Final Report: The Role of Metallic Iron in the Biotransformation of Chlorinated Xenobiotics
EPA Grant Number: R825549C044Subproject: this is subproject number 044 , 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: The Role of Metallic Iron in the Biotransformation of Chlorinated Xenobiotics
Investigators: Alvarez, Pedro J. , Parkin, G. F. , Schnoor, J. L. , Weathers, L. J.
Institution: University of Iowa
EPA Project Officer: Manty, Dale
Project Period: August 13, 1993 through June 2, 2000
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989)
Research Category: Organic Chemical Contamination of Soil/Water
Description:
Objective:This research investigates the hypothesis that both microbial and abiotic processes contribute to reductive dechlorination of xenobiotics in methanogenic incubations with elemental metals, such as iron, serving as an ultimate electron donor. Summary/Accomplishments (Outputs/Outcomes):
Polychlorinated compounds such as carbon tetrachloride (CT) are known to be transformed via sequential reductive dechlorination by both abiotic and microbial mechanisms under anaerobic conditions. However, existing treatment processes that utilize reductive dechlorination suffer from several drawbacks including inefficient transfer of electrons from the ultimate electron donor to the chlorinated compound and slow rates of reaction, thereby resulting in possible accumulation of transformation products of equal or even greater toxicity. Elemental metals in aqueous solution can act as an energy source for methanogens via production of hydrogen. Using elemental metals as an energy source, reductive dechlorination of chlorinated compounds may proceed by three mechanisms:
1. abiotic processes whereby electrons are transferred directly from the
elemental metal to the chlorinated compound,
2. microbial processes whereby
electrons from hydrogen that are involved in biosynthetic processes are diverted
to the chlorinated compound, and
3. microbially catalyzed abiotic processes
whereby electrons from the elemental metal are transferred to the chlorinated
compound via biological electron carriers.
Experiments were conducted in batch and column-reactor systems. Initial studies investigated Fe(0) and carbon tetrachloride (CT). Various chlorinated organics, nitrate, and RDX were also assayed. Hydrogen-utilizing, mixed, anaerobic cultures were developed as inoculum sources for most experiments. In addition, pure cultures of three methanogens, one denitrifier, and one iron-reducer were used in some experiments. Initial batch studies were performed to determine the general time-course that the reactions would follow. Inhibition studies using 2-bromoethanesulfonate (BES), a specific methanogenic inhibitor, addressed the role of methanogens. Analytes measured in headspace gas samples include CT, chloroform (CF), dichloromethane (DCM), chloromethane (CM), hydrogen, and methane. Subsequent batch experiments assessed a variety of conditions to better understand the versatility and limitations of bioaugmenting Fe(0), including use of pure cultures of bacteria, a wide variety of contaminants (chlorinated ethenes, nitrate, RDX, etc.), and environmental conditions (e.g., pH, redox). The stoichiometry and kinetics of pertinent reactions were determined. Electron balances were conducted to provide insight into important abiotic and biotic processes. Flow-through column experiments using adjustable-bed-length, glass chromatographic columns packed with steel wool were conducted to assess long-term performance. A limited number of column experiments used a mixture of sand and granular iron.
A summary of major findings follows in bullet form. These findings were summarized in detail in our semi-annual progress reports and in the variety of publications and presentations given under the publications listed.
A patent application has been filed for Fe(0)-based remediation. Investigators have made numerous presentations of this research at technical conferences. Results have been published in peer-reviewed journals.
Journal Articles on this Report: 10 Displayed | Download in RIS Format
Other subproject views: | All 47 publications | 11 publications in selected types | All 10 journal articles |
Other center views: | All 900 publications | 231 publications in selected types | All 188 journal articles |
Type | Citation | ||
---|---|---|---|
|
Dejournett TD, Alvarez PJJ. Combined microbial-Fe(0) treatment system to remove nitrate from contaminated groundwater. Bioremediation Journal 2000;4(2):149-154. |
R825549C044 (Final) |
not available |
|
Gregory KB, Mason MG, Picken HD, Weathers LJ, Parkin GF. Bioaugmentation of Fe(0) for the remediation of chlorinated aliphatic hydrocarbons. Environmental Engineering Science 2000;17(3):169-181. |
R825549C044 (Final) R825549C053 (Final) |
not available |
|
Helland BR, Alvarez PJJ, Schnoor JL. "Reductive dechlorination of carbon tetrachloride with elemental iron. Journal of Hazardous Materials 1995;41(2-3):205-216. |
R825549C044 (Final) |
not available |
|
Novak PJ, Daniels L, Parkin GF. Enhanced dechlorination of carbon tetrachloride and chloroform in the presence of elemental iron and Methanosarcina barkeri, Methanosarcina thermophila, or methanosaeta concillii. Environmental Science & Technology 1998;32(10:1438-1443. |
R825549C044 (Final) |
not available |
|
Novak PJ, Daniels L, Parkin GF. Rapid dechlorination of carbon tetrachloride and chloroform by extracellular agents in cultures of Methanosarcina thermophila. Environmental Science & Technology 1998;32(20):3132-3136. |
R825549C044 (Final) |
not available |
|
Parkin GF. Anaerobic biotransformation of chlorinated aliphatic hydrocarbons: Ugly duckling to beautiful swan. Water Environment Research 1999;71(6):1158-1164. |
R825549C044 (Final) R825549C053 (Final) |
not available |
|
Scherer MM, Richter S, Valentine RL, Alvarez PJJ. Chemistry and microbiology of permeable reactive barriers for in situ groundwater clean up. Critical Reviews in Environmental Science & Technology 2000;30(3):363-411. |
R825549C044 (Final) |
not available |
|
Till BA, Weathers LJ, Alvarez PJJ. Fe(0)-supported autotrophic denitrification. Environmental Science & Technology 1998;32(5):634-639. |
R825549C044 (Final) |
not available |
|
Weathers LJ, Parkin GF, Alvarez PJJ. Utilization of cathodic hydrogen as electron donor for chloroform cometabolism by a mixed, methanogenic culture. Environmental Science & Technology 1997;31(3):880-885. |
R825549C044 (Final) |
not available |
|
Wildman MJ, Alvarez PJJ. RDX degradation using an integrated Fe(0)-microbial treatment approach. Water Science and Technology 2001;43(2):25-33. |
R825549C044 (Final) |
not available |
dechlorination, xenobiotics, heavy metals, iron. , Water, Scientific Discipline, Waste, Remediation, Analytical Chemistry, Environmental Chemistry, Contaminated Sediments, heavy metal contamination, xenobiotics, biotransformation, extraction of metals, biotechnology, contaminated sediment, metal contamination, metals, contaminated groundwater, groundwater remediation, metallic ion, chemical contaminants, contaminants
Relevant Websites:
Progress and Final Reports:
Original Abstract
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