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i . 5 1 1 Soil Sampling Soil samples were collected at approximate 5-foot intervals in the borings using a California-modified split spoon sampler containing three clean stainless steel sleeves The sampler and sample sleeves were washed with laboratory soap and rinsed with clean water prior to each sampling event Following sample collection, the open ends of the lower sleeve were covered with plastic end caps and made airtight with duct tape This sleeve was labeled with SEACOR project and sample identification numbers and the date, and placed in iced storage Approximately one-half the contents of the middle sleeve was placed in a sealable plastic bag, after 3 to 4 minutes, the probe of an organic vapor meter (OVM) was inserted into the bag and the meter reading in ppm was recorded on the boring log (Appendix A) The remaining contents of the middle sleeve were used for descriptive purposes, which were also recorded on the log of the borings (Appendix A) Soils encountered in the borings were described and classified using the Unified Soil Classification System (Figure A-1) Contents of the upper sleeve were regarded as sluff material and were added to the drill cuttings Contaminated drill cuttings were placed in Department of Transportation (DOT)-approved 17-H drums and left at the site in a fenced and locked storage yard 5 1 2 Laboratory Analyses and Results Soil samples were selected for laboratory analysis based on OVM readings and proximity to the groundwater surface The samples were listed on a chain of custody record (Appendix B) and . transported directly to the laboratory for analysis Selected samples were analyzed for TPHg using Environmental Protection Agency(EPA)method 8015 (modified), and for BTEX using EPA method 8020 by Matrix Environmental Laboratories, Inc of Rancho Cordova, California, a state-certified environmental laboratory for these analyses The results of the laboratory analyses indicated that contamination is present at 21 feet below ground surface onsite and offsite to the west No soil contamination was detected in the sample collected from B2 north of the site, across Monte Diablo Avenue (Table 3) A sample collected from approximately 31 feet below ground surface in a contaminated soil boring (133) indicated that contamination had not migrated downward into the medium gray silty clay encountered beneath the groundwater-bearing zone Soil samples collected from soil borings B4 and B5 located onsite were found to contain the highest concentrations of TPHg and BTEX (Table 3) SEACOR 014-01-1 par 6