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Environmental Health - Toxic Substances

Toxics Program Remediation Activities

Natural Attenuation of Wood Preservatives in Ground Water

Type
  • Natural Attenuation Evaluation
  • Site Characterization
Location Pensacola, Florida
Partners
Technology
  • Monitored Natural Attenuation
  • Source Removal (DNAPL recovery wells and soil excavation)
Contaminants
  • Wood preservatives (creosote and pentachlorophenol [PCP])
  • Dioxins
Description

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.
More Information
Contact Ean Warren, USGS, National Research Program, Menlo Park, CA,
Publications
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.
 
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