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7 23 June 1999 ; AGE-NC Project No 95-0121 Page 3 of 5 samples, fuel oxygenated compounds were detected in four ground water samples 3 1 y RELATIVE GROUND WATER ELEVATION AND GRADIENT The depths to ground water from wells MW-1 through MW-9 were measured at between 13 49 and ' 15 45 feet below the tops of the well casings Ground water elevations at the site were calculated to be between 8 11 feet and 8 49 feet below mean sea level, ground water elevations are depicted in Figure,3 Ground water elevation at the site increased an average 1 16 feet between the December ' 1998 and the March 1999 ground water monitoring events, a long term trend of Increasing ground water elevations is Indicated by data obtained at the site since February 1991 When monitoring began,�the general ground water gradient in the area containing wells MWA, MW-2, MW-3 and ' MW-6 was,calculated to be approximately 0 003 ft/ft or approximately 16 feet per mile and directed towards the northeast, ground water gradient in the area containing MW-2, MW4, MW-7 and MW- 8 was calculated to be approximately 0 001 ft/ft or approximately 5 feet per mile and directed ' towards the east-northeast, ground water gradient In the area containing MW-5, MW-6 and MW-9 was calculated to be approximately 0 002 ft/ft or approximately 11 feet per mile and directed towards the north-northeast r , The ground water surface elevation at the site Is approximately 9 feet to 18 feet above the slotted ' screen Intervals in wells MW-1 through MW-9 Therefore these wells are "drowned", and do not yield samples representative of shallow ground water 32 � ' LABORATORY RESULTS OF GROUND WATER SAMPLES Utilizing EPA Method 8015M, TPH-g was detected in water samples collected from wells MW-1 through MW-4 and MW-7 at concentrations ranging between 4,700 micrograms per liter (µg/l) and 54,OOO,ug/1,TPH-d was detected in water samples collected from wells MW-1 through MW-4,MW- ' 7 and MW-8 at concentrations ranging between 170µg/I and 9,900µg/1, respectively However, the laboratory reported that the chromatograms for the samples did not ' have typical diesel ' characteristics Utilizing EPA Method 8020, various,BTEX compounds were detected in water samples collected ' from MW-1 through MW-4 and MW-7 at concentrations ranging as high as 13,000 ,Ug/l (benzene MW-3) MTBE was rdetected In'water samples collected from MW-5 and MW-6 at concentrations, as high as 3 2 µg/1 UtIIIZIng EPA Method 8260, MTBE was detected In water samples collected from wells MWA, MW-2 and MW-5 at concentrations ranging as high as 130 pg/l No other fuel oxygenated " Advanced GeoEmironmental,Inc