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i 29 December 2004 • AGE-NC Project No 95-0130 Page 3 of 10 2 2 GROUND WATER SAMPLING Ground water samples were collected from wells MW-1, MW-2, MW-3, MW-5 through MW-8, VW-IC,VW-2A and VW-3A utilizing a 3/s-Inch diameter polyethylene tubing and poured directly into the 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 • Totalp etroleum hydrocarbons quantified as gasoline (TPH-g) by EPA Method 8015M, • • Benzene, toluene, ethylbenzene and xylenes (BTEX), 1,2-Dichloroethane (1,2-DCA), ethylene dibromide(EDB), methyl-tertiary butyl ether(MTBE), tertiary butanol (TBA), di- Isopropyl ether(DIPE),ethyl tert butyl ether(ETRE)and tert amyl methyl ether(TAME)by ' EPA Method 8260B r24 QUARTERLY GROUND WATER MONITORING FINDINGS ' Ground water elevation, flow direction and gradient were determined from field data collected on 30 September 2004 The contaminant impact to ground water was quantified by laboratory analysis of water samples 2 4 1 GROUND WATER ELEVATION AND GRADIENT ' The measured depths to ground water from the purged wells were between 43 42 and 45 47 feet below the top of the well casings Ground water elevations were calculated to be between 27 26 ' (MW-7A)feet and 29 09(MW-3 and MW-7E)feet below mean sea level(MSL) Generally,ground water elevation at the site decreased an average of 168 feet between the May 2004 and September 2004 ground water monitoring events First zone (35 to 55 feet) ground water flow ' direction at the Top Filling Station was Inferred to be towards the northeast at an approximate gradient of 0 006 ft/ft, Second zone(55 to 85 feet bsg)ground water flow direction at the Top Filling ' Advanced GeoEnvironmental,Inc