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1 � 3 <br /> 1 1 i <br /> • 20 March 2001 <br /> AGE-NC Project'No 96-0235 <br /> IPage 2 of 5 <br /> s , <br /> 22 COLLECTION OF GROUND WATER SAMPLES, <br /> Water,samples were'collected from each purged well using new disposable plastic bailers Each <br />' water sample was transferred into 40-m1 VOA vials pontainmg 0 5 ml 18% hydrochloric acid as a <br /> sample preservative and into 1-liter amber bottles without preservative After collection, the samples <br /> were properly labeled, placed In a chilled container and transported under chain-of-custody to W <br />' McCampbell Analytical, Inc (MAI), a State,of California Department of Health Services (DHS)- <br /> certified analytical laboratory, and were analyzed for <br />' Total petroleum hydrocarbons-quantified as gasoline (TPH-g) and as diesel (TPH-d) in <br /> 1 accordance with EPA Methods 5030/8015 and 355018015, respectively, <br /> Volatile aromatic hydrocarbons - benzene, toluene, ethylbenzene and total xylenes (BTEX) <br /> and methyl tertiary-butyl ether (MTBE) in accordance with EPA Method 60218020, and,for <br />' Fuel oxygenates - di-isopropyl ether (DIPS), ethyl tertiary-butyl ether (ETBE), MTBE, <br /> tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), methanol, ethanol, ethylene <br /> chbrormde(EDB) and 1',2-d_ichloroethane (1,2-DCA) in accordance with EPA Method 8260 <br />' . Modified <br /> r <br />' 3.0. FINDINGS' <br />' Ground,water elevation and flow direction were inferred from field data, hydrocarbon-impact to 2 <br /> ground water was quantified by laborato6 analysis of the groundwater samples Field observations, <br /> results of laboratory analysis of groundwater samples and a discussion of data collected during field ' <br /> work follows <br /> i <br /> I <br />�i 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> The casmg_elevation`ofeach'well was previously surveyed relative to a City of Stockton bench markt <br />' The elevation of groundwater in each well was calculated by subtracting the depth to ground water <br /> from the surveyed casing elevations`(Table 1) Depths to ground water ranged from 16 28 feet to <br /> -18 99 feet below the tops of the well casings Ground water elevations at the site ranged from—11 09 <br /> 1i n i ' <br /> feet in MW-4 to —12 74 feet mean sea level (MSL) in MW-2 Ground water elevation increased an <br /> average of 1 86 feet in the wells f <br />' To infer ground water flow direction, the ground water elevation data,was divided into two sets <br /> based on the well screen intervals Ground water was between 21 05 and 23 20 feet above the <br /> screened intervals'm monitoring wells MW-1, MW-2, MW-6B, MW-8B, MW-9, MW-lI B, MW- <br /> -,4dvanced GcoEnvlronmental,Inc <br /> n <br /> i , ' d <br />