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8820011ST1 CON Moodward-Clyde Consultants 5.0 RESULTS 5.1 Soil Description As shown on the logs in Appendix A, the native soils encountered below surface grade consist predominantly of interbedded clay and silt with occassional sand to a depth of at least 45 feet below grade, the maximum depth drilled for this investigation. In general , the soils to a depth of between 9 and 14 feet below grade consisted of black to dark brown organic clay underlain by fine- to medium-- or medium- to coarse-grained sand. Interbedded orange, red, and tan silt and clay was then encountered in the samples to a depth of 45 feet. The major exception to these findings occurred in Boring C-8, where silt, sand and fine gravel was encountered from 4 to 5.5 feet and then interbedded silt and clay to a depth of 45 feet. 5.2 Laboratory Soil Analysis Soil samples from borings C-A, C-B, C-C, and C-D were selected by Gettler- Ryan to be chemically analyzed by the I.T. Corporation California State DOHS certified laboratory for benzene, toluene, ethyl benzene, xylenes (BTEX) and low boiling point hydrocarbons (gasoline) using EPA Methods 8015, 8020, and 5030. The three soil samples from Boring C-A were also analyzed for high boiling point hydrocarbons and volatile halocarbons using EPA Methods 8010 and 5080. The chemical results are summarized in Tables 2 and 3. The I.T. Corporation analytical report with chemical test procedures and chain-of-custody documents are provided in Appendix B. BTEX and gasoline were not detected in the soil samples from borings C-A, C-B, and C-C, and high boiling point hydrocarbons and volatile halocarbons were not detected in the soil samples from Boring C-A. However, benzene was detected in the soil samples from Boring C-D at 0.12 ppm from a depth of 19 to 20.5 feet and 0.06 ppm from a depth of 29 to 30.5 feet. 6