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mounted drilling ng BK81 with eight inch hollow stem augers to drill the sample bonngs to the 65 foot depth A Western Geo-Engineers geologist working directly under the supervision of California Registered Geologist 43037 acted as health and safety officer, supervised the drilling, performed air monitoring, and obtained the water and soil samples Soil borings SB4, SB5 and SB6 were drilled and sampled to 65 feet below ground surface (BGS) These borings were later destroyed by pressure grout-tremie method under the supervision of Ms Mary Maeys of San Joaquin County Health SB7 was drilled near SB5 to 60-feet BGS This boring was converted into a two inch vapor recovery/spargmg well, see Appendix B -- Soil Boring and Well Construction Logs for details Documentation Sampling During drilling and sampling, a Western Geo-Engineers geologist field screened the drill cuttings, ambient air, and the soil and water samples with a MmiRae PID (photo-ionizing detector) that contains a 10 6 ev bulb Sample depths were based on historic site data and the proximity of the boring to the underground fuel dispensing system SB4, sited five feet north of the underground storage tanks (USTs), was sampled at the 15 foot depth and every five foot interval to 65 feet BGS No sample was obtained at the 60-foot depth due to heaving sands preventing the sampler from obtaining a representative sample SB5, sited between MW2 and MW3 at the eastern property line, was sampled at the 30-foot depth and every five-foot interval to 65 feet BGS No samples were recovered at the 55-foot depth and the 60-foot depth due to heaving sands A sample was recovered from the 61-foot depth SB6, sited 20 feet south of the USTs and 15 feet west of the dispensers, was sampled at the 15 foot depth and starting at the 30 foot depth samples were obtained every five feet to the 65 foot depth No sample was obtained from the 60-foot depth due to heaving sands but a sample was obtained from the 61-foot depth SB7, sited approximately 6 feet north of SB5, was sampled at 35 feet BGS and every five-foot interval to the 60-foot depth No usable sample was obtained at the 55-foot depth due to heaving sands Grab water samples were obtained from SB5, SB6 and SB7 Sample Results Samples that exhibited the highest PID response and samples that bracketed the highest PID response were preserved and Chain of Custody (COC) delivered to American Environmental Network (DOHS Certification 1172) for analysis using EPA Method 8020 — Gasoline Range Hydrocarbons (TPHg), Benzene, Toluene, Ethylbenzene, Xylene (BTEX) and Methyl tertiary-Butyl Ether(MTBE) All soil samples were below laboratory lower detection limits for Benzene, Toluene and MTBE All grab water samples were below laboratory lower detection limits for MTBE A graphic comparison was made between the samples obtained from original borings in 1988 to the samples obtained in June of 1997 verification borings and are presented in Appendix C and Laboratory reports in Appendix E 5