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i 04 October 2000 AGE-NC Project No 97-0290 Page 5 of 9 I3 0. FINDINGS The hydrocarbon impact to soil was quantified by the laboratory data obtained from the soil samples collected The SVE unit typically operated at an average of 85 scfm during the period The mass of TPH-g extracted by the SVE system was calculated to be approximately 717 gallons 3 1 STRATIGRAPHY/HYDROCARBON SOIL-VAPOR CONCENTRATION I Brown, damp, silty sand was encountered at 10, 15 and 20 feet bsg Soil composition vaned from silt, silt with sand to sandy silt at 25 and 45 feet bsg Soil composition varied from silt, silty sand to poorly graded sand at 30, 35, and 40 feet bsg At 50, 55, and 60 feet bsg soil composition varied I from poorly graded sand, silt, to clay Poorly graded sand and silty sand was encountered at 65 feet bsg Based on borings the soil has a relatively high sandy content, making SVE an effective remedial method in the vadose zone Organic vapor was detected in soil samples PID data is Included on the boring logs (Appendix A) . Overall, the previous model of site stratigraphy, as presented in the CAP, was observed during drilling activities, during this phase of work Soil types were encountered at similar depth and were also observed to have a similar shape and hydrocarbon Impact Figures 3 and 4 represented modified cross sections of the TPH-g contours as reported in the CAP and the SVE/IAS well Installed within the site-conceptual model of hydrocarbon-Impacted soil I32 ANALYTICAL RESULTS OF SOIL SAMPLES I A total of 27 soil samples were analyzed for TPH-g, TPH-d, and BTEX compounds by EPA Methods 8020 and 8015 Modified ' TPH-g was detected in 26 of the 27 soil samples analyzed from borings VW2 through VW7 and SW3 through SW9 at concentrations as high as 7,400 milligrams per kilogram (mg/kg) TPH-d was detected In 22 of the 27 soil samples analyzed from the borings, with the exception of V W6, at ' concentrations as high as 2,300 mg/kg BTEX compounds were detected In all the borings at concentrations as high as 26 mg/kg, 180 mg/kg, 110 mg/kg and 690 mg/kg, respectively I MTBE was not detected In any of the soil samples collected from wells VW2 through VW7 or SW3 through SW9 Analytical results of soil samples are summarized on Table 1 IThe laboratory reports (MAI Lab I D No 32576-32602), quality assurance and quality control • (QA/QC) report and chain-of-custody forms are included In Appendix B IAdvanced GeuFnvironmental,Inc I