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06 November 2000 • AGE-NC Project No. 97-0327 ' Page 2 of 4 public access. 2.2. GROUND WATER SAMPLING ' Following well purging, ground water levels in monitoring wells MW-1, MW-2 and MW-3 were allowed to achieve a minimum of 80 percent recharge prior to sample collection. Ground water ' samples were collected from the purged wells utilizing new disposable polyethylene bailers, one 1-liter amber bottle without a preservative and four 40-m1 EPA-approved VOA vials containing 0.5 ml 18%hydrochloric acid as a sample preservative. Care was taken to ensure that visible air bubbles were not present in the vials after filling and capping. Ground water sample containers were labeled 1' with the well designation, date, time, and sampler's initials. 2.3. LABORATORY ANALYSIS OF GROUND WATERAMPL S ES ' Each ground water sample was logged on a chain-of-custody form,placed in a chilled container and transported to a California Department of Health Services (DHS)-certified laboratory for analysis for: • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, respectively) by EPA Method 8015M, • Volatile aromatic compounds - benzene, toluene, ethyl benzene and xylene (BTEX) with methyl-tertiary butyl ether(MTBE) by EPA Method 8020, and ' • Fuel oxygenated compounds - ethylene dibromide (EDB), dichloroethane (1,2 DCA), methanol, ethanol, tertiary butanol (TBA), di-isopropyl ether (DIPE), ethyl tert butyl ether ' (ETBE) and tert amyl methyl ether(TAME), and MTBE by EPA Method 8260 Modified. ' 3.0. FINDINGS Ground water elevation, flow direction and gradient were determined from field data collected on 31 August 2000; the contaminant impact to ground water was assessed from the laboratory data. 3.1. — RELATIVE RELATIVE GROUNDWATER ELEVATION AND GRADIENT -- The depths to ground water in wells MW-1, MW-2 and MW-3 were between 48.62 and 50.32 feet • below the tops of the well casings; ground water elevations at the site were calculated to be between 23.48 feet and 23.48 feet below mean sea level. Ground water elevation at the site decreased an average 3.72 feet between the May 2000 and the August 2000 ground water monitoring events. Ground water elevations are depicted in Figure 3. Advanced GeoEnvironmental,Inc.