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1 <br />' . 30 July 2002 <br /> AGE-NC Project No 99-0624 <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 transferred into 40-m1 EPA-approved VOA vials <br /> containing 0 5 ml 18% hydrochloric acid as a sample preservative Care was taken to ensure that <br /> visible air bubbles were not present in the vials after filling and capping Ground water sample <br />' containers were labeled 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 />' 0 Total petroleum hydrocarbons quantified as gasoline (TPH-g) by EPA Method 5030/8015 <br /> Modified, <br /> • Benzene,toluene,ethyl benzene and xylene(BTEX)and methyl-tertiarybutyl ether (MTBE) <br />' by EPA Method 8020, and <br />' • Tertiary butanol (TBA), di-isopropyl ether(DIPE), ethyl tert butyl ether (ETBE), tert amyl <br /> methyl ether(TAME) and MTBE by EPA Method 8260 Modified <br /> t <br /> 3.0. FINDINGS <br />' Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 10 March 2002, the contaminant impact to ground water was quantified from the laboratory data <br /> 3 1 GROUND WATER ELEVATION AND GRADIENT <br />' During the 10 March 2002 monitoring event,depths to ground water in wells MW-1 through MW-4 <br /> were measured between 49 80 and 50 94 feet below the tops of the well casings, ground water <br />' elevations were calculated to be between 1144 feet(MW-4)and 1160 feet(MW-1)below mean sea <br /> level (MSL) Ground water elevation at the site increased an average 2 94 feet between the <br /> December 2001 and the March 2002 ground water monitoring events (Table 2) The ground water <br />' elevation data for MW-1 through MW-4 during the March 2002 ground water monitoring event is <br /> i <br />' Advanced GeoEnvkronmental,Inc <br /> I <br />