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Sod Erclk"Imn Rssupa Ropon <br /> r, 909 Hammer Lane 5[oddon Caldorrna <br /> Figures 2 and 3 show the approximate final extent of the excavation, soil sampling <br /> locations and depths, and TPH as gasoline analytical results The complete analytical <br /> results are included in Table 1 <br /> Based on the previous boring results, the final excavation depth was approximately 22 <br /> to 25 feet below grade Figure 3 and Table 1 show that all samples analyzed contained <br /> less than 100 parts-per-million (ppm) TPH as gasoline, except sample S-3 at 22 feet <br /> This area was excavated to 25 feet and sample S-11, collected approximately two feet <br /> from S-3, verified removal of the impacted material Overall, the total of twelve soil <br /> samples collected and analyzed confirm successful removal of affected soil <br /> Analytical results from SB-9 indicated soil from 26 to 31 feet contained TPH as gasoline <br /> concentrations ranging from 180 to 240 ppm Because of equipment limitations, this soil <br /> could not be removed However, assuming this soil extends in a 5-foot radius around the <br /> boring location, an estimated 8 6 pounds (or less than 1 5 gallons) of residual TPH <br /> remains in the soil The 5-foot radius assumption is based on the approximate lateral <br /> extent of TPH in the soil around SB-9 at depths of 21 to 22 feet (Figure 3) The <br /> hydrocarbon mass calculation is shown in Attachment 4 No benzene, the most mobile <br /> of the gasoline constituents, has been detected in any of the recent soil boring and <br /> excavation samples Based on these data, remaining hydrocarbons in the soil do not <br /> appear to threaten the relatively deep groundwater Therefore, Aegis recommends this <br /> site for certified closure by San Joaquin County and the California Regional Water Quality <br /> Board, Central Valley Region <br /> 93 005A RER 3 <br />