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P <br /> 1L 1 ' Y ' I a ..NSI.. R• f sr r — f _..- e�, Z k I, 1 , <br /> I <br /> r 1 I <br /> 22 November 1999 <br /> AGE-NC Project No. 95;0135 <br /> r F µ rl l <br /> Page 2 of 4 <br /> I ; <br /> , <br /> hydrochlonc acid,(18%)as a preservative The sarnples were transported in a chillecontainer,under <br /> d ; <br /> ' Ichain of custody,to Precision Enviro-Tech (PET) of Stockton, a State of California Department of <br /> Health Services(DHS)-certified laboratory,for analytical analysi's The samples were analyzed for <br /> Total petroleum hydrocarbons quantified 'as gasoline (TPH-g) in accordance wrth`EFA 'r <br /> ' Method 8015 Modified, <br /> Volatile aromatics benzene, toluene, ethyl benzene and total,xylene (BTEX), Fuel <br /> o matin co -,pounds including methyl tertiary-butyl ether(MTBE),tertiary-butyl alc6hol <br /> xyg g <br /> (TBA), di-isopropyl ether(RIPE),ethyl tertiary-butyl ether{ETBE}and tertiary-amyl methyl <br /> 3ether (TAME) in accordance with EPA Method 8260 Modified <br /> " 3.0. FINDINGS <br /> Ground water flow direction and gradient were inferred from field data, petroleum hvdrocaibon <br /> impact on ground water was determined by the results of laboratory analysis <br /> 31 GROUND WATER ELEVATION AND GRADIENT <br /> During the September 1999 monitoring event,depths to ground water in wells MW-1 through MW,-3 <br /> w the tops of well casings, ground water elevations <br /> were measured between 24 44 and 25,45 feet belo <br /> were calculated to be between 12 23 feet and 12 65 feet below mean sea level Ground water <br /> i elevation at the`site increased an average 0 66 feet between the November 1998 and September 1999, <br /> groundwater monitoring events, making a consistent trend of increasing ground water elevations <br /> September 1997 The ground water elevation data for MW-lB through MW-3B <br /> at the site since p <br /> during,the September 1999 ground water monitoring event is depicted in Figure 3 ' <br /> Due rto}the low gradient at the site, slight variations m ground water me1 11 asurements ar changes of <br /> recharge/discharge of the local ground water could greatly,modify ground water,clava direction <br /> 3 2 LABORATORY RESULTS OF GROUND€WATER SAMPLES <br /> TPH-g concentrations decreased in,three'6f the six wells and BTEX concentrations also showed s <br /> decrease"in the wells, except for the`concentration of ethyl benzene in well MW-1A Benzene was ' <br /> detected in all water samples from well MW-lA/B and MW 2 <br /> r , f <br /> I <br /> 1I0 <br /> r Advanced CeoEnwonmentat,Inc <br /> li <br />