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e:\P-jests\5092\g#mvj*p ' were submitted for laboratory analysis. These samples were selected to demonstrate hydrocarbon distribution in the soil below 50 feet. The samples were analyzed for Total Petroleum Hydrocarbons as gasoline (TPHG) and diesel (TPHD), using EPA method 8015 and the appropriate extraction, and for Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) using EPA method 8020. Table 1 - Sod and dater Analytical Results of Well UST-1 presents the analytical results. These analyses show TPHG levels ranging from 480 parts per million (ppm) at 50 feet to nondetectable (<1 ppm) at 85 feet. BTEX levels in the soil samples ranged from 25,000 parts per billion (ppb) at 50 feet to nondetectable (<2.5 ppb) at 85 feet. A ground-water sample was obtained from the well with a stainless steel bailer after purging approximately five casing volumes of water with a submersible pump to assure a sample representative of the aquifer. This sample contained 0.33 mg/L TPHG, 0.80 mg/L TPHD, and BTEX levels ranging from 0.7 to 4.5 ug/L. The sample was also analyzed for soluble lead using EPA method 7421. No lead was detected in the ground water sample. The Benzene concentraton of 4.5 ppb is the only BTEX component which exceeds California regulatory thresholds (1 ppb for Benzene) Laboratory reports orts and chain of custody documents for the soil and ground-water samples , are contained in Appendix B. 3.0 CONCLUSIONS The ground water beneath the site contains detectable levels of hydrocarbons which have probably migrated from the soil above. Only the Benzene concentration of 4.5 ppb exceeds California regulatory thresholds for ground water The lateral and vertical extent of hydrocarbons in the soil was estimated during the May 1990 investigation. The extent of the hydrocarbon plume in the ground water has not been established, although it is probably not very extensive in view of the low levels of hydrocarbons found in this well. 3