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11 June 2001 AGE-NC Project No. 97-0327 Page 2 of Q 2.2. GROUND WATER SAMPLING Following well purging,ground water levels in the wells achieved a minimum of 80 percent recharge ' prior to sample collection. Ground water samples were collected from the purged wells utilizing new, disposable polyethylene bailers, three 40-m1 EPA-approved VOA vials containing 0.5 m] 18% hydrochloric acid as a sample preservative and one-liter amber bottles without 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 with the well designation, date, time, and sampler's initials. 2.3. LABORATORY ANALYSIS OF GROUND WATER SAMPLES ' 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 5030/8015M and LUFT/EPA 8015B, • 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 16 February 2001; the contaminant impact to ground water was assessed from the laboratory data. 1 3.1. RELATIVE GROUND WATER ELEVATION AND GRADIENT =- - The depths to ground water-in wells MW-1, MW-2 and MW-3 were between 50.58 and'52:07 feet below the tops of the well casings;ground water elevations at the site were calculated to be between 25.07 feet and 25.23 feet below mean sea level. Ground water elevation at the site decreased an average 1.87 feet between the August 2000 and the February 2001 ground water monitoring events. a' Ground water elevations are depicted in Figure 3. Ground water flow direction at the site was inferred to be toward the south at a gradient of 0.002 fl/ft ' Advanced CeoEnvironmental,Inc.