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• 26 July 2002 ' AGE-NC Project No. 95-0100 Page 2 of 4 ' 2.2. COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES ' Groundwater samples were collected frommonitoring wells MW-1,MW-2,MW-3,MW-5 and MW- 6 after allowing the wells to achieve a minimum of 80 percent recharge of the initial casing water level; a ground water sample was collected from well MW-4 after allowing the well to achieve a 66 percent recharge after 3 hours. Ground water samples were collected utilizing the dedicated disposable,polyethylene bailers and transferred to three 40-m1 volatile organic analysis (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. The samples were properly labeled, placed in a chilled container and transported under chain-of-custody to McCampbell Analytical, Inc. (MAI), a California Department of Health Services-certified analytical laboratory. ' The ground water samples were analyzed for: • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA Method 8015 Modified; ' • 0 Benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary-butyl ether (MTBE) in accordance with EPA Method 8021 B and .• The oxygenated compounds di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), - ' MTBE, tertiary-amyl methyl ether(TAME) and-tertiary butanol (TBA), methanol, ethanol, ethylene dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B. 1 - ' 3.0. FINDINGS Ground water elevation, flow direction, and gradient were determined from field data collected on ' 17 June 2002, the contaminant impact to ground water was assessed from the laboratory analytical data obtained from samples collected during the June 2002 sampling event. 3.1. GROUND WATER ELEVATION/FLOW DIRECTION AND GRADIENT The-depths to groundwater in�wells'MW_12 througli MW-6 were measured at between 49.74 and 51.07 feet below the tops of the well casings; the ground water elevations were calculated to be ' between 65.16 feet (MW-6) and 65-80 feet (MW-1) above mean sea level (MSL). • Advanced GeoEnvironmental,Inc.