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15 March 2000 <br /> AGE-NC Project No 96-0229 <br /> Page 2 of 5 <br /> I2 2 GROUND WATER SAMPLING <br /> Following well purging, ground water levels in monztonng wells MW-1 through MW-10 achieved <br /> a minimum of 80 percent recharge prior to sample collection Ground water samples were collected <br /> from the purged wells utilizing new, disposable polyethylene bailers and three 40-m1 EPA-approved <br /> VOA vials containing 0 5 ml 18%hydrochlonc acid as a 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 /> 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 a California Department of Health Services (DHS)-certified laboratory for analysis <br /> Ifor <br /> Total 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, 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 8260M <br /> 3 0. FINDINGS <br /> IGround water elevation, flow direction and gradient were determined from field data collected on <br /> 20 January 2000, the contaminant impact to ground water was assessed from the laboratory data <br /> 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> During the January 2000 monitoring event, depths to ground water from wells MW-1 through <br /> 11 W_1(1 were rneactiro r1 1A R7 nnrul 252 G7 feet 1�eln.■i the tnnc of ihP Nv,a11 o-µointyc rrrr%,i <br /> water elevations were calculated to be between 16 07 feet and 17 44 feet below mean sea level <br /> Ground water elevation at the site decreased an average 0 38 feet between the October 1999 and the <br /> January 2000 ground water monztonng events The ground water elevation data for MW-I through <br /> MW-10 dunng the January 2000 ground water monitoring event is depicted in Figure 3 <br /> Ground water monitoring data collected in the area of wells MW-1 through MW-10 indicated that <br /> 4dvancedCtoEmironmcnt2t, Inc <br />