Posters
Shawnee A


    P30

ENHANCED BIODEGRADATION OF A MIXTURE OF CHLORINATED VOLATILE ORGANIC COMPOUNDS BY AN INDIGENOUS MICROBIAL COMMUNITY FROM A SUPERFUND SITE

 
L.J.W. Barnes(1), S.R. Daniel (1), and J.B. Warner (2), (1)Department of Chemistry and Geochernistry, Colorado School of Mines, Golden, CO 80401, (2)ERM-West, Inc., 1777 Botelho Drive, Suite 260, Walnut Creek, CA 94596 Vinyl chloride, cis- and trans-1,2- dichloroethylene, and 1,1-dichloroethane, along with their parent compounds, tetrachloroethylene, trichloroethylene, and 1,1,1-trichloroethane, are among the ten halogenated aliphatic compounds most frequently found in our ground water supply throughout the United States. Their presence is of concern because of their known toxicity and suspected, or known, carcinogenicity. Chlorinated aliphatics commonly were used in industry as degreasers and solvents.

The study site, in California's Central Valley, originally was contaminated with tetrachloroethylene, trichloroethylene, and 1,1,1 -trichloroethane approximately 40 years ago. Since then, the parent compounds have been degrading naturally, by abiotic and biotic processes, but degradation has not been rapid enough to keep the plume from spreading. The contaminant plume consists predominantly of a mixture of vinyl chloride, dichloroethane, and the dichloroethylene isomers, whereas the parent compounds now occur only in isolated "hot" spots.

Sand and ground water from the site have been used to set up static microcosms with different amendments to encourage microorganisms from the aquifer to biodegrade a mixture of vinyl chloride, cis- and trans-1,2-dichloroethylene, and 1,1-dichloroethane under simulated aquifer conditions. Amendments were chosen that would not introduce additional toxic substances to the ground water as inducers or yield undesirable degradation by-products. Samples were collected from a variety of locations within, and outside of, the plume. The objective of the study was to investigate how biodegradation rates might vary using indigenous microorganisms acclimated to different concentrations and combinations of the compounds of interest. USEPA methods for sample collection and handling, and for chromatographic analysis, have been followed to ensure data quality.

Key words: biodegradation, mixtures, chlorinated, volatile, organics



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Tuesday, May 20, 1997

Metals Kansa A

Remediation of Munitions Compounds Kansa B

Analytical Methods Kansa C/D

General Topics Kansa B


Wednesday, May 21, 1997

Metals Kansa A

Zero-Valent Metals Kansa A

Remediation Kansa A

Vegetation-based Remediation Kansa B

Partnerships & Innovative Technologies Kansa C/D

Nonaqueous Phase Liquids Kansa C/D


Thursday, May 22, 1997

Biofilms & Barriers Kansa A

Bioremediation Kansa B

Partnerships & Technology Innovations Kansa C/D

Remediation Kansa C/D


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