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Mr Martin Harris April 18, 2001 . Page 5 of 6 20 feet bgs at the site to further investigate the extent of soil and groundwater contamination at the site • Lithology generally consists of well graded sand from the ground surface to approximately 9-15 feet bgs, which is underlain primanly by fine grained silts and clays to a depth of at least 21 feet bgs • No petroleum hydrocarbons or VOCs were detect in soil samples collected from depths of 10 and 20 feet bgs in the perimeter borings (MW2, MW3, MW4) • Field observations (odors, staining, FID readings) indicated that soil in the well closest to the former UST (boring MW1) has been contaminated by gasoline, although evidence of contamination decreased with depth TPHg was detected at low levels only in the sample collected from 5 feet bgs • No TPHG or BTEX was detected in the 4 1 composite soil sample collected from the stockpiled soil Lead was detected at 14 ppm in the composite soil sample • Groundwater was initially encountered at approximately 7 to 9 feet bgs during drilling and stabilized at depths ranging from approximately 6 5-7 5 feet bgs Groundwater apparently . flows west The gradient in January 2001 was 0 0013 • Groundwater analytical results indicate that petroleum hydrocarbon contamination is present in groundwater in the vicinity of the former UST at relatively low levels TPHg and xylenes were detected only in wells MW 1 and MW2, located approximately 15 feet west and 45 feet northwest, respectively, from the former UST Benzene, toluene, and ethylbenzene were detected only in well MW 1 However, MTBE was detected at low levels in all site wells • Dissolved benzene levels in groundwater samples exceeded the primary Maximum Contaminant Level (MCL) of 10 ppb only in well MWl (1 6 ppb benzene), and MTBE exceeded the primary MCL of 13 ppb only in well MW4 (16 ppb MTBE) 5.0 CONCLUSIONS The lateral and vertical extent of soil contamination has been defined Analytical results indicate that soil contamination attenuates rapidly with depth and does not appear to extend deeper than approximately 12-13 feet bgs, based upon subsurface investigation conducted at the site Very low levels of gasoline constituents are present in groundwater beneath the site west (downgradient), northwest (cross-gradient), and southwest (cross-gradient) of the former UST, although the extent of contamination appears to be limned to within approximately 60-80 feet of the former UST No wells could be installed upgradient or within 15 feet of the former UST due to property boundaries and surface obstructions G1DatnlGROUNDZE\TuffBoy\RepottslWELLRPT doe