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1 <br /> Ground water was encountered at these borings locations at <br /> approximately 11 to 12 feet bgs Ground water levels subsequently rose <br /> ' in each borehole to stabilize at approximately 7 feet bgs <br /> As illustrated in the drilling logs in Appendix B, geologic conditions <br /> encountered during drilling at the soil boring location (S2-B2) within <br /> the excavation footprint included, from land surface, the following <br /> • Soil fill to 2 feet bgs, <br /> • Gravel fill from 2 feet to approximately 10 feet bgs, and <br /> • Silty sand from 10 feet to the total depth of 15 feet bgs <br /> Ground water was encountered within the excavation backfill at <br /> approximately 7 feet bgs As noted previously, data collected during <br /> this and previous investigations at the site suggests that the confining <br /> ' bed was breached during excavation activities at Site #2 Accordingly, <br /> ground water levels within the excavation footprint are presumed to <br /> reflect the piezometric surface in the area <br /> Soil Chemistry <br /> Each soil sample was analyzed for TPH (Gasoline) by EPA Method 8015 <br /> Modified and BTEX by EPA Method 8020. In addition, one soil sample <br /> was collected from each tank site and submitted for analyses for pH, <br /> total organic carbon (TOC), and total heterotrophic plate count (HPC) <br />' All soil analyses were performed by Sequoia Analytical Laboratory <br /> (Sequoia), a California-certified laboratory, at their facilities in <br /> Sacramento and Redwood City, California All analyses were <br />' performed according to the published EPA-approved procedures, <br /> including adherence to specified holding times. Laboratory results and <br /> Chain-of-Custody Forms are included in Appendix C These analytical <br />' results are summarized below <br /> Former T n #1. Analytical results for soil samples collected at <br />' Former Tank Site #1 are provided in Table 4-1 and summarized on <br /> Figure 4-3 Of the three borings sampled, TPH as gasoline and BTEX <br /> were only detected in soil samples collected from boring S1-B1, which <br />' is located within the former excavation footprint (Figure 4-3) All of <br /> the samples collected from this soil boring were collected from below <br /> the water table The TPH and BTEX concentrations decreased <br /> significantly with depth TPH concentrations exceeded the cleanup <br /> goal of 100 mg/kg for TPH in only one sample, this sample was <br /> collected from the shallowest interval sampled, at approximately 9 feet <br /> 4-5 <br />