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25 November 1997 <br /> AGE-NC Project No '95-0111 <br /> Page 2 of 4 <br /> and methyl-tert-butyl ether (MTBE), in accordance with EPA 8260 for volatile organics and in <br /> accordance with EPA 8260 modified for fuel additives methyl-tert-butyl ether (MTBE) and other <br /> oxygenated fuel additives, including tertiary butyl alcohol (TBA), di-isopropyl ether (DIPS), ethyl <br /> tertiary butyl ether (ETBE) and tertiary amyl methyl ether (TAME) <br />' 3.0. FINDINGS <br /> 3' 1 GROUND WATER FLOW DIRECTION AND GRADIENT <br /> The relative elevation of ground water in each well was calculated by subtracting the ground water <br /> depth from the surveyed casing elevation The depths to ground water and relative ground water <br /> elevations are tabulated in Table 1 -Relative Ground Water Elevation Data All wells were surveyed <br /> relative to the casing of momtoring well MW-1, which had been assigned an arbitrary casing <br /> elevation of 20 feet <br /> The depth to ground water ranged from 9 83 feet below the well casing (bwc)in MW-1 to 6 51 feet <br />' bwc in MW-4 The relative ground water elevation at the site ranged from 10 68 feet in MW-3 to <br /> 9 21 feet in MW-6 The relative ground water elevation increased an average of 0 02 feet at the site <br /> between June and October 1997 The ground water flow direction at the site was toward the north- <br /> northeast Ground water gradient was approximately 0 0049 ft/ft over the distance from the up <br /> gradient to the down gradient monitoring wells Ground water elevation isocontours are depicted in <br /> Figure 3 - Relative Ground Water Elevation <br />' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was detected in samples collected from monitoring wells MW-1, MW-4 and MW-5 at <br />' concentrations of 330 micrograms per liter(/.cg/l, approximately equivalent to parts per billion ppb), <br /> 100 ppb and 120 ppb, respectively TPH-d was detected in samples from wells MW-1, MW-4 and <br /> MW-5 at concentrations of 130 ppb, 1,400 ppb and 5,800 ppb, respectively Laboratory notations <br />' for the ground water sample collected from wells MW-5 indicated the presence of an immiscible <br /> sheen <br />' Benzene was detected in samples collected from wells MW-1, MW-2, MW-4 and MW-5 at <br /> concentrations as high as 120 ppb, ethyl benzene and xylenes were detected in samples from MW-1 <br /> and MW-2 at concentrations as high as 6 0 ppb Toluene was not detected in any of the ground <br /> water samples <br /> r <br /> Advanced GeoEnvironmental Inc <br />