The geology at the site consists of reddish-brown, moderately plastic, sandy clay to a depth of roughly 4.6 meters below ground surface underlain by fractured clayey shale with occasional gypsum layers. The depth to groundwater is 2.4 to 3.1 meters below ground surface. Most groundwater flow and contaminant transport appear to occur through a series of weathered shale fractures located immediately beneath the surficial clay and within a thick gypsum layer approximately 10.7 meters below ground surface.
Targeted Environmental Media:
 Fractured Bedrock
Historical solvent releases of degreasing agents at the site have resulted in a 1,520-meter-long plume of chlorinated solvents.
Major Contaminants and Maximum Concentrations:
- Sulfate (1,717,000 µg/L)
- Trichloroethene (5,650 µg/L)
- 1,2-Dichloroethene (427 µg/L)
- Vinyl chloride (0 µg/L)
- Methane (0 µg/L)
- Acetylene (0 µg/L)
- Endosulfan I (0 µg/L)
- Other (Not Documented)
- Bioremediation (In Situ)
- Reductive Dechlorination (In Situ Bioremediation)
Comments:
Emulsified soybean oil was injected into two wells near a landfill in the plume at Operable Unit 1 of the site. The project was started in November 2001 and was completed in January 2003.
The pilot-scale project was conducted to evaluate the potential for an emulsion of soybean oil to promote reductive dechlorination and abiotic transformation of trichloroethene (TCE) in groundwater.
There was substantial decrease in the concentration of TCE without the substantial increases in cis-1,2-dichloroethene and vinyl chloride that would be expected from biological reductive dechlorination. Although the abiotic byproduct acetylene was not detected at appreciable levels, the loss of TCE and sulfate suggests that transformation at this location was primarily a result of abiotic processes, with the biological component providing a measurable, but minor, contribution.
Degradation of TCE can be stimulated by biological and abiotic process in areas with high levels of sulfate and iron. Injection of a soluble or long-lasting substrate can promote reductive dechlorination of TCE and stimulate reduction of sulfate and iron that can then abiotically react with TCE.
References:
Pilots to Enhance Trichloroethene Reductive Dechlorination and Ferrous Sulfide Abiotic Transformation, Paper K-14, in: V.V. Magar and M.E. Kelly (Eds.), In Situ and On-Site Bioremediation 2003. Proceedings of the Seventh International In Situ and On-Site Bioremediation Symposium (Orlando, Florida). June 2003. ISBN 1-57477-139-6, published by Battelle Press, Columbus, Ohio; http:www.battelle.orgbookstore#
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