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EXECUTIVE SUMMARY The objectives of this investigation were to further define the extent of impacted sail and to determine if groundwater had been impacted beneath the site To achieve these objectives, soil and groundwater-grab samples were collected for laboratory analysis from three on-site soil borings Soils observed in the three borings consisted of a massive clay and silt sequence overlying a discontinuous silty fine sand interval of undetermined thickness During drilling, groundwater was first encountered at depths ranging from 14 2 to 15 0 feet below ground surface (bgs) Ground surface is approximately 12 feet below street grade Groundwater does not appear to be confined and recharge was found to be moderately strong Soil and groundwater beneath the site have been impacted by gasoline hydrocarbons In soil, the sample coliected at 15 feet from B-2, near the south end of former UST contained the highest concentrations 400 mg/kg of TPH-as-gasoline, 0 3 mg/kg of benzene, 5 9 mg/kg of toluene, 11 mg/kg of ethylbenzene, 43 mg/kg of xylenes, 0 065 mg/kg of MTBE, and 9 5 mg/kg of total lead In groundwater, the sample collected from B-2 contained the highest concentrations 36,000 micrograms per liter (µg/l) of TPH-as-gasoline, 1,700 µg/I of benzene, 4,600 µg/I of toluene, 1,400 lag/I of ethylbenzene, 5,900 µg/1 of xylenes, and 25 µg/l of MTBE Vertically, the extent of impacted soil is mostly delineated but not completely defined at the total drilling depth of 20 feet bgs Laterally, the extent of impacted sal is defined to the south by B-1 and mostly delineated to the north by B-3 The extent of impacted groundwater at the groundwater table is only defined to the north by B-3 Concentrations of gasoline hydrocarbons in groundwater appear to decline significantly to the south at B-1 Based on the distribution of gasoline hydrocarbons in soil and groundwater, the primary source of the impacts appears to be the former gasoline UST The bulk of the hydrocarbon mass is concentrated in soil and groundwater beneath the south end of former UST ' Based on the results of this investigation, Ramage Environmental recommends that a work plan be prepared, which outlines additional environmental corrective actions to be completed at the site Prior to proceeding with the additional corrective actions, PHS/EHD had requested in their letter dated May 16, 2000, that the interested parties meet to discuss the site information and to prioritize the work relative to five other county sites 3