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I • Total petroleum hydrocarbons quantified as gasoline, diesel and stoddard solvent (TPH-g, iTPH-d, and TPH-ss, respectively) were detected in various ground water samples at I maximum concentrations of 15,000 micrograms per liter (gg/1), 9,300 gg/l, 930 µg/l and 9,500 gg/l,respectively,these maximum concentrations were all present in the sample from wells near EW-1 Low concentrations of BTEX compounds were detected in only three ground water samples • The vertical and the lateral extent of TPH Stoddard has been defined by sample collected • The aerial extent of the soil contamination in vadose zone is defined DISTRIBUTION OF TPH-G AND BTEX - FORMER UST AREA • A release of petroleum hydrocarbons(TPH-g,TPH-d) and benzene,toluene, ethyl benzene and xylenes (BTEX) compounds occurred from dispenser line releases • Petroleum hydrocarbons were not detected in the soil samples collected from below the former UST area, nor excavation, however the most significant mass of hydrocarbons are Ifound below the UST area proper Available data is suggestive of a release was most severe at the southern most dispenser islands,less at the north dispensers and even less between the dispenser islands Once released TPH/BTEX to the subsurface, the contaminants migrated north under the former UST area then vertical depth of approximately 55 feet bsg near the current water table, where the variation concentration in soil samples suggest a smear zone • between 50 feet and 60 feet bsg At this point the TPH contaminants migrating locally down ' to a depth of 75 feet bsg, where non-detect soil samples were collected at the former UST area Additionally,minor concentrations of 1,2-DCA were detected in soil samples collected at the depths of 65 feet to 85 feet bsg, collected below the former UST area O The highest TPH-g and BTEX impact to soil in the upper vadose zone is present at monitoring well borings through the former UST area The TPH-ghighest impact to soil near ' the water table and below the water table to a depth of 75 feet bsg occurs in the UST area A smear zone of five feet of saturated soil contamination is documented at the wells east of the dispenser area,west under the building,where the smear zone of saturated, impacted-soil ' expands to ten or fifteen feet in thickness The aerial extent of the soil contamination in vadose zone is defined to the west of the former UST area ' 0 TPH-g and BTEX compounds were detected in ground water samples collected directly west of the dispenser island at maximum concentrations of 197,000 µg/1 and 18,000 gg/l (benzene) Relatively significant concentrations of TPH-g and BTEX compounds were ' detected in ground water samples collected directly east of the former dispenser island,in the shallow ground water and towards the west under buildmg at the site ' 0 TPH-g and BTEX compounds were also detected in deeper ground water samples collected from wells within the building on the site, inexplicable increasing or remaining at stable concentrations with depth towards from west of the former UST area ' The vertical and the lateral extent of TPH and BTEX has been defined by sample collected ' Advanced GeoEnvironmental,Inc