use for cooking and home heating. These preliminary results will be
presented. Health data, if accumulated and analyzed by May, will also be shared.

Key words: air quality, respiratory health, Navajo.

Poster presentation in Native American session.

103 • EARTH SYSTEMS AND NAVAJO PEDAGOGY

S.C. Semken1 and F. Morgan2, 1Navajo Dryland
Environments Laboratory and 2Center for Diné Studies, Navajo
Community College, Shiprock, NM, 87420-0580, e-mail: [email-masked]

Introductory geoscience at Navajo Community College, which is operated by and
serves an exclusively Native American community, is taught using an Earth
systems framework, wherein Earth materials, processes, and history are
interpreted as the result of interacting solid-Earth (endogenic) and fluid-Earth
(exogenic) processes. This pedagogy has first-order parallels in the Diné
(Navajo) philosophy of nature, which attributes Hózhó or balance in the surface
environment to processes of renewal driven by interactions between Nohosdzáán
(Earth environment) and Yádilhil (sky environment). Second-order parallels
between Diné models of equilibrium and perturbation and Euro-American models
such as Le Châtelier's principle can be employed to teach geochemical cycles and
processes such as weathering and metamorphism. Diné cultural content is to be
reinforced through local field study and the use of appropriate cultural and
linguistic references. The parallel use of Diné and Euro-American scientific
concepts at Navajo Community College is intended to reinforce student
understanding of, and to stimulate thinking and discussion of, ethnogeological
concepts that have long been known to traditional Diné culture.

Key words: Navajo, education, Earth systems, geoscience.

Poster presentation in Native American session.

104 • DEVELOPMENT OF ENVIRONMENTAL TECHNOLOGY CURRICULUM
FOR NATIVE AMERICAN COLLEGES

K. Topper1, M. Gilfillan2, F. Morgan3, R.
Srivastava3, R. Walker1, and S.D. Wolf3,
1Mesa State College, Grand Junction, CO, 81501, 2RUST
Geotech, Grand Junction, CO, 81502-5504, and 3Navajo Dryland
Environments Laboratory, Navajo Community College, Shiprock, NM, 87420-0580

There have been very few efforts to develop Environmental Technology
curricula for Native American community colleges, despite a history of
environmental pollution and related problems on Native American lands. This
project, funded by National Science Foundation ATE DUE grant #9454633, is
developing a comprehensive curriculum package that specifically addresses
American Indian environmental pollution problems. A significant portion of this
project is focused upon incorporation of American Indian cultural values within
this technologically-oriented field. A workshop was held at Crownpoint Institute
of Technology to initiate the cultural inclusion, followed by a questionnaire
and further development by the authors. This presentation will provide an
overview of this project and results obtained to date. We encourage input from
any interested people.

Key words: Native American culture, environmental technology.

Poster presentation in Native American session.

105 • COMMUNITY WORKSHOPS IN NAVICULTURE, TRADITIONAL
PLANNING, AGRICULTURE, AND COMMUNITY ENVIRONMENTAL PLANNING WITHIN THE SHIPROCK
AREA OF THE NAVAJO NATION

S.D. Wolf, Navajo Dryland Environments Laboratory, Navajo Community College,
Shiprock, NM, 87420-0580, e-mail: [email-masked]

This presentation will comprise summaries of: the goals behind the various
workshops, the information presented, and the outcomes of the workshops. In
addition, newsletters, questionnaires, and other information will be available.

The Naviculture workshop focused on philosophies and techniques which
encourage planning for, and managing, natural resources to meet human needs with
low-impact, low-cost methods. The Traditional Planning workshop discussed the
difficulties in bringing together Western and traditional Navajo planning and
problem-solving. Agriculture workshops were conducted to define collaborative
agricultural projects within the Shiprock community. The Community Environmental
Planning workshop provided a basic overview of the planning process,
environmental considerations in planning, and hands-on exercises in some of the
fundamentals of planning.

Key words: environmental planning, community, agriculture, Navajo.

Poster presentation in Native American session.

106 • NAOMI SEMINAR PROGRAM: EXPLORING NATIVE ENVIRONMENTAL
ISSUES THROUGH VIDEO COMMUNICATION

P.T. Yazzie1, W.M. Griswold1, G.L. Godfrey1,
and S.C. Grant2, 1Haskell Indian Nations University,
Department of Natural and Social Sciences, Lawrence, KS, 66046, and
2Great Plains/Rocky Mountain Hazardous Substance Research Center,
Kansas State University, Manhattan, KS, 66506-2502

The Haskell Environmental Research Studies Center (HERS), located at Haskell
Indian Nations University (HINU), Lawrence, Kansas, was created as a center for
environmental research, education, and communication for Native American
colleges, universities, and tribes. HERS, in conjunction with the Great
Plains/Rocky Mountain Hazardous Substance Research Center (HSRC), administers
the Native American and Other Minority Institutions (NAOMI) program. NAOMI was
created to increase the involvement of minority educational institutions in
research, training, and technology-transfer activities concerning hazardous
substances. One of the primary elements of NAOMI is a seminar program that
provides public education on hazardous substances and related environmental
issues. HERS distributes the seminars through the use of videotapes and
satellite downlinks. The seminar series targets students and faculty from
minority institutions and mainstream institutions, tribal leaders and
professionals, and the general public. Speakers for the seminar series include
Native American professionals working in environmental fields with Native
American tribes, environmental professionals, and faculty associated with the
HSRC consortium. The seminar series includes issues such as the use of natural
resources and the effects of that use on tribal life, pollution prevention,
comparison of Native and Western views of nature, and a "Gathering for the
Earth." The latter was part of the 25th anniversary of Earth Day in Washington,
DC. In April 1996, HERS will sponsor the first satellite uplink from the HINU
campus focusing on water quality, landfills, the ramifications of using
traditional Native American lands for military purposes, and the effects of
mining activities on tribal life.

Key words: Native American, research, technology transfer.

Poster presentation in Native American session.

107 • EFFECT OF PNEUMATIC FRACTURING ON AN EXISTING
STRUCTURE

I. Nelson, M. Canino, and J.R. Schuring, Pneumatic Fracturing Research Group,
Hazardous Substance Management Research Center, Department of Civil and
Environmental Engineering, New Jersey Institute of Technology, Newark, NJ, 07102

Pneumatic fracturing is a technique used to enhance various environmental
remediation technologies. It is particularly effective at sites with low ground
permeability. Often such sites are located in urban areas adjacent to, or even
within, existing structures. There is concern as to the potential structural
effect caused by pneumatic fracturing adjacent to existing structures.

The current poster outlines a research study on an existing structure, the
former Midland-Ross site in Highland Park, NJ. An injection well was placed
within an abandoned warehouse. Limited data, including strain measurements, were
taken during fracture. As part of study, an attempt also was made to create a
structural model of the steel frame and masonry building. The project attempts
to bracket the numerous uncertainties involved and to correlate the numerical
and experimental results. Hopefully, broader implications to other structures
would follow

Key words: pneumatic fracturing, structural modeling.

Poster presentation in R2D2 session.

108 • POTENTIAL OPTIONS & MANUFACTURING CHANGES FOR
ETHYL ETHER IN SUPPORT OF POLLUTION PREVENTION

I.B. Zimmer, Emission Reduction Research Center, New Jersey Institute of
Technology, University Heights, Newark, NJ, 07102-1982

This project focuses on replacing or eliminating the use of ethyl ether in
Department of Defense systems (e.g., weapon systems, ammunition manufacturing,
propellant manufacturing, and processing). An analysis of the processes using
ethyl ether, a search for substitutions, and a review of modern techniques are
central to this project. The results and procedures form the basis for broader
application and chemical change. All conclusions and recommendations require
laboratory verification.

Key words: ether, solvent, extraction, peroxide, volatile.

Poster presentation in R2D2 session.

109 • PNEUMATIC FRACTURING COMPUTER MODEL

B.M. Sielski and J.R. Schuring, New Jersey Institute of Technology, Center
for Environmental Engineering and Science, 138 Warren Street, Newark, NJ, 07102

Pneumatic fracturing technology is now receiving considerable industrial
attention since it addresses a problem which has plagued environmental clean-up
efforts to date, i.e., remediation of low permeability geologic formations. Now
that pneumatic fracturing is commercialized, there is an increasing need for a
comprehensive computer model to aid in analysis. The computer model will be
useful in deciding whether a site is a potential candidate for the technology.
Presently, these decisions are made by informal comparisons with empirical data
from past projects. The model will be programmed using Microsoft Visual Basic
and have a Windows interactive interface.

The computer model will quantitatively compare geological properties and
confirm applicability for a particular site. Once it is established that
pneumatic fracturing is appropriate for a site, the model will be applied to
preliminary design and estimation of parameters such as well spacing, injection
pressure, and fracture interval. It could also be used to estimate the degree of
enhancement of formation permeability and mass removal rate which may be
expected. The user can investigate four principal model components: site
screening, fracture propagation, fracture flow and transport, and supplemental
injection.

Key words: pneumatic fracturing, computer model, VBasic.

Poster presentation in R2D2 session.

110 • INVESTIGATION INTO FRACTURE BEHAVIOR AND LONGEVITY OF
PNEUMATICALLY-FRACTURED FINE-GRAINED FORMATIONS

H.A. Hall, J.R. Schuring, and T.M. Boland, New Jersey Institute of
Technology, Center for Environmental Engineering and Science, 138 Warren Street,
Newark, NJ, 07102

Pneumatic fracturing is an enhancement technology for in situ
remediation of hazardous waste sites. It is most effective in improving the rate
and efficiency of cleanup of low permeability formations when integrated with
primary remediation technologies such as extraction, thermal treatment, and
bioremediation. Changes in fracture aperture, or thickness, will significantly
affect permeability rates reflecting changes in remediation efficiency.

This study investigated the effect of volume changes in fine-grained soil
formations and their effect on pneumatically-induced fractures. A number of
formation properties (i.e., physical, chemical, and mineralogical properties)
and environmental conditions (e.g., moisture, pore fluid composition, surcharge
pressure) were identified which affect fracture aperture.

Laboratory tests were first performed with control devices to investigate
idealized fracture flow under linear and radial flow geometries. The experiments
were then expanded to study volume changes in a natural soil which contained an
artificial discrete fracture. A laboratory device termed a horizontal
infiltrometer was developed to induce and control volume changes with moisture
as the major variable.

A new concept of a "secondary active zone" was introduced which describes the
zone of increased activity along the fracture boundary soils. A classification
model was developed for assessing volume change potential using soil properties.
The model also presents potential treatment alternatives including hydraulic
control, chemical stabilization, and fracture propping.

Future work includes modeling changes in fracture aperture over time in low
permeability soils using one-dimensional consolidation theory. Additional
laboratory bench-scale tests will be performed with a variety of soil types and
environmental conditions. The predicted volume changes will then be correlated
with the experimental results and applied to a field case study.

Key words: clay, fracture, volume change, remediation.

Poster presentation in R2D2 session.

111 • USE OF IN SITU OZONATION FOR THE REMEDIATION
OF CONTAMINATED SOILS

D. Cole, S. Masten, and S. Davies, Department of Civil and Environmental
Engineering, Michigan State University, East Lansing, MI, 48824

Chemical oxidation may be used to overcome the limitations imposed by the low
aqueous solubility of polycyclic aromatic hydrocarbons (PAHs) on their rates of
biodegradation and dissolution. The objective of this study is to evaluate the
effectiveness of using ozone for chemical oxidation of PAHs in soils from sites
contaminated with jet fuel at Wurtsmith Air Force Base. The degradation of ozone
in the soil, the effects of organic matter on ozone stability, and the effect of
ozonation on the microbial community in the soil were investigated.

Key words: ozone, soil remediation, oxidation processes, hydrocarbons.

Poster presentation in R2D2 session.

112 • EFFECTS OF LAKE/AQUIFER INTERACTIONS ON THE
BIOTRANSFORMATION OF CHLORINATED SOLVENTS DISCHARGING TO THE LAKE

S.M. Dean and N.D. Katopodes, Department of Civil and Environmental
Engineering, University of Michigan, Ann Arbor, MI, 48109-2125

Contamination of ground water by chlorinated solvents is widespread and has
been in the forefront of public and regulatory concern for the last decade. As a
result, considerably research efforts, both in the laboratory and in the field,
have addressed the potential for using biological processes to degrade these
pollutants via in situ, or on site, bioremediation technologies. Natural
attenuation has been observed to be responsible for removal or partial
transformation of both chlorinated and non-chlorinated organic contaminants. At
several sites, naturally-occurring reductive dechlorination has been found to be
responsible for the transformation of trichloroethylene (TCE) to lesser
chlorinated intermediates, such as c- and t-dichloroethylene (DCE) and vinyl
chloride (VC), and to ethylene. Since contaminated aquifers can become
oxygenated near ground water/lake interfaces, concerns have been raised with
respect to surface water contamination by VC. At a National Priority List site
near St. Joseph, Michigan, sequential geoprobe samples taken in the immediate
vicinity of Lake Michigan suggest that lake water may be recirculating through
the aquifer. In the current study, a modeling approach addresses the fate of TCE
and its lesser chlorinated transformation products at this anaerobic/aerobic
interface. The modeling effort describes and predicts the fate of the
chlorinated solvents at and near the interface, taking into account ground water
flow rates and microbial degradation rates, as well as the oxygenating effects
from wave action and lake water intrusion near the shore line. Possible causes
of lake water recirculation through the aquifer are investigated.

Key words: chlorinated solvents, lake, aquifer, biotransformation.

Poster presentation in R2D2 session.

113 • EFFECT OF ELECTRON DONOR AND ELECTRON ACCEPTOR
CONCENTRATIONS ON REDUCTIVE DECHLORINATION RATES OF TCE AT A SULFIDOGENIC GROUND
WATER/SURFACE WATER INTERFACE

J.M. Lendvay and P. Adriaens, Environmental and Water Resources Engineering,
The University of Michigan, Ann Arbor, MI, 48109-2125

Iron- and sulfate-reduction have been shown to be the predominant terminal
electron-accepting processes at the interface between a trichloroethene (TCE)
contaminated aquifer and Lake Michigan at the St. Joseph, Michigan, NPL site.
Our current research is aimed at evaluating the effect of electron donor and
acceptor concentrations on sulfate-reduction and reductive dechlorination rates
of TCE under sulfate-reducing conditions at this interface.

Batch microcosms consisting of sediment and ground water from the ground
water/surface water interface are amended with 1.0 mM TCE in addition to an
energy source and electron acceptor. Concentrations of energy source and
electron acceptor are varied to evaluate resulting kinetic effects on the
reductive dechlorination of TCE. Specifically, this study utilizes lactate as an
energy source (0.2 mM to 2.0 mM) while sulfate concentrations are maintained in
excess. Similarly, sulfate concentrations are varied between 0.2 mM and 2.0 mM
while maintaining lactate concentration in excess. This experimental approach
simulates in situ subsurface conditions as soluble sulfate concentrations
range from 0.2 mM to 1.25 mM, and available electron equivalents of COD are in
the mg/kg (sediment) range. Additionally, soluble hydrogen gas is measured to
evaluate the transition to hydrogen as an election donor. Preliminary results
have shown reductive dechlorination of tetrachloroethene (PCE) to vinyl chloride
(VC) under sulfidogenic conditions using sediment and ground water from this
same ground water/surface water interface.

Key words: sulfate reduction, reductive dechlorination, bioremediation.

Poster presentation in R2D2 session.

114 • SORPTION OF PHENANTHRENE BY NATURAL AND SYNTHETIC
ORGANIC MATRICES

E.J. LeBoeuf, W. Huang, and W.J. Weber, Jr., Department of Civil and
Environmental Engineering, The University of Michigan, Ann Arbor, MI, 48109-2125

It has long been recognized that the natural organic matrices (NOM) of soils,
sediments, and aquifer materials play a major role in the fate and transport of
organic contaminants in subsurface systems. Processes involving the slow
sorption of organic solutes onto and into these matrices and subsequent
hysteretic desorption from them are believed to be principally responsible for
the failure of conventional pump-and-treat remediation technologies. Although a
clear understanding of the characteristics of natural organic matrices has not
yet been achieved, increasing evidence indicates the presence of two primary
domains, one consisting of a relatively labile, swollen, rubber-like phase, and
the other a resistant, condensed, glass-like phase, similar to the rubbery and
glassy thermodynamic states of synthetic organic polymers. In this study,
sorption of phenanthrene on natural and synthetic organic matrices was conducted
to ascertain the influence each of these domains has on sorption capacity and
linearity.

Our hypothesis contends that soil organic matrices (SOM) are composed of
components of each of these domains, and that the rubbery-like domain is
primarily responsible for the partitioning behavior evidence by linear
isotherms, with the more condensed SOM largely controlling the adsorption
behavior evidenced by nonlinear isotherms. This hypothesis is further supported
by the dual-mode sorption behavior of synthetic organic polymers. The dual-mode
model assumes the presence of a partitioning domain and a Langmuir adsorption
domain within a glassy polymer. However, as a glassy polymer transcends to a
more rubbery state through swelling or increased temperature, the Langmuir
adsorption sites are replaced by a larger partitioning domain, ultimately
resulting in a completely rubbery polymer, leaving only a partitioning domain
and completely linear isotherm behavior.

The hypothesis was tested by sorbing phenanthrene in aqueous suspensions of
natural and synthetic organic matrices at 5ºC and 25ºC. Natural sorbents
included a soil humic acid, two kerogens from shales, and two coals. Synthetic
sorbents included a number of poly(methacrylates) exhibiting a range of glassy
to rubbery thermodynamic states.

Results of this study support our hypothesis. As expected, the rubbery
poly(methacrylates) showed linear isotherms at all temperatures, while the more
glassy polymers showed highly nonlinear behavior at the lower temperature, and
decreased nonlinearity at the higher temperature. Swollen humic acids in aqueous
solution behaved similarly to rubbery polymers, exhibiting almost pure
partitioning at both temperatures, whereas the more condensed kerogens and coals
are significantly more nonlinear, exhibiting a larger Langmuir adsorption domain
at the lower temperature compared to the higher temperature.

Key words: sorption, remediation, soil, aquifer.

Poster presentation in R2D2 session.

115 • FOURIER TRANSFORM INFRARED SPECTROSCOPIC AND
ELLIPSOMETRIC STUDIES OF EXOPOLYSACCHARIDE AND BIOFILM ATTACHMENT ON SILICA

D.A. Buttry1, S.J. Clay1, J.P. Turner2, and
L.A. Bulla3, 1Department of Chemistry,
2Department of Civil Engineering, and 3Department of
Molecular Biology, University of Wyoming, Laramie, WY, 82070

Biofilms are being investigated as a potential barrier to hazardous
materials. These biofilms are comprised of microcolonies containing bacteria and
exopolysaccharides (EPS). This EPS is thought to mediate adhesion of the
bacteria to minerals surfaces. With this biofilm, an initially porous soil
matrix can become very impermeable, effectively producing a barrier. In this
study, Fourier transform infrared spectroscopy (FTIR) and ellipsometry were used
to monitor the growth rate and attachment of a Beijerinckia indica
biofilm to a silicon dioxide (quartz) substrate. By monitoring absorption bands
previously attributed to exopolysaccharides, the accumulation of the EPS on the
silicon dioxide substrate could be studied. In conjunction with the FTIR
measurements, ellipsometry was used to determine the thicknesses of the biofilm
and EPS.

Key words: biofilm, exopolysaccharides, bacterial adhesion.

Poster presentation in R2D2 session.

116 • PROPOSED STUDIES IN SURFACTANT-ENHANCED
BIOREMEDIATION OF ORGANIC CONTAMINANTS

J.A. Mitzel, R.A. Doughten, R.E. Macur, H.M. Gaber, and W.P. Inskeep, Plant,
Soil, and Environmental Sciences Department, Montana State University, Bozeman,
MT, 59717

The bioavailability of nonpolar organic compounds (NOCs) in soils will
influence the rate at which bioremediation will occur. The use of surfactants to
enhance the apparent bioavailability is currently being reviewed to determine if
this is a viable method for bioremediation of sites contaminated with NOCs.
Presently, we are conducting research on the use of surfactants for enhancing
biodegradation and transport of NOCs in soils. To date, we have found limited
success enhancing biodegradation rates, but show dramatic increases in
surfactant-enhanced solute transport. Our future research will concentrate on
the influence of surfactant chemistry on the enhanced solubility of NOCs such as
phenanthrene and pentachlorophenol, and the subsequent biodegradation of these
compounds. The effect of nonaqueous-phase liquids (NAPLs) on surfactant-enhanced
bioremediation and the effect of known phenanthrene degraders on sites
containing NAPLs will also be studied. The information gained from this future
research will help provide information concerning remediation strategies using
surfactants.

Key words: bioremediation, bioavailability, nonaqueous phase liquids,
nonpolar organic compounds.

Poster presentation in R2D2 session.

117 • FENTON OXIDATION TO REMEDIATE RDX-CONTAMINATED WATER
AND SOIL

E.L. Bier, S.D. Comfort, and P.J. Shea, Department of Agronomy, University of
Nebraska, Lincoln, NE, 68583-0915

Some soils at the former Nebraska Ordnance Plant (NOP) and other military
installations are highly contaminated with cyclonite (RDX) as a result of past
waste management practices. Since RDX is mobile in soil and recalcitrant at high
concentrations, these sites may require remediation to reduce potential health
and environmental hazards resulting from contamination of water supplies.
Conventional treatment by incineration is very costly and often creates strong
public opposition. We propose an alternative treatment using the Fenton reagent
(Fe2+ + H2O2) to remediate RDX-contaminated
water and soil. Treating an aqueous solution of RDX (35 mg l-1) with
the Fenton reagent resulted in complete RDX destruction within 24 h. Mass
balance experiments with 14C-RDX indicated 75 to 85% was lost as
14CO2, while 10% was lost as volatile 14C
organic compounds. After 24 h of Fenton oxidation, end products include
NH4+, NO3-, and formic acid. An
additional 14C degradation product found in solution is being
isolated for identification. Results from Fenton oxidation of RDX-contaminated
soil from the NOP site will also be reported.

Key words: RDX, Fenton oxidation, remediation.

Poster presentation in R2D2 session.

118 • OVERVIEW OF KANSAS EPA EPSCoR PROJECTS

R. Peat and A.P. Schwab, Kansas State University, Agronomy Department,
Throckmorton Hall, Manhattan, KS, 66506

The Experimental Program to Stimulate Competitive Research (EPSCoR) is a
program for states under-funded in the national research arena. Kansas
EPA-funded EPSCoR projects are a focused effort to enhance bioremediation
research by giving young scientists the opportunity to become part of a
state-wide team. The universities involved in this team effort are Kansas State
University, the University of Kansas, and Wichita State University.

This poster presentation will provide an overview of three Kansas EPA EPSCoR
projects. These projects examine (1) the bioremediation of petroleum
hydrocarbons in the subsurface environment, (2) the use of vegetation to
stabilize and remediate sites contaminated with heavy metals, and (3) the role
of methanotrophic bacteria in remediation of surface aquatic environments.

Key words: bioremediation, EPSCoR, heavy metal, hydrocarbons, ground water
quality, surface water quality, soil.

Poster presentation in R2D2 session.

119 • THE EFFECTS OF THE RHIZOSPHERE ON THE OXIDATION STATE
OF CHROMIUM IN SLUDGE-AMENDED SOILS

C.T. Henderson, M.K. Banks, and A.P. Schwab, Kansas State University,
Manhattan, KS, 66502

The effect of plant root interactions with chromium sludge-amended soils on
the mobility of chromium will be assessed to quantify the change in oxidation
state and distribution of chromium in the soil profile. Effects of pH and soil
and rooting depth will be determined. This study will evaluate the effectiveness
of using plant roots to change the oxidation state of chromium in contaminated
surface soil.

Key words: chromium, mobility, adsorption, contamination, soil, heavy metal.

Poster presentation in R2D2 session.

120 • COMETABOLISM OF TRICHLOROETHENE (TCE) IN
FLUIDIZED-BED BIOREACTORS

R.L. Segar, Jr., S.A. Vivek, K. Leung, P. Kalia, K.L. Bauman, and J.R.
Foeller, Department of Civil Engineering, University of Missouri-Columbia,
Columbia, MO, 65211

The development of fluidized-bed bioreactors (FBBRs) for the treatment of
water contaminated with chlorinated solvents offers a promising alternative to
existing treatment technologies. The objectives of this research are to develop
two different fluidized-bed reactors, a conventional single-pass reactor and an
innovative draft-tube reactor, for the removal of trichloroethene (TCE) from
ground water and to understand how the design of each reactor type affects the
TCE removal. Phenol was selected as the growth substrate for activated sludge
microorganisms because it induces enzymes with the ability to cometabolize TCE
and its daughter products.

Experiments with the conventional reactor have focused on the effect of TCE
loading, phenol loading, detention time, and pulsed feeding techniques.
Preliminary studies included fluidization studies with various filter sand types
and grades, aeration studies with a downflow-bubble-contactor, conductivity
tracer studies, TCE abiotic loss rate studies, and batch TCE degradation
studies. Results of these studies are being used to develop a basic design
approach for cometabolizing bioreactors and a detailed, non-steady-state model
of biofilm reactors fed multi-component mixtures of toxic organics.

Sand was selected as the attached media for the conventional FBBR, which had
dimensions of approximately 5 cm diameter and 100 cm of bed depth. At a flow
rate of 0.8 l/min, the continuous-flow TCE removals indicated that the proper
level of phenol feeding was essential for obtaining high TCE removal. A phenol
to TCE mass ratio of 50:1 provided 70-80% removal of 0.1 mg/l TCE at an EBCT of
3 minutes. Phenol was not detected in the reactor effluent at those conditions.
Subsequent studies with TCE-amended ground water addressed means to improve TCE
removal by increasing the reactor length, using denser media, and optimizing the
phenol feeding rate. The performance of the FBBR for TCE removal was superior to
other types of biological reactors reported in the literature.

Key words: biofilm, fluidized-bed, trichloroethene, phenol, ground water
remediation.

Poster presentation in R2D2 session.

121 • MIXING AND AGITATION IN SLURRY REACTORS FOR
BIOREMEDIATION

M. Farraro, R.K. Bajpai1, G.W. Preckshot, and S.K. Banerji,
University of Missouri-Columbia, W2030 EBE, Columbia, MO, 65211,
1e-mail: [email-masked]

Slurry bioreactors for environmental restoration have particles of sizes from
microns to several millimeters, difficult suspension characteristics, low to
moderate mass transfer needs, long-term operation, and tight economical
constraints. This presentation will deal with a review of the state-of-the-art
for mixing and agitation of slurries for bioremediation niche. The correlations
relating power supply, agitation, and mass transfer will be summarized and
compared. Soil applications will be explored, and missing information will be
identified.

Key words: mass transfer, design, scale-up, soil, biorestoration.

Poster presentation in R2D2 session.

122 • THE INFLUENCE OF PHOSPHORUS ON CHEMICAL AND
MINERALOGICAL PROPERTIES OF A ZINC/LEAD SMELTER SLAG

M. Lambert1 and G.M. Pierzynski2,
1Department of Geology and 2Department of Agronomy, Kansas
State University, Manhattan, KS, 66506

For many years, zinc and lead ore from the Tri-State region was processed in
a smelter near the village of Dearing, in Montgomery County, southeastern
Kansas. Although the smelter is no longer in operation, remediation of the slag
produced as a waste product by the smelter is a matter of ongoing environmental
concern. X-ray diffractometry was used to determine the mineralogical
composition of untreated slag and slag to which phosphate was added in the form
of fertilizer. The most noticeable difference between the two is that orthoclase
(potassium feldspar) and potassium lead phosphate that is present in the
untreated slag is absent or present in reduced quantities in the treated slag.
Pyromorphite (lead orthophosphate) is present in both, and lead released by the
dissolution of the potassium lead phosphate may be precipitating as additional
pyromorphite.

Key words: Tri-State region, zinc ore, lead ore, slag, potassium lead
phosphate, pyromorphite.

Poster presentation in R2D2 session.

123 • COMPUTER SIMULATION OF THE EFFECT OF VEGETATIVE
REMEDIATION OF SOILS-PROPOSED WORK

W. Guinn, B. Hankley, L.E. Erickson, R.S. Govindaraju, and G.M. Pierzynski,
Kansas State University, Manhattan, KS, 66506

This work will be in support of the Vegetative Interceptor Zones for
Containment of Heavy Metal Pollutants project. One of the goals of this project
is the development of a physically based model of surface movement of heavy
metals in the presence of vegetation/interceptor strips. The main goal of this
work is the development of a tool which would be useful to civil and chemical
engineers in studying the transport of heavy metals. This tool would use
mathematical models developed by Dr. Govindaraju and others. The mathematical
model would be verified using field data developed by Dr. Pierzynski and others.
One initial step is to take a look at what graphical simulations have already
been developed and what kind of interfaces have been used. Potential users of
this tool will be asked for help in developing requirements to be used in
writing specifications, including preferred platform. User friendliness will be
emphasized for easy use. Key areas of modeling include surface and subsurface
modeling such as 2-D overland (water) flow, 2-D soil erosion (sediment), and 2-D
heavy metal transport (solute). Initial work will start simulation in one
horizontal direction. Ultimately, the simulation will provide top, side, and 3-D
views with user-provided inputs for such variables as: field slope, crop (soil
cover), rate of rainfall, duration of rainfall, size of raindrop, impact action
of rain, distance between buffer strips, size of sediment, subsurface loss
(infiltration), size of watershed, and type of soil. Outputs of the simulation
would be heavy metal concentrations and locations.

Key words: computer simulation, vegetative remediation, soil, heavy metal.

Poster presentation in R2D2 session.

124 • SOIL FLUSHING OF HEXACHLOROBENZENE USING SURFACTANT
AND COLLOIDAL GAS APHRONS IN A TWO-DIMENSIONAL SYSTEM

M.L. Smith, Hazardous Substance Research Center, Louisiana State University,
Baton Rouge, LA, 70803

In situ soil flushing with surfactant solution, an enhanced
pump-and-treat process, were examined in this study. The study employed water,
surfactant solution, and colloidal gas aphron suspensions as discrete carriers
for the contaminant. Colloidal gas aphron suspensions were generated using the
surfactant solution. The target contaminant was hexachlorobenzene (HCB). The
removal efficiency and mobilization of the contaminant were investigated using a
two-dimensional cell containing either a homogeneous, contaminated sand bed or
an uncontaminated sand bed with a contaminated soil core. A few different types
of surfactants were used in the study. The system attempted to model conditions
possibly encountered at hazardous waste sites when flushing with water and/or
surfactants to better predict performance in the field.

Key words: soil washing, soil flushing, surfactants, colloidal gas aphron,
remediation.

Poster presentation in R2D2 session.

125 • DETERMINING SOIL CONTAMINANTS USING NEUTRON
ACTIVATION AND GAMMA-RAY SPECTROSCOPY

J. Monzon and D. Heckathorn, TRIGA Mark II Nuclear Reactor Facility, Kansas
State University, Manhattan, KS, 66506

Soil samples were obtained from mining sites in Kansas and Montana. Soil
contaminants were investigated through the use of neutron activation and
gamma-ray spectroscopy. The spectroscopy results obtained from these results
were compared with spectroscopy results from chemical standards, which were
prepared at Kansas State University. A comparison between the count rates of the
soil samples and the chemical standards was conducted to provide quantitative
results. This comparison led to a better understanding of the types and
concentrations of contaminants in the soil samples.

Key words: neutron activation, gamma-ray spectroscopy, soil contaminants.

Poster presentation in R2D2 session.

126 • CONSTRUCTION OF CHLOROBIPHENYL DEGRADATION PATHWAY IN
GRAM + BACTERIUM RHODOCOCCUS ERTHREUS STRAIN NY05

R.R. Helton Coll, T.V. Tsoi, J.F. Quensen III, and J.M. Tiedje, NSF Center
for Microbial Ecology, Michigan State University, East Lansing, MI, 48824

Biphenyl-degrading Gram + bacteria Rhodococcus erythreus strain NY05
is able to co-metabolize a wide range of PCB congeners yielding corresponding
chlorobenzoates. That makes this organism an attractive model for construction
of PCB-degradative recombinant pathways in order to obtain bacteria growing on
PCBs.

We have constructed shuttle vehicle pRT1, which stably maintains in both Gram
- bacteria and R. erythreus, and confers host cells resistance to
tetracycline. Using pRT1 plasmid as a cloning vector, we have constructed
recombinant plasmid pRHD carrying Arthrobacter globiformis fcbABCD operon
controlling hydrolytic para-dechlorination of chlorobenzoates. Plasmid pRHD was
transferred into R. erythreus NY05 using electrotransformation.

Expression of fcbABCD operon currently is under investigation.

Key words: polychlorinated biphenyls, Rhodococcus, degradation,
shuttle vector, gene-cloning.

Poster presentation in R2D2 session.

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