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' 11 September 2003 AGE-NC Project No 99-0624 ' Page 2 of 5 2 2 GROUND WATER SAMPLING ' Following well purging, ground water levels from each well achieved a minimum of 80 percent recharge prior to sample collection Ground water samples were collected from the purged wells ' utilizing the techniques described above in purging each well Ground water samples were transferred mto 40-m1 EPA-approved 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 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 Cal Tech Environmental Laboratories (CTEL), a California Department of Health ' Services (DHS)-certified laboratory for analysis for • Total petroleum hydrocarbons quantified as gasoline (TPH-g) by EPA Method 8015M, ' • Benzene,toluene,ethyl benzene and xylene(BTEX)and methyl-tertiarybutyl ether (MTBE) by EPA Method 8260M, and ' • Tertiary butanol (TBA), di-isopropyl ether(RIPE), ethyl tert butyl ether (ETBE), tert amyl methyl ether (TAME) and MTBE by EPA Method 8260M ' 3.0. FINDINGS ' Ground water elevation, flow direction and gradient were determined from field data collected on 10 June 2003, the contaminant impact to ground water was quantified from the laboratory data 3 1 GROUND WATER ELEVATION AND GRADIENT ' During the 10 June 2003 monitoring event, depths to ground water in wells MW-1 through MW-4 were measured at between 52 08 and 53 21 feet below the tops of the well casings, ground water ' elevations were calculated to be between 13 71 feet(MW-4)and 13 88 feet(MW-1)below mean sea level (MSL) Ground water elevation at the site increased an average 0 49 feet between the March 2003 and the June 2003 ground water monitoring events(Table 2) The ground water elevation data Ifor MW-1 through MW-4 during the June 2003 ground water monitoring event is depicted and . contoured in Figure 3 ' Advanced GeoEnv=ronmental,Inc.