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w' } 22 May 2001 ' AGE-i C Project No 95-0167 Page 9of10 The ground water flow direction was determined by plotting and contouring the ground water elevation data The ground water at the site was determined to be flowing toward well MW-2 from well 1\4W-3 and the UST location at an average gradient of 0 002 fl/ft The ground water was also determined to be flowing toward well MW-2 to the west, from off-site (from well MW-6) at an average gradient of 0 01 ft/ft , however,the flow direction toward the east is the hlstoncal direction ' Figure 5 illustrates the contoured ground water elevations as measured on 15 November 2000 ' 4.0 SUMMARY AND CONCLUSIONS Data collected at the site indicates that • The ground water flow direction in the former UST area during this monitoring event was primarily toward the east at a gradient of 0 002 ft/ft • Hydrocarbon impacted soil was not detected below 30 feet bsg in the soil boring advanced In the area of the former UST system Only low concentrations of BTEX compounds were detected locally at 30 feet bsg, while higher concentrations of TPH-g and BTEX compounds were detected locally in soil at 15 and 20 feet bsg The lateral limits of the hydrocarbon impacted soil at the ground water interface and below is limited to the are of the former UST ' and dispenser locations (soil boring samples) • Relatively high concentrations of TPH-g and BTEX occur in ground water in the area of monitoring wells MW l and MW2, with lower concentrations of BTEX extending approximately 130 feet east MTBE is present in monitoring wells MW1 and MW2 at concentrations as high as 480 4g/l (sample MW-1) ' The lateral extent of hydrocarbon impacted ground water is limited to the north and south by monitoring well samples and grab ground water samples (MW-4 and P4) The lateral extent of hydrocarbon-impacted ground water is also limited by the samples collected from well ' MW-3, however, the most recent ground water sample contained significant concentrations of hydrocarbons,which will require additional ground water sampling The impacted ground water extends to depths of at least 40 feet bsg and covers an estimated area of 100 feet by ' 200 feet The estimated lateral extent of impacted ground water is depicted in Figure 4 • Hydrocarbon impacted ground water is not fully defined vertically in the former UST area, ' however a significant portion of the vertical ground water profile of hydrocarbon _ concentrations has been'documented Lower concentrations of MTBE and BTEX were detected at 45 feet bsg, when compared to concentrations of these compounds detected in the ' shallow ground water well samples Advanced GeoEnvironmental,ine