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i <br /> 01 June 2003 <br /> • AGE-NC Project No 98-0452 <br /> Page 2 of 4 <br />' 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Water samples were collected from each monitoring well using new disposable battlers after allowing <br />' the wells to achieve a minimum 80% recovery of the pre-purge water volume Each water sample <br /> was transferred into laboratory-supplied 40-m1 VOA vials containing 0 5 ml 18%hydrochionc acid <br /> as a sample preservative After collection, the samples were properly labeled, placed in a chilled <br />' container and transported under chain-of-custody to Cal Tech Environmental Laboratories (CTEL), <br /> a California Department of Health Services(DHS)-certified analytical laboratory, and analyzed for <br />' • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 8015 Modified, and <br /> 1 <br /> • Benzene, toluene, ethylbenzene and xylenes (BTE&X), and the fuel additives methyl- <br /> tertiary-butyl-ether (MTBE), tertiary butyl alcohol (TBA), di-isopropyl ether(DIPE), ethyl <br /> tertiary butyl ether (ETBE), and tertiary amyl methyl ether (TAME), methanol, ethanol, <br /> 1,2-dibromoethane (EDB) and 1,2-dlchloroethane (1,2-DCA) In accordance with EPA <br /> Method 8260B <br /> 3.0. FINDINGS <br /> Ground water elevation and flow direction were calculated from field data The impact to ground <br /> water was assessed 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 subtracting the depth to ground water <br /> from the surveyed well head elevations(Table 1) Depths to ground water ranged from 4 38 feet to <br /> ' 5 32 feet below the tops of the well casings Ground water elevations at the site ranged from <br /> 1 00 feet(MW-3)to 1 19 feet(MW-2)below mean sea level(MSL) The ground water gradient was <br /> calculated to be approximately 0 0023 feet/feet with a flow direction toward the west-southwest <br /> ' (Figure 3) Average ground water elevation was 1 10 feet below MSL and increased an average of <br /> 0 04 feet between the December 2002 and this monitoring events <br /> 3 2 ANALYTICAL RESULTS OF WATER SAMPLES <br /> lTPH-g and BTE&X constituents were not detected at or above laboratory reporting limits In the four <br /> • ground water samples analyzed <br /> ' Advanced GeoEnvsronmental,Inc <br /> 1 <br />