• Natural Attenuation Evaluation
• Site Characterization

• U.S. Environmental Protection Agency
• Florida Department of Environmental Regulation (Now Florida Department of Environmental Protection)
• U.S. Army Corps of Engineers
• Stanford University

• Monitored Natural Attenuation
• Source Removal (DNAPL recovery wells and soil excavation)

• Wood preservatives (creosote and pentachlorophenol [PCP])
• Dioxins

Wood preservatives (creosote and pentachlorophenol) were disposed of in two unlined pits at a creosote plant near Pensacola, Florida. The contaminants seeped into an aquifer and created a plume 1,000 feet long. USGS scientists discovered contamination at the site in 1981, and assisted with the characterization of the site prior to remediation. In 1983 the Toxic Substances Hydrology Program initiated a study on the occurrence, transport, and degradation of organic contaminants associated with the water-soluble fraction of the wood preservatives. The study was one of the first to demonstrate the natural attenuation of contaminants under methanogenic conditions. Highlights of the results of the study were:

• Documented evidence that methanogenic microorganisms degraded the water-soluble contaminants in the plume to methane (CH4) and carbon dioxide (CO2). The U.S. Environmental Protection agency used this information as the basis for the selection of monitored natural attenuation as the remediation method for the plume of water-soluble compounds at the site.
• Modeling and microbial studies revealed that the plume size and the populations of microorganisms exhibited little change with time. Thus the plume and the microbial community were at steady state. One possible reason for the lack of growth of the microbial community is that the contaminants in the plume are toxic to the microorganisms, thus limiting their growth.
• Information on the kinetics and pathways of biodegradation and transport of polynuclear aromatic hydrocarbons (PAHs), phenolic, and hetrocyclic compounds in ground water. Up to this point very little was known about the environmental fate of these compounds under methanogenic conditions.

• Creosote Waste in Ground Water, Pensacola, Florida (includes complete project bibliography)
• Pensacola, Florida, A Case Study, Compiled by Dr. J. Barry Maynard, University of Cincinnati, Department of Geology, Summary of USGS publications and data
• SBP Membrane Filtration and Bioremediation, Summary of results from a U.S. Environmental Protection Agency, Superfund Innovative Technology Evaluation (SITE) Program project
• SBP Membrane Filtration Reduces Groundwater Contaminants: Tech Trends, U.S. Environmental Protection Agency EPA/542/N-92/003, No. 9, June 1992, p. 2
• Superfund Site Clean-Up Summaries (American Creosote Works, Pensacola Plant)

Bekins, B.A., Warren, E., and Godsy, E.M., 1998,

A comparison of zero-order, first-order, and Monod biotransformation models: Ground Water, v. 36, no. 2, p. 261-268.

Bekins, B.A., Godsy, E.M., and Warren, E., 1997,

Inhibition of acetoclastic methanogenesis by complex mixtures of hydrocarbons: EOS, Transactions, American Geophysical Union, v. 78, no. 46, p. F289.

Bekins, B.A., Godsy, E.M., and Goerlitz, D.F., 1996,

Modeling steady-state methanogenic degradation of phenols in ground water at Pensacola, Florida, in Morganwalp, D.W., and Aronson, D.A., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Colorado Springs, Colorado, September 20-24, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4015, v. 2, p. 843-849.

Godsy, E.M., Goerlitz, D.F., and Grbic'-Galic', Dunja, 1993,

Methanogenic degradation kinetics of nitrogen and sulfur containing heterocyclic aromatic compounds in aquifer-derived microcosms, in Symposium on bioremediation of hazardous wastes: research, development, and field evaluations: U.S. Environmental Protection Agency, EPA/600/R-93/054, p. 123-128.

Godsy, E.M., Goerlitz, D.F., and Grbic'-Galic', D., 1996,

Pathways of methanogenic biodegradation of creosote-derived aromatic compounds, in Morganwalp, D.W., and Aronson, D.A., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Colorado Springs, Colorado, September 20-24, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4015, v. 2, p. 835-841.

Warren, E., and Godsy, E.M., 1996,

Modeling breakthrough of nitrogen heterocyclic compounds in laboratory columns containing creosote-contaminated aquifer material, in Morganwalp, D.W., and Aronson, D.A., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Colorado Springs, Colorado, September 20-24, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4015, v. 2, p. 851-858.

Bekins, B.A., E.M., G., and Goerlitz, D.F., 1994,

Steady-state methanogenic degradation of phenols in groundwater--Inferences from modeling: Journal of Contaminant Hydrology, v. 14, no. 3-4, p. 279-294.

 

USGS Information on Natural Attenuation

• A Unique Approach to Evaluating Natural Attenuation is Applied Worldwide
• Relying on Nature to Clean Up Contaminated Ground Water
  
• Topical Information on Natural Attenuation, Toxics Program
  
• Listing of Toxics Program Projects Evaluating Natural Attenuation
  
• Listing of Other USGS Projects Evaluating Natural Attenuation