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1 <br /> 10 November 1999 <br /> AGE-NC Project No 98-0450 <br /> Page 2 of 4 <br />' 22 GROUND WATER SAMPLE COLLECTION <br /> The ground water levels in all four wells were allowed to recharged to a mimmum of 80% of the <br />' initial well volume prior to sample collection Giound water samples were collected utilizing <br /> disposable polyethylene bailers and new nylon rope Sufficient ground water sample was collected <br /> from each well to fill three EPA-approved 40-m1 volatile organic analysis (VOA) vials containing <br /> 0 5 ml of hydrochloric acid (1S%) as a sample preservative Care was taken to ensure that visible air <br /> bubbles were not present in the VOAs after filling and capping Ground water sample containers <br />' were labeled with the well designation, date, time and sampler's initials <br /> 23 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 McCampbell Analytical, Inc of Pacheco, California, a Department of Health Service <br /> (DHS)-certified laboratory foi analyses in accordance with the following <br /> • EPA Method 8015 Modified for total petroleum hydrocarbons quantified as gasoline (TPH- <br /> g) <br />' • EPA Method 8020 for volatile aromatics (benzene, toluene ethyl benzene and xylene <br /> BTEX) <br /> • EPA Method 8260 Modified for volatile organic compounds (VOCs) di-isopropyl ether <br />' (DIPE) ethyl tert butyl ether (ETBE) in ethy I-tertiary butyl ether (MTBE), tert amyl methyl <br /> ether (TAME) and tertiary butanol (TBA), respectively <br /> 30 FINDINGS <br />' Ground water elevations and flow direction «eie determined from field measurements h ydiocarbon <br />' impact on ground water was deterinined by laboratory analysis <br />' 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIEN r ` <br /> Fhe depths to ground water from the ground water monitoring wells were measured at 44 03 to 44 75 <br />' feet below the tops of the well casings Over the last quartet ground water elevation has decreased <br /> an average 1 96 feet at the site The ground water elevation data for the well network during the <br /> latest ground water monitoring event is depicted in Figure 3 <br /> Aduurecdc(-ormrronmental, Inc <br />