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. Former UnocaI Service Station #0187 October 9, 1995 Approximately one-foot of clay was encountered at the base of borings U-4, and approximately three feet of silt was encountered in the base of boring U-7 Groundwater Conditions Prior to groundwater sample collection on July 31, 1995, G-R measured the depth to groundwater in wells U-1 through U-8 and UV-1 at depths ranging from 40 85 to 42.95 feet bgs Floating product was not observed in the wells Groundwater measurements were used to construct a Potentiometric Map (Figure 4) Based on these data, shallow groundwater beneath the subject site appears to flow northeast at a gradient of 0 01 to 003 All seven well wells in the groundwater monitoring network were monitored on August 9, 1995 by MPDS Depths-to-groundwater in these wells ranged from 40 77 to 42 80 feet bgs Floating product was not observed in the wells Based on these data, MPDS concluded that groundwater beneath the subject site flowed to the northeast at a gradient of001 CHEMICAL ANALYTICAL RESULTS A total of 24 soil samples from the soil borings and one sample from the stockpiled drill cuttings were submitted for chemical analysis Soil chemical analyses were performed by Sequoia Analytical of Sacramento, California, a California-certified Hazardous Materials Testing Laboratory (ELAP #1624) Soil chemical analytical data has been summarized in Table 2 Copies of the laboratory reports and chain-of-custody forms are presented in Appendix E Groundwater samples collected by G-R were submitted to the Sequoia Analytical lab in Redwood City, California (ELAP #1210) Groundwater analytical data are summarized in Table 1 Copies of the laboratory report and chain-of-custody form are attached in Appendix E Chemical Analytical Procedures All soil and groundwater samples were analyzed for TPHg and BTEX by Environmental Protection Agency (EPA) Method 50301801518020 Stockpile sample SS-1 was also analyzed for total lead by EPA method 6010 4827 04-3 6