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' 24 October 2003 AGE-NC Project No 95-0142 Page 2 of 4 ' 2 2 GROUND WATER SAMPLE COLLECTION After allowing the monitoring wells to achieve a minimum of 80,%recovery of the pre-purge water ' volume,water samples were collected from each well using the dedicated polyethylene bailers The water was then transferred into EPA-approved 40-milliliter (ml) volatile organic analysis (VOA) vials containing 0 5 ml hydrochloric acid(18%)as a sample preservative The vials were labeled and ' placed in a chilled container for subsequent transport under chain-of-custody to McCampbell Analytical, Inc (MAI), a State of California Department of Health Services (DHS) certified , laboratory Ground water samples were analyzed for the following 1 ,. • Total petroleum hydrocarbons as gasoline (TPH-g)in accordance with EPA Method 8015- Modified, and ' Benzene,toluene,ethylbenzene and total xylenes(BTEX)and the oxygenated fuel additives methyl tertiary-butyl ether (MTBE), di-isopropyl ether (D1PE), ethyl tertiary-butyl ether ' (ETBE),tertiary-amyl methyl ether(TAME)and tertiary butanol(TBA),methanol, ethanol, ethylene dibromide (EDB) and 1,2-dzchloroethane (1,2-DCA) in accordance with EPA Method 8260B, respectively ' 3.0. FINDINGS Ground water elevation, flow direction and gradient were determined from field data collected In September 2003 The contaminant impact to ground water was quantified by the ground water laboratory data 4 A 3 1 GROUND WATER GRADIENT AND DIRECTION ' Depth to ground water at the site ranged between 29 26 feet and 30 23 feet below the tops of the well casings The ground water elevation in the wells ranged from 16 65 feet (1\4W-1) to 17 25 feet (MW-8)below mean sea level(MSL) The average ground water elevation decreased approximately ' 0 86 feet since the previous momtonng event The elevation and ground water depth data is depicted in Table 1 ' During this monitoring event, the general ground water flow direction in the shallow ground water r table(vapor wells)was toward the northeast at an average hydraulic gradient of 0 0035 foot/foot and less The elevation of the ground water table at the site is illustrated on Figure 3 i - ' Advanced GeoEnvtronmental,Inc