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3.0 INVESTIGATION RESULTS 31 Geology and Hydrogeology Soils observed in the three sod borings consisted mostly of clay and silt sequences to the total drilling depth of 35 feet bgs This sequence appears to be massive and laterally continuous across the site Soil boring logs are included in Appendix B During drilling, groundwater was first encountered at depths ranging from 23 5 to 26 0 feet bgs Groundwater does not appear to be confined and recharge was found to be moderately strong 32 Analytical Results Based on the results of the laboratory analyses, soil and groundwater beneath the site have been impacted by gasoline and kerosene hydrocarbons MTBE and the other oxygenate ' compounds were not detected in any of the sod or groundwater samples analyzed The sod sample analytical results are summarized in Table 1, the groundwater analytical results are summarized in Table 2, and the laboratory reports are included as Appendix C In sod, the highest concentrations of petroleum hydrocarbons were detected in the samples collected from G-3, near the south end of former UST#2 The soil sample collected at 30 feet from G-3 contained 9,100 mg/kg of TPH-as-gasoline, 1 9 mg/kg of benzene, 2 3 mg/kg of toluene, 170 mg/kg of ethylbenzene, 500 mg/kg of xylenes, and 5,900 mg/kg of TPH-as- ' kerosene The soil samples collected from 30 and 35 feet bgs from G-1 also contained detectable concentrations of TPH-as-gasoline, TPH-as-kerosene, and the BTEX compounds ' The soil samples collected from 10, 20 and 25 feet from G-1 and from 20, 25 and 30 feet from G-2 did not contain detectable concentrations of TPH-as-gasoline, TPH-as-kerosene, or BTEX In groundwater, all three samples contained detectable concentrations of TPH-as-gasoline, TPH-as-kerosene, and BTEX compounds The samples collected from G-1 and G-3 contained the highest concentrations of petroleum hydrocarbons The sample collected from G-1 contained 160,000 micrograms per liter (µg11) of TPH-as-gasoline, 5,100 µg11 of benzene, 190 µg11 of toluene, 2,600 µg11 of ethylbenzene, 2,600 µg11 of xylenes, and 53,000 µg/I of TPH-as- kerosene The sample collected from G-3 contained 50,000µg11 of TPH-as-gasoline, 1,900 µg11 of benzene, 220 µg11 of toluene, 6,400 µg11 of ethylbenzene, 5,700 µg11 of xylenes, and 110,000 ' µg11 of TPH-as-kerosene 8