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the soil boring logs (Appendix A) Soil samples collected from the geoprobe sampler were sealed with teflon tape and plastic end caps The soil samples were labeled with the appropriate borehole I information, time and date of collection, and placed in cooled storage for subsequent transport to and analysis at a State of California certified analytical laboratory Chain-of-custody procedures were followed at all times Soil samples not submitted for laboratory analysis were used to prepare a continuous log of materials encountered during drilling and described by the SECOR field geologist utilizing the Unified Soil Classification System After sampling, each boring was backfilled to the surface with neat cement and restored to match existing conditions I24 Waste Handling Dunng geoprobe operations, sampling tools, and down hole equipment were steam cleaned prior to use The soil generated during the geoprobe operations is currently stored on-site in a 5-gallon approved container and will be disposed of on-site with approval from the PHS/EHD 3.0 RESULTS 31 Litholoev I The lithology beneath the site as observed during this investigation, consists predominantly of a medium-grained sand from approximately one foot to 15 feet bgs At approximately 15 feet bgs, a sandy clay layer was encountered It is likely that this clay layer has prevented the migration of petroleum hydrocarbons from the unsaturated zone soils to the shallow water bearing zone below 3 2 Soil I Selected soil samples were submitted, under appropriate chain-of-custody, to Excelchem Environmental Labs in Roseville, California for analysis of total petroleum hydrocarbons as gasoline (TPHg), and benzene, toluene, ethylbenzene, and xylenes (BTEX), using U S Environmental Protection Agency (EPA) Methods 8015/8020 Laboratory analytical results reported detectable concentrations of TPHg in 4 of the 9 soil samples analyzed The highest TPHg concentration was 242 parts per million (ppm) in the soil sample collected from GP-2 at 15 feet bgs Benzene and toluene were not detected in any soil samples above the laboratory method detection limits The distribution of soil sample analytical results is illustrated on Figure 3 and summarized in Table 1 ICopies of certified analytical reports and chain-of-custody records are included in Appendix B Additionally, three soil samples collected from GP-3 were submitted to Remediation Technology I Testing Facility in Concord, California for analyses of contaminant utilizing bacteria (CUB), and total heterotrophic bacteria (THB) The soil samples were incubated over a twenty day period to evaluate whether subsurface conditions at the site are favorable for bacteria enumeration Plate count results indicate that a substantial colony of CUB and THB are present for intrinsic or natural bioremediation to occur The analytical results of bacteria enumeration are included in Appendix C and summarized in Table 2 i 1434INV RPT SECOR ]0710.002-01 2 October 9 19% I I