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• Subsurface Investigation Report,Tosco(Former BP) Service StationNo 11192 June 8,2001 1,2-dichloroethane (1,2 DCA) tert-amyl methyl ether (TAME) and ethylene dibromide (EDB) by EPA method 8260 Composite soil sample Comp-1(A,B), from the soil stockpile, was analyzed for TPHg (EPA method 8015), BTEX and MTBE (EPA method 8020) and total lead (EPA method 6010) Copies of the laboratory analytical reports and chain-of-custody records are included in Appendix C 4.0 RESULTS 4.1 Subsurface Conditions Groundwater was encountered during probing at approximately 15 5 to 16 5 feet bgs Soils encountered during this investigation consisted primarily of an overlying layer of clay existing from approximately 6 inches below grade to depths ranging form 3 feet to 11 bgs The clay is underlain by silty sand containing a high percent of fine sand in most of the Geoprobes boring locations this layer was observed to the total explored depth In Geoprobes B-3 and B-4, a layer of well graded sand was encounter beneath the silty sand and it extend to the total explored depth The results of the CPT boring confirm the subsurface conditions observed at the geoprobe locations The silty sand observed at the geoprobe locations was also observed at the CPT boring location from . approximately 13 feet bgs to approximately 27 feet bgs From 27 to approximately 55 feet bgs a layer of clay was encountered This clayey layer was interpreted, by the onboard computer, to have several smaller interbedded layers of silty clay At approximately 55 feet bgs the CPT detected a layer of sandy silt to clayey which continued to the total explored depth of 57 feet bgs At 57 feet bgs the CPT rig could not advance the probe any deeper and the test was terminated While advancing the groundwater sampling tool, the CPT operator, Mr David Fisch, felt a change in lithology at 68 bgs which he interpreted being sand According to Mr Fisch, the sand interval extended to the total depth explored (75 feet bgs) 4.2 Soil Analytical Results All soil samples analyzed were found to have no detectable concentrations for all hydrocarbon constituents analyzed The stockpile sample, Comp-l(A,B), contained a concentration of lead that was acceptable for disposal at Allied Waste's Forward Landfill The analytical results from the soil samples are summarized in Table 2 4.3 Groundwater Analytical Results Groundwater samples B-5, B-6 and B-8 had non-detectable concentrations for all hydrocarbon constituents analyzed Sample B-1 contained ethyl-benzene [0 815 parts per billion (ppb)] total xylenes (3 26 ppb) MTBE (90 ppb) and DIPE (2 8 ppb) Sample B-2 contained 15 ppb of MTBE and non-detectable concentrations for all other chemical constituents tested Samples B-3 and B-7 14024503-1 5