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3.0 INVESTIGATION RESULTS <br /> 3 1 Geology and Hydrogeology <br /> Soils observed in the three soil borings consisted of a massive clay and silt sequence overlying <br /> a discontinuous silty fine sand interval of undetermined thickness The silty fine sand interval <br /> was observed in B-1 and B-2 at the total depths of the borings of approximately 20 feet bgs Soil <br /> boring logs are included in Appendix B <br /> During drilling, groundwater was first encountered at depths ranging from 14 2 to 15 0 feet bgs <br />' Groundwater does not appear to be confined and recharge was found to be moderately strong <br /> 32 Analytical Results <br /> Soil and groundwater beneath the site have been impacted by gasoline hydrocarbons The soil <br /> sample analytical results are summarized in Table 1, the groundwater analytical results are <br /> summarized in Table 2, and the laboratory reports are included as Appendix C <br /> In soil, the highest concentrations of gasoline hydrocarbons were detected in the sample <br /> collected at 15 feet from B-2, near the south end of former UST This soil sample contained 400 <br /> mg/kg of TPH-as-gasoline, 0 3 mg/kg of benzene, 5 9 mg/kg of toluene, 11 mg/kg of <br /> ethylbenzene, 43 mg/kg of xylenes, 0 065 mg/kg of MTBE, and 9 5 mg/kg of total lead The soil <br /> samples collected from 20 feet bgs from B-2 and B-3 also contained detectable concentrations <br /> of TPH-as-gasoline and the BTEX compounds The soil sample collected from 15 feet from B-3 <br /> only contained TPH-as-gasoline at a relatively low concentration of 5 8 mg/kg All four soil <br /> samples collected from B-1 near the piping joint P1 did not contain detectable concentrations of <br /> any of the gasoline constituent compounds analyzed <br /> In groundwater, only the samples collected from B-1 and B-2 contained detectable <br /> concentrations of gasoline hydrocarbons The sample collected from B-2 contained the highest <br /> concentrations 36,000 micrograms per liter (µg/1) of TPH-as-gasoline, 1,700 µg/I of benzene, <br /> 4,600 µg/I of toluene, 1,400 �tg/l of ethylbenzene, 5,900 µg/l of xylenes, and 25 µg/1 of MTBE <br /> The groundwater sample collected from B-1 contained 120 µg/I of TPH-as-gasoline, 24 }tg/l of <br /> 1 benzene, 5 2 µg/I of ethylbenzene, 1 5 µgll of xylenes, and 6 8 µg/I of MTBE The groundwater <br /> sample collected from B-3 did not contain detectable concentrations of any of the gasoline <br /> compounds analyzed <br /> 8 <br />