Remedial Action Lab Report

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The remedial action objectives (RAO) for the Site presented in the ROD are:
· Groundwater: Prevent human ingestion of, inhalation of, or dermal contact with groundwater that contains concentrations of PCE above 5 µg/L, TCE above 5 µg/L, cis-1,2-DCE above 70 µg/L, and trans-1,2-DCE above 100 µg/L (these concentrations are the maximum contaminant level goals (MCLGs) set by the Clean Water Act (or are Maximum Contaminant levels [MCL] where MCLGs are set at zero)).
· Soil: Prevent human ingestion of, inhalation of, or dermal contact with concentrations of PCE and TCE in groundwater, the source of which is contaminated soil with concentrations of PCE and TCE that exceed 0.027 mg/kg and 0.024 mg/kg respectively. That is, while the exposure route involves groundwater as the medium of concern, the source of the PCE and TCE contamination in question is contaminated
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During March and April 2003, NMED drilled additional soil borings. Laboratory analysis of soil samples collected from these borings did not reveal soil contamination or high concentrations of chlorinated solvents, which would suggest the presence of residual contamination that could affect the groundwater and require remedial action. In addition, the Hot Spot Treatment Source Area Investigation Report (CH2M, 2004) presents the results of soil samples collected in the vicinity of the Wells Fargo Parking Lot. Of 32 samples analyzed, only 1 sample, with a PCE concentration of 0.044 mg/Kg, exceeded the remedial goal. The majority of the remaining samples did not detect PCE or TCE supporting a determination that the SVE remedy component was not required.
In March 2001, the NMED Project Manager calculated COC concentrations in soil that would be protective of groundwater. This was the basis for setting a soil remedial goals of 0.027 mg/Kg for PCE and 0.024 mg/Kg for TCE (NMED, 2001). These values were incorporated into the ROD signed on September 27, 2001 (EPA, 2001).
3.4.2 Remedy Element #2: Hot Spot

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