Final Report: Fate of Trichloroethylene (TCE) in Plant/Soil Systems

EPA Grant Number: R825549C006
Subproject: this is subproject number 006 , established and managed by the Center Director under grant R825549
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (1989) - Great Plains/Rocky Mountain HSRC
Center Director: Erickson, Larry E.
Title: Fate of Trichloroethylene (TCE) in Plant/Soil Systems
Investigators: Doucette, William J. , Bugbee, Bruce , Stevens, David K.
Institution: Utah State University
EPA Project Officer: Hahn, Intaek
Project Period: September 1, 1996 through September 1, 1999
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text |  Recipients Lists
Research Category: Organic Chemical Contamination of Soil/Water , Land and Waste Management

Objective:

The goal of this research is to 1) investigate the fate of TCE and other chlorinated ethenes in plant/soil systems through a combination of laboratory experiments and mathematical modeling, and 2) to evaluate the applicability of plant-based bioreactor for the remediation of ground water contaminated with TCE.

Summary/Accomplishments (Outputs/Outcomes):

Chlorinated solvents, such as TCE, are among the most frequently found groundwater contaminants at military installations, due to their widespread use in degreasing operations. Understanding the fate of these contaminants is critical in performing the risk assessments and evaluating remediation options. Development of less costly remediation alternatives for contaminated groundwater is also of considerable importance. The uptake into plants is a potentially important fate process that has not been adequately evaluated for TCE and other chlorinated solvents. Determination of uptake rates, plant/water and plant/air distribution coefficients, and degradation rates would greatly improve fate modeling and risk assessment efforts. In addition, the literature indicates that conditions in the rhizosphere may favor co-metabolic transformation of TCE. Phytoremediation has shown promise, but it implementation has been limited, in part due to the difficulties associated with non-engineered systems. The plant-based bioreactor proposed in this study may provide a cost-effective approach for remediating groundwater that is contaminated with TCE and other hazardous organic chemicals. The bioreactor approach enables the control of key environmental variables, such as moisture, nutrients, pH, and oxygen in order to maximize plant and remediation efficiency.

Laboratory studies have been designed to evaluate the fate of chlorinated ethenes in hydroponic systems. Specifically, these studies determine plant/water/air distribution coefficients and plant uptake rates. This approach has been extended to laboratory and field plant/soil systems. Based on the results, a plant-based bioreactor for the remediation of contaminated groundwater has been constructed. Environmental conditions are managed to optimize plant growth and microbial activity.

The first project objective was accomplished with the construction of four plant growth chamber systems. Each chamber system includes 12 traps: two water traps, four TCE traps, four CO2 traps, and two CO2 overflow traps. The system provided high mass recoveries and complete foliar/root separation while maintaining a natural plant environment. Additional details describing the design, operation, and performance of the chamber systems can be found in Orchard et. al. (2000).
The results of the first three chamber studies are described in Doucette et. al. (2000) and can be briefly summarized as follows. [14C]TCE recoveries ranged from 92 to 101% in 11 dosed chambers. TCE mass equivalent concentrations in the shoot tissue (2 to 168 mg/kg) were dependent on the amount of water transpired and the exposure concentration. Root-zone oxygen status did not significantly impact TCE uptake. The transpiration stream concentration factors (TSCFs) determined in these studies ranged from 0.02 to 0.20 and were independent of exposure duration. However, our TSCF values are much less than predicted based on the compound's log Kow value and the empirical relationship for TSCF. It is also considerably lower than the TSCF value reported in the literature for TCE. Potential reasons for these differences are discussed in Doucette et.al. (2000).

In the fourth study, TSCFs for TCE, calculated from total [14C]TCE in shoot tissues plus phytovolatilized 14C, were 0.11 for both 1 ppm treatments and 0.16 for the 10 ppm treatment with roughly 30% attributed to phytovolatilization in all cases. Though extended duration resulted in accumulation of mass of 14C in plant tissues, the TSCF values are within the range of values determined in the first three studies. The TCE metabolites trichloroethanol (TCEt), trichloroacetic acid (TCAA), and dichloroacetic acid (DCAA) were identified in plant tissues of the 10 mg/L treatment.

Two additional studies were performed to quantify the uptake of the non-volatile TCAA and TCEt by hybrid poplar. Unlike the four studies previously described, these studies were performed in open, aerated, hydroponic systems using unlabelled compounds. TSCF values were calculated based on extractable parent compound in shoot tissue. The TSCF for TCEt was <0.01. Presence of TCAA in hydroponics solution and in leaf and root tissues indicated transformation of TCEt to TCAA. The TSCF for TCAA was <0.03 and decreased with increasing exposure concentration likely due to toxicity. The presence of DCAA in leaf and root tissues indicated transformation of TCAA to DCAA. A detailed report describing the results of the fourth closed system chamber sturdy and the two TCE metabolite uptake studies can be found in Chard (1999).

Technology transfer for this project has taken the form of the publications (2 refereed journal articles, 1 article in proceedings, 2 MS thesis) and presentations (6 platform and 5 posters). In addition, several progress reports describing the results of our research were made to the Environmental Management group at Hill Air Force Base.


Journal Articles on this Report : 2 Displayed | Download in RIS Format

Other subproject views: All 16 publications 2 publications in selected types All 2 journal articles
Other center views: All 904 publications 230 publications in selected types All 182 journal articles
Type Citation Sub Project Document Sources
Journal Article Orchard BJ, Douchette WJ, Chard JK, Bugbee B. A novel laboratory system for determining fate of volatile organic compounds in planted systems. Environmental Toxicology and Chemistry 2000;19(4):888-894. R825549C006 (Final)
  • Full-text: Utah State University-Full Text PDF
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  • Abstract: Wiley-Abstract
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  • Journal Article Orchard BJ, Doucette WJ, Chard JK, Bugbee B. Uptake of trichloroethylene by hybrid poplar trees grown hydroponically in flow-through plant growth chambers. Environmental Toxicology and Chemistry 2000;19(4):895-903. R825549C006 (Final)
  • Abstract: Wiley-Abstract
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  • Supplemental Keywords:

    Trichloroethylene, phytoremediation, transport, mass balance., Scientific Discipline, Toxics, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Geochemistry, Contaminated Sediments, Analytical Chemistry, Fate & Transport, Ecology and Ecosystems, Bioremediation, 33/50, fate and transport, degradation, microbiology, contaminant transport, aerobic degradation, microbial degradation, biodegradation, contaminated sediment, hazardous waste, adsorption, chemical transport, hazardous organic substances, bioremediation of soils, chemical kinetics, contaminants in soil, photodegradation, groundwater contamination, 1, 1, 1-Trichloroethane, sorption experiments, phytoremediation, contaminant transport models, bacterial degradation, contaminated soils

    Progress and Final Reports:

    Original Abstract
  • 1997
  • 1998

  • Main Center Abstract and Reports:

    R825549    HSRC (1989) - Great Plains/Rocky Mountain HSRC

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825549C006 Fate of Trichloroethylene (TCE) in Plant/Soil Systems
    R825549C007 Experimental Study of Stabilization/Solidification of Hazardous Wastes
    R825549C008 Modeling Dissolved Oxygen, Nitrate and Pesticide Contamination in the Subsurface Environment
    R825549C009 Vadose Zone Decontamination by Air Venting
    R825549C010 Thermochemical Treatment of Hazardous Wastes
    R825549C011 Development, Characterization and Evaluation of Adsorbent Regeneration Processes for Treament of Hazardous Waste
    R825549C012 Computer Method to Estimate Safe Level Water Quality Concentrations for Organic Chemicals
    R825549C013 Removal of Nitrogenous Pesticides from Rural Well-Water Supplies by Enzymatic Ozonation Process
    R825549C014 The Characterization and Treatment of Hazardous Materials from Metal/Mineral Processing Wastes
    R825549C015 Adsorption of Hazardous Substances onto Soil Constituents
    R825549C016 Reclamation of Metal and Mining Contaminated Superfund Sites using Sewage Sludge/Fly Ash Amendment
    R825549C017 Metal Recovery and Reuse Using an Integrated Vermiculite Ion Exchange - Acid Recovery System
    R825549C018 Removal of Heavy Metals from Hazardous Wastes by Protein Complexation for their Ultimate Recovery and Reuse
    R825549C019 Development of In-situ Biodegradation Technology
    R825549C020 Migration and Biodegradation of Pentachlorophenol in Soil Environment
    R825549C021 Deep-Rooted Poplar Trees as an Innovative Treatment Technology for Pesticide and Toxic Organics Removal from Soil and Groundwater
    R825549C022 In-situ Soil and Aquifer Decontaminaiton using Hydrogen Peroxide and Fenton's Reagent
    R825549C023 Simulation of Three-Dimensional Transport of Hazardous Chemicals in Heterogeneous Soil Cores Using X-ray Computed Tomography
    R825549C024 The Response of Natural Groundwater Bacteria to Groundwater Contamination by Gasoline in a Karst Region
    R825549C025 An Electrochemical Method for Acid Mine Drainage Remediation and Metals Recovery
    R825549C026 Sulfide Size and Morphology Identificaiton for Remediation of Acid Producing Mine Wastes
    R825549C027 Heavy Metals Removal from Dilute Aqueous Solutions using Biopolymers
    R825549C028 Neutron Activation Analysis for Heavy Metal Contaminants in the Environment
    R825549C029 Reducing Heavy Metal Availability to Perennial Grasses and Row-Crops Grown on Contaminated Soils and Mine Spoils
    R825549C030 Alachlor and Atrazine Losses from Runoff and Erosion in the Blue River Basin
    R825549C031 Biodetoxification of Mixed Solid and Hazardous Wastes by Staged Anaerobic Fermentation Conducted at Separate Redox and pH Environments
    R825549C032 Time Dependent Movement of Dioxin and Related Compounds in Soil
    R825549C033 Impact of Soil Microflora on Revegetation Efforts in Southeast Kansas
    R825549C034 Modeling the use of Plants in Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances
    R825549C035 Development of Electrochemical Processes for Improved Treatment of Lead Wastes
    R825549C036 Innovative Treatment and Bank Stabilization of Metals-Contaminated Soils and Tailings along Whitewood Creek, South Dakota
    R825549C037 Formation and Transformation of Pesticide Degradation Products Under Various Electron Acceptor Conditions
    R825549C038 The Effect of Redox Conditions on Transformations of Carbon Tetrachloride
    R825549C039 Remediation of Soil Contaminated with an Organic Phase
    R825549C040 Intelligent Process Design and Control for the Minimization of Waste Production and Treatment of Hazardous Waste
    R825549C041 Heavy Metals Removal from Contaminated Water Solutions
    R825549C042 Metals Soil Pollution and Vegetative Remediation
    R825549C043 Fate and Transport of Munitions Residues in Contaminated Soil
    R825549C044 The Role of Metallic Iron in the Biotransformation of Chlorinated Xenobiotics
    R825549C045 Use of Vegetation to Enhance Bioremediation of Surface Soils Contaminated with Pesticide Wastes
    R825549C046 Fate and Transport of Heavy Metals and Radionuclides in Soil: The Impacts of Vegetation
    R825549C047 Vegetative Interceptor Zones for Containment of Heavy Metal Pollutants
    R825549C048 Acid-Producing Metalliferous Waste Reclamation by Material Reprocessing and Vegetative Stabilization
    R825549C049 Laboratory and Field Evaluation of Upward Mobilization and Photodegradation of Polychlorinated Dibenzo-P-Dioxins and Furans in Soil
    R825549C050 Evaluation of Biosparging Performance and Process Fundamentals for Site Remediation
    R825549C051 Field Scale Bioremediation: Relationship of Parent Compound Disappearance to Humification, Mineralization, Leaching, Volatilization of Transformaiton Intermediates
    R825549C052 Chelating Extraction of Heavy Metals from Contaminated Soils
    R825549C053 Application of Anaerobic and Multiple-Electron-Acceptor Bioremediation to Chlorinated Aliphatic Subsurface Contamination
    R825549C054 Application of PGNAA Remote Sensing Methods to Real-Time, Non-Intrusive Determination of Contaminant Profiles in Soils
    R825549C055 Design and Development of an Innovative Industrial Scale Process to Economically Treat Waste Zinc Residues
    R825549C056 Remediation of Soils Contaminated with Wood-Treatment Chemicals (PCP and Creosote)
    R825549C057 Effects of Surfactants on the Bioavailability and Biodegradation of Contaminants in Soils
    R825549C058 Contaminant Binding to the Humin Fraction of Soil Organic Matter
    R825549C059 Identifying Ground-Water Threats from Improperly Abandoned Boreholes
    R825549C060 Uptake of BTEX Compounds by Hybrid Poplar Trees in Hazardous Waste Remediation
    R825549C061 Biofilm Barriers for Waste Containment
    R825549C062 Plant Assisted Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances: Experimental and Modeling Studies
    R825549C063 Extension of Laboratory Validated Treatment and Remediation Technologies to Field Problems in Aquifer Soil and Water Contamination by Organic Waste Chemicals