The soils beneath the site consist of a mixture of sands, silt and clay, with what appears to be a thin, low-permeability silt layer located in the middle of the overburden across most of the Site. This layer is absent near the Creek and may be absent in other areas as a result of filling or construction activities. Contamination was observed above, within, and below this low-permeability layer.
The ground water in the overburden aquifer above the bedrock flows toward Little Elk Creek. Ground water flow within the fractures in the bedrock aquifer also appears to flow toward Little Elk Creek. The groundwater gradient for the bedrock is up.
Targeted Environmental Media:
- Dense Non-aqueous Phase Liquids (DNAPLs)
- Fractured Bedrock
- Light Non-aqueous Phase Liquids (LNAPLs)
The bedrock plume has yet to be defined.
Major Contaminants and Maximum Concentrations:
- Acetone (120,000 µg/L)
- 2-Butanone (MEK) (19,000 µg/L)
- Chlorobenzene (21,000 µg/L)
- 1,1-Dichloroethane (38,000 µg/L)
- 1,2-Dichloroethane (36,000 µg/L)
- Methylene chloride (740,000 µg/L)
- Tetrachloroethene (26,500 µg/L)
- Vinyl chloride (14,000 µg/L)
- Chloroform (2,400 µg/L)
- 1,1,1-Trichloroethane (83,000 µg/L)
No technologies selected.
- Pump and Treat
- Bioremediation (In Situ)
- Reductive Dechlorination (In Situ Bioremediation)
Comments:
Pump and treat using a french drain type system began in 2000. Since operations began in March 2000, the GWTS has removed an estimated 23,000 lbs of VOCs (as of September 2010. The treatment system also intercepts bedrock groundwater discharge.
Chemicals given above are a sampling of the contaminants found at the site. Cleanup goals are containment of plume and cleanup to the extent practicable.
For the purposes of investigation and remediation, the Site was divided into two Operable Units (OUs). OU-1 consists of Soil and Overburden Groundwater and OU-2 consists of Bedrock Groundwater. The ROD for OU-1 was issued in September 2004. Remedial Design for OU-1 began in August 2007 and is currently ongoing.
The ROD for OU-2 bedrock groundwater is expected in mid-2011.
http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0300192
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