U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

For more information on Natural Attenuation, please contact:

Linda Fiedler
Technology Assessment Branch

PH: (703) 603-7194 | Email: fiedler.linda@epa.gov

Natural Attenuation

Additional Resources

Arsenic Cycling in Hydrocarbon Plumes: Secondary Effects of Natural Attenuation
Cozzarelli, I.M., M.E. Schreiber, M.L. Erickson, and B.A. Ziegler.
Groundwater 54(1):35-45(2015)

NA relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid-phase ferric iron (Fe(III)). Because As adsorbs to Fe-hydroxides, a potential secondary effect of hydrocarbon NA coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. Anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented at a crude-oil-contaminated aquifer near Bemidji, Minn. Groundwater samples collected at the site annually from 2009 to 2013 showed As concentrations in groundwater in the plume reached 230 µg /L, whereas groundwater outside the plume contained <5 µg /L As. A conceptual model of secondary As release due to hydrocarbon NA can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction.

Bioremediation of Chlorinated Solvents Consortium

The Consortium is one of seven Action Teams of the Remediation Technologies Development Forum (RTDF). It was established in May 1993, when representatives from various companies, universities, EPA, DoD, and DOE met to discuss their mutual interest in developing in situ bioremediation technologies to degrade chlorinated solvents in soils and ground water. The historical information concerning the consortium is available through the RTDF home page.

In 2004, the RTDF - Bioremediation Consortium initiated Phase III of its research activities when it joined forces with a multinational team to launch the In Situ Source Area Bioremediation project (SABRE). This project, which is being conducted in the United Kingdom, is scheduled to be completed in 2008 and has a budget of nearly $6 million, financed by industrial members and the DTI LINK Bioremediation program in the UK. The goal is to demonstrate the efficacy of accelerated anaerobic bioremediation as a treatment alternative for source areas contaminated with chlorinated solvent dense non-aqueous phase liquids (DNAPLs). The SABRE project team comprises: Archon Environmental; British Geological Survey (BGS); Celanese Acetate; Chevron; CL:AIRE; DuPont; ESI; GE; Geosyntec Consultants, Inc.; Golder Associates; Honeywell; ICI; Scientifics; SERDP; Shell; SiREM; Terra Systems, Inc; University of Edinburgh; and University of Sheffield. The Environment Agency (EA) of England and Wales and US EPA are also included. In addition, the University of Birmingham and BGS are conducting a complimentary research project (Streamtube) in the SABRE test cell. The project has completed initial characterization of DNAPL source zones, a laboratory microcosm study, installation of the test cell, and baseline data collection. Column studies are well advanced, and modelling is occurring throughout the project. Biostimulation and bioaugmentation of the test cell occurred in the Spring of 2007.

Adobe PDF LogoCORONA: Confidence in Forecasting of Natural Attenuation as a Risk-Based Groundwater Remediation Strategy
Lerner, D.N., P. Bjerg, J. Datel, A. Gargini, P. Gratwohl, C. Holliger, P. Morgan, T. Ptak, R. Schotting, H. Slenders, and S.F. Thornton. Final report of the EU research project EVK1-2001-00087. University of Sheffield, UK. 32 pp, 2005

The CORONA project hypothesizes that a common pattern of biodegradation activity can be found in most ground-water contaminant plumes. High-resolution field data were used to develop three mathematical models for estimating the length of pollution plumes. The models were built into an easy-to-use spreadsheet called CoronaScreen, which is accompanied by manuals for the software and a guidance document to explain how natural attenuation can be assessed in the field and quantified. These engineering tools were tested by practitioners outside the project before being made available for free download from the project website.

Consideration of Natural Attenuation in Remediating Contaminated Sites
Kabardin, B. and J. Frauenstein (eds.).
Federal Environment Agency of Germany, 42 pp, 2011

This position paper discusses how to consider natural attenuation in the context of practical remediation of contaminated sites in Germany and outlines a systematic approach to decision making.

Adobe PDF LogoDissolved Hydrogen Analyzer: Cost and Performance Report
C. Lebron, et al.
NTIS: ADA451214, 40 pp, 2006

This report describes the demonstration at three DoD sites of a portable dissolved hydrogen analyzer, a novel analytical technology developed by Camp Dresser & McKee, Inc., to help determine natural attenuation potential.

Evaluation of the Role of Dehalococcoides Organisms in the Natural Attenuation of Chlorinated Ethylenes in Ground Water
EPA 600-R-06-029, 2006

This report was produced by the U.S. EPA Office of Research and Development. It is designed for technical staff in the EPA Regions and in state agencies that require information on the contribution of Dehalococcoides bacteria to MNA of chlorinated solvents, and information on the proper application and interpretation of the assays in an evaluation of MNA. This report includes sections on the role of biotransformation in evaluation of MNA of chlorinated solvents, the ecology of microorganisms that transform chlorinated solvents, tools to assay microorganisms that transform chlorinated solvents, the relationship between Dehalococcoides DNA in ground water and rates of natural attenuation at field scale, the relationship between geochemical parameters and the occurrence of Dehalococcoides DNA in ground water, and the relationship Dehalococcoides DNA in ground water and behavior of chlorinated solvents in laboratory treatability studies or microcosm studies done with water from the plume.

Interstate Technology and Regulatory Council (ITRC)

Monitored Natural Attenuation Toolbox (MNAtoolbox)

MNAtoolbox identifies primary attenuation pathways and points out processes that might mitigate against MNA for particular contaminants. Sandia National Laboratory has made the toolbox and a user's guide available on its web site.

Sandia Natural Attenuation Project

The Sandia Natural Attenuation Project is a three year program by Sandia National Laboratories to identify the mechanistic controls on metal and organic attenuation by irreversible sorption in the subsurface. SNAP will provide a scientific basis for risk-based corrective actions by helping identify only those sites where contaminants can be expected to impact the biosphere and where Monitored Natural Attenuation (MNA) is likely to be most effective.

Adobe PDF LogoStandardized Procedures for Use of Nucleic Acid-Based Tools: Recommendations for Groundwater Sampling and Analysis Using qPCR
Lebron, C., P. Dennis, C. Acheson, N. Barros, D. Major, E. Petrovskis, F. Loeffler, K. Ritalahti, C. Yeager, E. Edwards, J. Hatt, and D. Ogles. SERDP Project ER-1561, 12 pp, 2014

SERDP project ER-1561 focused on identifying and minimizing the causes of variability during quantitative real-time polymerase chain reaction (qPCR) enumeration of genes of interest in groundwater, with the goal of developing of the knowledge needed to standardize methods for collecting, preserving, transporting, storing, and processing environmental samples for qPCR analysis. This document summarizes the project conclusions and recommends procedures for using qPCR analyses that will provide data of sufficient accuracy and reproducibility to allow site management decisions regarding bioremediation or MNA. Further details are available in the ER-1561 Final ReportAdobe PDF Logo (Lebron et al. 2014, 220 pages).

Superfund Remedy Report, Fifteenth Edition
EPA 542-R-17-001, 2017

The Superfund Remedy Report (SRR), Fifteenth Edition, was published by the EPA Office of Superfund Remediation and Technology Innovation (OSRTI) in August 2017. The report focuses on Superfund remedial actions selected in fiscal years 2012, 2013 and 2014, and on remedy trends since 1982. The report includes remedies selected in 308 decision documents (Records of Decision [RODs], ROD amendments, and Explanations of Significant Differences with changes to remedy components) signed in this three-year period. The SRR compiles data on overall remedy selection and remedies for source materials (such as soil and sediments), groundwater, surface water and air related to vapor intrusion. The report also analyzes media and contaminants for sites with remedies. The appendices summarize all of the remedy components selected for sources and groundwater in each decision document signed in 2012, 2013, and 2014.

Technology Innovation News Survey

The Technology Innovation News Survey contains market/commercialization information; reports on demonstrations, feasibility studies and research; and other news relevant to the hazardous waste community interested in technology development. This report is updated every two weeks.