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14 January 2004 <br /> AGE-NC Project No. 97-0327 <br />' Page 2 of 5 <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-mi EPA-approved volatile organic analysis (VOA) vials <br />' containing 0.5 ml 18%hydrochloric acid as a sample preservative and 1-liter amber bottles without <br /> sample preservative. Care was taken to ensure that visible air bubbles were not present in the vials <br /> after filling and capping. Ground water sample containers were labeled with the well designation, <br />' 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 5030/8015 and LUFT/8015B; <br />.' • Benzene,toluene,ethylbenzene,xylene(BTEX)and methyl-tertiarybutyl ether(MTBE)by <br /> EPA Method 8020. <br />' Ethylene dibromide (EDB), 1,2-dichtoroethane (1,2-DCA), tertiary butanol (TBA), di- <br /> isopropyl ether (DIPE), ethyl tert butyl ether (ETRE), tert amyl methyl ether(TAME) and <br /> MTBE by EPA Method 5030/8260. <br /> 1 J <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 /> 3.1. GROUND WATER ELEVATION AND GRADIENT <br /> The depths to ground water in wells MW-1 through MW-4 were measured between 60.08 and <br />' 61.51 feet below the tops of well casings; ground water elevations in wells MW-1 through MW-4 <br /> were calculated to be between.34.63 feet (MW-3) and 34.74 feet (MW-4) below mean sea level <br /> (Figure 3). Ground water elevation at the site generally decreased an average 1.73 feet between the <br />' Advanced GeoEnvironmental,Iuc. <br />