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m <br /> r <br /> 1 11 u f <br /> 05 June 1998 t <br /> AGE-NC,Project No 96-0232 , <br />' Page 2 of 4 - y r - • 1 f ' <br /> J' <br /> 22 GROUND WATER SAMPLE COLLECTION <br /> The ground water levels in all three site wells were allowed to recover for a minimum of one hour <br /> } a prior to sample collection Ground water samples were collected utilizing disposable polyethylene <br />' bailers and new nylon rope Sufficient ground water sample was collected from each well to fill a <br /> one-liter ,amber bottle and three EPA-approved 40-m1 VOA vials containing 0 5 ml 18% <br /> hydrochloric acid as'a preservative for the samples Care was taken to ensure that visible air bubbles <br /> were not present In the VOAs after filling and capping Ground watLer sample containers were labeled ' <br /> with the well designation, date, time, and sampler's initials <br /> ti + I v <br /> 4 <br /> 23 LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br /> Each groundwater sample was logged on a chain-of-custody form,placed In a chilled container and <br /> transported to a California state-certified laboratory for analysis In accordance'wlth the follow,ng t <br /> • EPA method 8015M for'total petroleum hydrocarbons quantified as gasoline and diesel <br /> (TPH-g'and TPH-d, respectively) <br /> • EPA method 8020 for volatile aromatics (benzene, toluene, ethyl benzene and xylene <br /> BTE&X) with methyl-tertiary butyl ether (MTBE) <br />' • EPA Method 8260 for tertlary'butanol (TBA), di-isopropyl ether (DIPE). ethyl tert butyl <br /> ether,(ETBE) and tert amyl methyl ether (TAME), and to confirm and,quantify,MTBE'If <br /> _detected by EPA Method 8020 v <br /> 1 <br /> 3.0. FINDINGS v <br />' 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> The depths to ground water from all three ground water monitoring wells were measured at 2 79 to <br /> 2 26 feet below the top',of the swells Between July 1996 and February 1998, ground,water elevation n <br /> has increased an average 11 75 feet at the site The ground water elevation data for all three site wells <br /> during the February 1998 ground water monitoring event Is depicted in Figure 3 ; <br /> During the February 1998 monitoring event, ground water was approximately 6 74 feet above the <br /> M -4' <br /> screened Intervals in moriitoring'well WThe screen intervals are"not known `for monitoring } <br /> wells MW-I and MW-2, however, Ibis likely that the screened intervals from these wells are <br /> drowned based on curient ground water elevation u The screened interval from,well MW-4 Is , <br /> Advanced GeoEn%iron mental,Inc ' <br /> 4 <br /> ! 1 <br />