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Vv� 1 A S S O C I A T E S I N C 2 Groundwater in the uppermost water bearing zone appears to be confined to semi- confined Groundwater flow beneath the site is generally southeast with a magnitude of 0 12 ft/ft, or approximately 660 ft/nule This large magnitude is possibly due to draw down associated with the active supply well located downgradient ' 3 Petroleum hydrocarbon-affected soils are present primarily in the vadose zone at ' approximately 10 to 37 feet bgs The highest concentrations of TPHg and benzene are present in soil under the fill end of the gasoline UST ' 4 Petroleum hydrocarbons have never been detected in wells MW2 or the supply well Petroleum hydrocarbons have not been detected in well MW 1 since January 28, 1993 ' 5 A potential receptor of the petroleum hydrocarbon plume is the on-site small community well The well, located approximately 70 feet downgradient from the petroleum hydrocarbon impacted soil, services approximately 30 employees of BJJ Company providing drinking water and serving other uses of the facility's operations Although groundwater samples from wells MW1, MW2, and the supply well have not contained detectable concentrations of petroleum hydrocarbons since January 1993, the contamination in soil could eventually reach the groundwater and impact this small community well ' 6.0 REMEDIAL ALTERNATIVES Based on the results of previous investigations, ATC has considered three remedial alternatives to ' eliminate the potential for contaminated soil impacting the supply well Remedial alternatives include excavation of remaining petroleum impacted soil, in-situ vapor extraction, and destroying the existing supply well and installing a replacement well in a location where it will not be 1 threatened by the residual contaminated soil A summary of each alternative is presented below ' 6_1 Soil Excavation Excavation of soil contamination and on-site aeration or off-site disposal to a certified waste ' disposal facility would remove the potential source for groundwater contamination As shown on Figure 2, the above ground structures have impeded the removal of the UST and excavation of the petroleum affected areas and extensive shoring and/or demolition of the structures would be ' required 6_.2 Soil Vapor Extraction ' Soil vapor extraction (SVE) has proven effective in reducing volatile organic compounds (VOCs) and certain semi-volatile compounds Vapor extraction wells in the unsaturated zone capture w 194304\mpotU\c1osum doc 5