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30 SITE INVESTIGATION RESULTS ' 31 Geology and Hydrogeology In general, soils encountered during the drilling of the single sod boring consisted of interbedded mixtures of clay, silt and fine to medium grained sand Between the base of the former excavation ' at approximately 14 feet bgs and a depth of approximately 30 feet bgs, sods consisted of sands interbedded with silty sand and silt intervals Soil samples observed between 35 feet and 45 feet bgs were silt and clay mixtures with little or no sand Soils in this interval were hard and partially- cemented Between 50 and 75 feet bgs, silty fine sand intervals were observed interbedded with silt and sandy silt soils The soil sample collected at 80 feet bgs consisted of clayey silt with some fine sand Detailed soil descriptions are included in a soil boring log (Appendix C) During drilling, gram saturation with groundwater was first observed in soil sampled at 80 feet bgs Approximately 10 minutes after observing the saturated soil, groundwater appeared to stabilize at approximately 78 5 feet bgs During the purging of the temporary well, groundwater appeared relatively clear and recharge was strong 32 Analytical Results The soil sample collected at 15 feet was the only sample to contain TPH-as-gasoline (1,200 mg/kg), benzene (1 7 mg/kg), and MTBE (0 62 mg/kg) The only sod sample found to be free of gasoline constituent compounds was the sample collected at 80 feet bgs The samples collected at 25, 35, 45, 55, and 65 feet only contained low concentrations of toluene (up to 0 016 mg/kg), ' ethylbenzene (up to 0 011 mg/kg), and xylenes (up to 0 064 mg/kg) None of the soil samples contained DIPE, ETBE, TAME, TBA, or 1,2-DCA Total lead was detected in the three soil samples analyzed at concentrations ranging from 5 9 to 12 mg/kg The soil sample results are summarized in Table 1 The laboratory report is included in Appendix C The groundwater-grab sample contained 130 micrograms per liter (µg/l) of TPH-as-gasoline, 1 9 µg/l of toluene, 1 4 µg/I of ethylbenzene, and 9 5 µg/l of xylenes The sample did not contain detectable concentrations of benzene, 1,2-DCA, or any of the oxygenate compounds analyzed The groundwater sample analytical results are summarized in Table 2 The groundwater sample collected from the on-site water well was found to be free of detectable concentrations of the gasoline constituent compounds analyzed These water well sample analytical results are summarized in Table 3 The laboratory reports are included in Appendix C 1 10