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I • • 1 I26 May 2004 . AGE-NC Project No 99-0637 ' Page 2 of 4 • Total petroleum hydrocarbons quantified as gasoline (TPH-g) and diesel (TPH-d) in accordance with EPA Method 8015-modified, • Benzene, toluene, ethylbenzene and total xylenes (BTEX) and in accordance with EPA Method 8021, and • Fuel additives including methyl tertiary-butyl ether(MTBE),di-isopropyl ether(D1PE), ethyl ' tertiary-butyl ether (ETBE), tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), ethylene dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B 3.0. FINDINGS Ground water elevation, flow direction, and gradient were determined from field data collected on 18 February 2004 The MTBE-impact to ground water was quantified from the laboratory analysis of the ground water samples 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION At the time of the February 2004 sampling event, depths to ground water ranged from 18 45 feet to 20 20 feet below the tops of the well casings Ground water elevations at the site ranged from 13 90 feet above mean sea level (MSL) in well MW8 to 14 56 feet above MSL in well MW6 (Table 1) During this monitoring event, the ground water levels in the wells were at least eight feet below the tops of the well screens, indicating that the wells are screened properly to yield representative shallow ground water samples Ground water flow was inferred to be flowing toward the north-northwest, away from the former UST area at an average gradient of 0 005 feet/feet Figure 3 illustrates the contoured ground water elevations as measured on 18 February 2004 I3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g, TPH-d, BTEX and the fuel oxygenates, with the exception of MTBE, were not detected in any of the ground water samples MTBE was detected in the ground water samples collected from wells MW1,MW2, MW4, MW5, MW5,MW9 and MW 10 at concentrations ranging from 1 6 µg/1 in well MW2 to 1,900 µg/1 in well • MW5 An Iso-concentration map depicting the approximate distribution of dissolved MTBE is presented in Figure 4 Advanced GevEnvirvnmental,Inc