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Mr.Scott Rickman Environmental <br /> 13 June 2007 Resources <br /> rPage 5 Management <br /> L� <br /> bgs and 5.5 feet bgs were compared to.ESLs for shallow soil (< 3 meters <br /> bgs) in which groundwater is a current or potential source of drinking <br /> water. Detected concentrations in soil samples collected at 15 feet bgs <br /> and 20 feet bgs were compared to ESLs for deep soil (> 3 meters bgs) in <br /> which groundwater is a current or potential source of drinking water. <br /> Laboratory reporting limits were below established ESLs for the <br /> constituents analyzed with two exceptions: TPH-d had a laboratory <br /> reporting limit of 120 mg/kg for samples SB-1-1.0 and SB-2-1.0, which is <br /> slightly higher than the ESL established for this compound at 100 mg/kg. <br /> However, the elevated reporting limit is most likely due to the detected <br /> concentrations of TPH-mo in these samples. <br /> Based on the analytical results, samples containing detected <br /> concentrations of TPH-mo did not exceed the ESL set at 1,000 mg/kg for <br /> rthis compound. In addition, soil borings that contained detected <br /> �-+ concentrations of TPH-mo in samples collected at 1 foot bgs had <br /> significantly decreased in concentration, or were non-detect above <br /> laboratory reporting limits in the samples analyzed from 5.5 feet bgs. <br /> The sample collected at 20 feet bgs in boring SB-3 contained a detected <br /> concentration of TPH-mo at 14 mg/kg,which is just above the laboratory <br /> reporting limit of 10 mg/kg for this sample. In addition, the sample <br /> analyzed at 15 feet bgs from boring SB-3 was non detect above laboratory <br /> reporting limits for TPH-mo. <br /> The unidentified hydrocarbon compounds reported.in SB-3 and SB-4 <br /> may reflect the presence of naturally-occurring organic material or old <br /> and weathered diesel or motor oil. Regardless, the detected <br /> concentrations are appreciably lower than the ESL for TPH-d and TPH- <br /> mo,which correspond to the type of hydrocarbons detected. <br /> CONCLUSIONS <br /> No evidence of impacts related to VOCs pesticides, TPH- <br /> 1' � � or P g were <br /> identified in any of the samples collected and analyzed. The analytical <br /> results of soil samples collected during this investigation detected <br /> hydrocarbons within the diesel and motor oil ranges in the presumed <br /> upgradient and downgradient portions of the site, or within the footprint <br /> of.the former wastewater pond. The concentrations of hydrocarbons <br /> L <br />