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26 February 2007 <br /> AGE-NC Project No. 97-0327 <br /> Page 2 of 4 <br /> 2.2. GROUND WATER SAMPLING <br /> ` After each well was purged, ground water levels were remeasured to verify the amount of ground <br /> water recharge. Upon achieving at least 80%ground water recharge, samples were collected from <br /> _ wells MW-1 through MW-4 utilizing the techniques described above in purging each well. Ground <br /> water samples were transferred into 40-m1 EPA-approved volatile organic analysis (VOA) vials <br /> without preservative and 1-liter amber bottles without sample preservative.Care was taken to ensure <br /> that visible air bubbles were not present in the vials after filling and capping. Ground water sample <br /> containers were labeled with the well designation, date, time, and sampler's initials. <br /> 2.3. LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br /> Each ground water sample was logged on a chain-of-custody form,placed in a chilled container and <br /> transported to a California Department of Health Services (DHS)-certified laboratory; the ground <br /> water samples were analyzed for: <br /> • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, <br /> respectively)by EPA Method 8015M; <br /> • Benzene, toluene, ethylbenzene, xylene (BTEX), methyl-tertiary butyl ether (MTBE), <br /> Ethylene dibromide (EDB), 1,2-dichloroethane (1,2-DCA), tertiary butanol (TBA), di- <br /> isopropyl ether (DIPE), ethyl tert butyl ether (ETBE), and tert amyl methyl ether(TAME) <br /> by EPA Method 8260B. <br /> 3.0. FINDINGS <br /> Field data was utilized to determine ground water elevation,flow direction and gradient.Petroleum <br /> hydrocarbon-impact to ground water was quantified by laboratory analysis. <br /> r <br /> 3.1. GROUND WATER ELEVATION AND GRADIENT <br /> The depths to ground water in wells MW-1 through MW-4 were measured between 45.10 and <br /> 46.45 feet below the tops of well casings; ground water elevations in wells MW-I through MW-4 <br /> were calculated to be between 19.38 feet (MW-3) and 20.11 feet (MW-4) below mean sea level <br /> (MSL) (Figure 3). Ground water flow direction for the area bound by wells MW-1 through MW-4 <br /> was inferred as toward the southwest at a gradient of approximately 0.006 ft/ft. <br /> Advanced GeoEnvironmental,Inc. <br />