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1 <br /> 23 October 2000 <br /> AGE-NC Project No 98-0448 <br /> Page 2 of 5 <br />' 2 2 GROUND WATER SAMPLING <br /> Following well purging, ground water levels from each well achieved a minimum of 80 percent <br /> recharge prior to sample collection Ground water samples were collected from the purged wells <br /> utilizing new, disposable polyethylene bailers and four 40-mi EPA-approved VOA vials containing <br /> 0 5 ml 18% hydrochloric acid as a preservative Care was taken to ensure that visible air bubbles <br /> were not present in the vials after filling and capping Ground water sample containers were labeled <br /> with the well designation, date, time, and sampler's initials <br /> 2 3 LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br />' Each ground water sample was logged on a chain-of-custody form, placed in a chilled container and <br /> transported to a California Department of Health Services (DHS)-certified laboratory for analysis <br /> for <br /> ITotal petroleum hydrocarbons quantified as gasoline (TPH-g) by EPA Method 8015M, <br /> • Volatile aromatic compounds - benzene, toluene, ethyl benzene and xylene (BTEX) with <br /> methyl-tertiary butyl ether(MTBE)by EPA Method 8020 <br /> • Fuel oxygenated compounds - tertiary butanol (TBA), di-isopropyl ether(DIPE), ethyl tert <br /> butyl ether(ETBE), tert amyl methyl ether(TAME) and MTBE by EPA Method 8260M <br /> I3.0. FINDINGS <br /> AGE determined ground water flow direction and gradient from the field data collected on 03 <br /> August 2000, the contaminant impact to ground water was assessed from the laboratory data <br />' 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> The depths to ground water in wells MW-2, MW-3, MW-4A, MW-4B, and MW-6 were measured <br /> Ibetween 17 01 and 18 92 feet below the tops of the well casings Ground water elevations at the site <br /> were calculated to be between 7 96 feet and 9 51 feet below mean sea level, ground water elevations <br /> are depicted in Figure 3 Ground water elevation at the site increased an average 0 92 feet between <br /> the September 1999 and August 2000 ground water monitoring events <br /> The general ground water gradient at the site was calculated to be approximately 0 009 ft/fl, or <br /> approximately 47 feet per mile, directed towards the south-southwest(Figure 3) <br /> Advanced GeoEnvtronmental,Inc <br />