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May b, 1992 Az 'WA W—= Unocal Station 2859, Stockton, California Results of Analyses of Soil Samples Soil samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg) using modified Environmental Protection Agency (EPA) Method 8015 and benzene, toluene, • ethylbenzene, and total xylene isomers (BTEX) using EPA Method 8020 Laboratory analyses were performed at RESNA Environmental Laboratories (RESNA Analytical) in Cordova, California (Hazardous Waste Testing Laboratory No E773) Soil results of analyses are summarized in Table 1 0 Results of laboratory analyses indicated residual hydrocarbons were detected in soil samples at intervals from 6 feet to 51 feet below grade Oust above ground water) in boring B-10 Hydrocarbons were not detected in the soil samples analyzed from the other borings In addition soil samples S-56-137 and S-55-138 were submitted to Raney Geotechnical of • West Sacramento, California to evaluate the physical properties of the aquifer Specific gravity results were 2 74 and 2 70 for the respective samples, permeability results were 5 5 X 10-7 and 13 X 10-7 centimeters per second Sieve analyses indicated the aquifer is composed of equal amounts of silt and clay Plots of the sieve analyses are included in the attachments of this report 0* GROUND WATER MONITORING On March 4, 1992, a technician from RESNA visited the site to take water-level measurements, conduct subjective analyses of ground water, and collect groundwater samples from wells MW-4 through MW-7 for laboratory analyses Wells MW-1, MW-2, and MW-3 were dry The technician noted no floating product or sheen in the four wells Cumulative results of subjective analyses are presented in Table 2 Water purged from the wells was stored onsite in properly labeled 17-E steel drums pending the results of laboratory analyses At Unocal's request, drummed water was removed and • disposed of by Armour Petroleum Service and Equipment Corporation of Fairfield, California Results of Analyses of Ground-Water Samples The water samples were analyzed for TPHg using modified EPA Method 8015 and BTEX using EPA Method 602 at RESNA Analytical Cumulative results of water analyses are summarized in Table 3 • 38012-9 38oix-9 3 •