Final Report: Fate and Transport of Munitions Residues in Contaminated Soil

EPA Grant Number: R825549C043
Subproject: this is subproject number 043 , 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 and Transport of Munitions Residues in Contaminated Soil
Investigators: Comfort, S. D. , Shea, Patrick J.
Institution: University of Nebraska at Omaha
EPA Project Officer: Hahn, Intaek
Project Period: August 12, 1992 through September 30, 1997
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text |  Recipients Lists
Research Category: Fate and Transport , Land and Waste Management


Goals are to establish accurate predictions of desorption kinetics of munitions residues by elucidating changes in sorption characteristics over time; to characterize transport properties of both freshly added and aged RDX, TNT, and principal degradates; and to predict the fate and transport of munitions residues over time with a computer transport model.

Summary/Accomplishments (Outputs/Outcomes):

Past disposal practices of munitions production facilities have resulted in contamination of terrestrial and aquatic ecosystems. Efforts to date have documented the extent of contamination and estimated potential migration routes. To predict the fate and transport of munitions in soils, an accurate description of the adsorption-desorption process is critical.

Investigators hypothesize that munitions residues residing in soils for extended periods may be more tightly bound into a soil organic fraction and that this bound fraction may be more important in predicting the long-term fate and transport of munitions residues. The proposed research will elucidate the transformations, mechanisms, and reversibility of munitions residues in soils with traditional sorption experiments and diffuse reflectance (FTIR) spectroscopy. The validity of using transport equations that assume instantaneous equilibrium, isotherm linearity, and adsorption-desorption singularity in field contaminated soils will also be tested. The proposed research will characterize the sorption of munitions residues in soil and provide improved predictions on desorption kinetics.

Our primary research objectives focused on the fate and transport of munitions residues in soil and water. Reactions leading to natural detoxification were also studied. Additional research objectives addressed remediating munitions-contaminated soil through abiotic and biotic transformations of TNT and RDX in contaminated soil and water.

  • Research results indicated that TNT sorption, transport and degradation are concentration dependent (within the 0 to 70 mg TNT L-1 range). Modeling efforts that assumed a linear adsorption isotherm failed to predict TNT transport. We found that the assumptions of linear adsorption and singular adsorption-desorption, commonly used in transport modeling, are invalid for predicting TNT transport in highly contaminated soils. Nonlinear transport codes were successfully used to model observed TNT breakthrough curves obtained in column transport experiments (Comfort et al., 1995).

  • We provide strong evidence for the formation of bound residues of TNT degradates to surface and subsurface soil. Due to the reduced availability, this process provides one possible pathway for practical detoxification of TNT residues (Hundal et al., 1996).

  • In addition to TNT, soils at munitions production facilities are often contaminated with hexahydro1,3,5-trinitro-1,3,5-trianne (RDX). Contamination can be excessive and soils often contain precipitated or solid-phase RDX, resulting in soil solution concentrations at or near saturation. We characterized RDX sorption and availability in surface soils by equilibrating with 14C-labeled RDX (with and without solid-phase RDX) RDX sorption in the surface soil was adequately described by a linear isotherm and no temporal- or concentration-dependent behavior was observed, except at very high RDX concentrations where slight nonlinear sorption occurred. Limited RDX transformation and bound residue formation occurred in Sharpsburg surface soil and essentially no bound residues formed in subsurface soils. The presence of solid-phase RDX in surface soils also prevented bound residue formation. Most of the sorbed RDX was potentially available for transport, indicating the importance of remediating RDX-contaminated soil to protect groundwater quality. Considering the likelihood of RDX transformation and adsorption in subsoils is minimal, our research indicates an immediate need to remediate soils containing solid-phase RDX since these soils continuously supply RDX to soil solutions and percolating waters (Singh et al., 1998a)

  • We have established that the chemical (abiotic) treatments of Fenton oxidation and treatment with iron metal (Fe0) have an excellent potential to remediate munitions-contaminated soil and water. Using these two techniques, soils with TNT and RDX contamination in excess of 3000 mg kg-1 were successfully remediated below the remediation goals established for the Nebraska Ordnance Plant (17.2 mg TNT kg-1; 5.8 mg RDX kg-1); (Li et al., 1997; Hundal et al., 1997b).

  • We demonstrated that Fenton oxidation of TNT resulted in complete removal of TNT-NO2 groups and formation of oxalate as the primary C-containing end product. When the reaction was conducted in the dark Fenton oxidation resulted in 1 mol of TNT generating roughly 2 mol of oxalate, 3 mol of NO3- and 3 mol of CO2 (40% loss). However, Fenton oxidation can be photocatalyzed to obtain near complete (>90%) mineralization of aqueous TNT. Our experiments demonstrated the Fenton reagent effectively destroyed TNT in aqueous extracts of soil and in soil slurries, and indicates that Fenton oxidation may be a useful remediation treatment for TNT-contaminated water and soil (Li et al., 1997a; 1997b; 1997c). Similar conclusions were drawn from experiments using the Fenton reagent and RDX-contaminated water and soil (Bier, 1997).

  • Developing cost-effective and environmentally benign remediation technologies for explosive-laden soils has become the focus of recent environmental research. We determined the potential of using zero-valent iron (Fe0) to remediate munitions-contaminated soil and water. Recently, we showed that Fe0 effectively transformed TNT and RDX in soil slurries (Hundal et al., 1997). Due to the mechanical equipment required for soil slurry treatment, a desirable alternative would be in situ treatment. We were able to successfully demonstrated this concept by remediating soils containing 30 and 3600 mg RDX kg-1 in static soil microcosms (Singh et al., 1998b).

  • Microbial population in TNT-contaminated soil have been identified and characterized. Numerous experiments on TNT metabolism by a single isolate (P. savastanoi) and consortium were completed and published (Martin et al., 1997). Our experiments provide strong evidence for denitritration of TNT by P. savastanoi and we have determined environmental conditions favoring this degradation pathway. Removal of NH4+ from the medium enhanced TNT denitiration to 2,4-DNT (identified by HPLC and GC-MS). Denitration was further enhanced by addition of NO2- (in the absence of NH4) (Martin et al., 1997).

    The Nebraska Department of Agriculture collaborated with our research group in an evaluation of alternative technologies to remediate and restore pesticide-contaminated soil. We have used similar remediation approaches developed in conjunction with Project 92-24.
    We are currently collaborating with H&H Eco Systems Inc., a Washington-state-based technology development firm, on method development for field-scale treatment of munitions- and pesticide-contaminated soil.

  • Journal Articles on this Report : 10 Displayed | Download in RIS Format

    Other subproject views: All 15 publications 10 publications in selected types All 10 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 Comfort SD, Shea PJ, Hundal LS, Li Z, Woodbury BL, Martin JL, Powers WL. TNT transport and fate in contaminated soil. Journal of Environmental Quality 1995;24(6):1174-1182. R825549C043 (Final)
    not available
    Journal Article Hundal LS, Shea PJ, Comfort SD, Powers WL, Singh J. Long-term TNT sorption and bound residue formation in soil. Journal of Environmental Quality 1997:26(3):896-904. R825549C043 (Final)
    not available
    Journal Article Hundal LS, Singh J, Bier EL, Shea PJ, Comfort SD, Powers WL. Removal of TNT and RDX from water and soil using iron metal. Environmental Pollution 1997;97(1-2):55-67. R825549C043 (Final)
    not available
    Journal Article Li ZM, Comfort SD, Shea PJ. Destruction of 2,4,6-trinitrotoluene by fenton oxidation. Journal of Environmental Quality 1997;26(2):480-487. R825549C043 (Final)
    not available
    Journal Article Li ZM, Shea PJ, Comfort SD. Fenton oxidation of 2,4,6-trinitrotoluene in contaminated soil slurries. Environmental Engineering Science 1997;14(1):55-66. R825549C043 (Final)
    not available
    Journal Article Li ZM, Peterson MM, Comfort SD, Horst GL, Shea PJ, Oh BT. Remediating TNT-contaminated soil by soil washing and Fenton oxidation. Science of the Total Environment 1997;204(2):107-115. R825549C043 (Final)
    not available
    Journal Article Li, Z.M, P.J. Shea, and S.D. Comfort. Nitrotoluene destruction by UV-catalyzed Fenton oxidation. Chemosphere 1998, Volume: 36, Number: 8 (APR), Page: 1849-1865. R825549C043 (Final)
    not available
    Journal Article Martin JL, Comfort SD, Shea PJ, Kokjohn TA, Drijber RA. Denitration of 2,4,6-trinitrotoluene by Pseudomonas savastanoi. Journal of Microbiology 1997;43(5):447-455. R825549C043 (Final)
    not available
    Journal Article Singh J, Comfort SD, Hundal LS, Shea PJ. Long-term RDX sorption and fate in soil. Journal of Environmental Quality 1998;27(3):572-577. R825549C043 (Final)
    not available
    Journal Article Singh J, Comfort SD, Shea PJ. Remediating RDX-contaminated water and soil using zero-valent iron. Journal of Environmental Quality 1998;27(5):1240-1245. R825549C043 (Final)
    not available

    Supplemental Keywords:

    fate and transport, munitions, soil, adsorption, diffuse reflectance spectroscopy., Scientific Discipline, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Geochemistry, Contaminated Sediments, Analytical Chemistry, Fate & Transport, Ecology and Ecosystems, fate and transport, contaminant transport, biodegradation, contaminated sediment, desorption kinetics, bioremediation of soils, chemical kinetics, munitions residues, sorption experiments, contaminant transport models

    Relevant Websites: Exit

    Progress and Final Reports:

    Original Abstract
  • 1993
  • 1994
  • 1995
  • 1996
  • 1997

  • 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