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i 7 5 Report 402.331-87.4 Analytical Results = A total of 5 soil samples and 2 water samples were selected for } chemical analysis (see Table 1). Three soil samples from boring B1 and 2 soil samples from boring B2 were analyzed for total purgeable hydrocarbons as gasoline (EPA Method 8015), purgeable halocarbons (Ethylene Dibromide) (EPA,Method 810), purgeable aromatics (BTEX) (EPA Method 8020) and Total ! Lead (Inorganic Lab/Wet Chemistry Analysis). r i Total hydrocarbons as gasoline were detected in all three soil samples from boring B1. The highest concentration was 43 ppm at 9.5 feet. The water sample from boring B1 showed a concentration of 110 ppm total hydrocarbons. Soil samples from boring B2 were nondetectable for hydrocarbons as gasoline. The water sample from boring B2 showed a concentration of 190 ppm total hydrocarbons. Soil samples; from both borings, tested for BTEX were nondetectable except for the soil sample at 9.5 feet in boring B2. This sample showed concentrations of 4.8 ppm Benzene., 7.4 ppm Ethyel Benzene, 7.4 ppm Toluene and 12.0 ppm Xylenes. The . water sample from boring BI showed Benzene 31 ,ppm, Ethyel Benzene 21 ppm, Toluene 49 ppm and Xylenes 22 ppm. The water sample from boring B2 showed concentrations of 3.8 ppm Benzene, 6.1 ppm Ethyel Benzene, 23 ppm Toluene and 12 ppm Xylenes. The concentrations of Total Lead in soil samples from borings B1 and B2 ranged from 6.9 ppm to 11.0 ppm. Total Lead in the water sample from boring B1 was 6.6 ppm and less than 1 ppm in boring B2. Ethylene Dibromide (EDB). was nondetectable in all soil and water samples tested from both borings. A copy of the laboratory test results and detection limits for the soil and water samples analyzed are included in Appendix B. Soil samples selected for chemical analysis are .identified at the appropriate depths on the boring logs (see borehole logs, Appendix A). Summary and Conclusions 1. The presence of hydrocarbons in the soil and water samples taken from boring B1 and the from the water sample' in boring B2 (as noted in the field and verified by chemical analyses) suggests that the underground gasoline tank at the Tracy Service Center has leaked. 2. The presence of hydrocarbons in the soil samples from boring B1 (absent in boring B2 soil samples) indicates that leakage probably occurred along the eastern end of the tank and migrated vertically through the vadose zone before encountering the water table (at a depth of approximately 9 feet). 3. The presence of hydrocarbons floating on the ground water in both borings indicates some lateral migration of free product has occurred. Measurements of product thickness from both `borings indicates a thinning of, the product plume from boring B1 to B2. The precise direction of plume migration could not be ascertained from this investigation. 4. Lead was detected in all of the soil and water samples tested. 5. EDB was not detected in any of the soil or water samples tested.