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i r <br /> •s <br />' 13 February 2003 <br />' AGE-NC Project No ,95-0184 <br /> Page 2 of 5 <br />' 22 COLLECTION OF GROUND WATER SAMPLES <br /> Water sarnples were collected from each monitoi ing and vapor`extraction well using new disposable <br />' bailers after allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume <br /> Each water sample was transferred into laboratory-supplied 40-m1 VOA vials containing 0 5 ml 18% <br /> hydrochloric acid as a sample preservative,the sample from.MW-4 was also transferred into a 1-liter <br />' amber bottle without preservative After collection, the samples were properly labeled, placed in a <br /> chilled container and transported under chain-of-custody to Cal Tech Environmental Laboratories <br /> (CTEL), a California Department of Health Services (DHS)-certified analytical laboratory foi <br />' analysis The samples were analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br />' Method 8015m, <br /> • Benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary-butyl ether <br />' (MTBE) in accordance with EPA Method 8021 and 8260, and <br /> • The fuel oxygenates di-isopropyl ether (DIPS), ethyl tertiary-butyl ether (ETBE), MTBE, <br /> tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), and other volatile organic <br /> compounds (VOCs) by GC/MS (full-scan 8260) <br />' In addition, ground water sample MW-4 was also analyzed for diesel (TPH-d) in accordance with <br /> EPA Method 8015m <br />' 3.0. FINDINGS <br />' Ground water elevation and flow direction were inferrca from field data, hydrocarbon-impact to <br /> ground water was quantified by laboratory analysis of the ground water samples <br /> 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> The elevation of ground water in each well was calculated by subti acting the depth to groundwater <br /> from the surveyed casing elevations (Table 1) Depths to,ground water ranged from 34 26 feet to �. <br /> 34 96 feet below the tops of the well casings, however, ground water levels are as high as <br />' approximately 20 feet above the screened intervals Ground water elevations at the site ranged frons <br /> 2166 feet (VW-2B) to 22 18 feet (VW-50 below mean sea lever (MSL) <br />' The ground water appears to flour generally northward acid-,s much of the site at a gradient or <br /> . approximately 0 009 ftlft (Figure 2), however, in the southe.istern portion of the site the Frifetred <br />' ground water flow direction was caste!ly <br /> Advanced(.eohnvrrorimental,Inc <br /> 1 , <br />