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1 5 <br />' 24 June 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 />' 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-tertiary butyl ether(MTBE) <br /> by EPA Method 8020, and <br />' Tertiary butanol (TBA), di-isopropyl ether(RIPE), ethyl tert butyl ether (ETBE), tert amyl <br /> methyl ether (TAME) and MTBE by EPA Method 8260 Modified <br /> 1 <br /> 3.0. FINDINGS <br /> Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 11 December 2 00 1,the contaminant impact to ground water was quantified from the laboratory data <br /> 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> During the 11 December 2001 monitoring event, depths to ground water in wells MW-1 through <br /> MW-4 were measured between 52 73 and 53 85 feet below the tops of the well casings, ground water <br /> elevations were calculated to be between 14 35 feet(MW-4) and 14 54 feet(MW-1)below mean sea <br /> level (MSL) Ground water elevation at the site increased an average 1 59 feet between the <br /> September 2001 and the December 2001 ground water monitoring events (Table 2) The ground <br /> Iwater elevation data for MW-1 through MW-4 during the December 2001 ground water monitoring <br /> Advanced Geo Environmental,Inc <br />