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1 <br />' 24 February• ru ry 20 03 <br />' AGE-NC Project No 98-0452 <br /> Page 2 of 4 <br />' 2 2 COLLFCTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Water samples were collected from each monitoring well using new disposable bailers 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%hydrochloric 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 McCambell Analytical,Inc (MAI),a California <br /> Department of Health Services (DHS)-certified analytical laboratory, and analyzed for <br /> • TPH-g In accordance with EPA Method 8015 Modified, <br /> • Benzene,toluene,ethylbenzene and xylenes(BTEX)In accordance with EPA Method 8021, <br /> and <br /> • the fuel additives methyl-tertiary-butyl-ether (MTBE), tertiary butyl alcohol (TBA), di- <br /> isopropyl ether (DIPE), ethyl tertiary butyl ether (ETBE), and tertiary amyl methyl ether <br /> (TAME),methanol, ethanol, 1,2-dlbromoethane(EDB) and 1,2-dichloroethane (1,2-DCA) <br /> in accordance with EPA Method 8260B <br /> 3.0. FINDINGS <br /> Ground water elevation and flow direction were calculated from field data, hydrocarbon-Impact to <br /> Iground 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 35 feet to <br /> 5 42 feet below the tops of the well casings Ground water elevations at the site ranged from <br /> 0 97 feet(MW-3)to 125 feet(MW-2)below mean sea level(MSL) The ground water gradient was <br /> calculated to be approximately 0 0022 ft/ft with a flow direction toward the southwest (Figure 3) <br /> Ground water elevation decreased an average of 0 47 feet between the September 2002 and <br /> December 2002 monitoring events <br /> 32 ANALYTICAL RESULTS OF WATER SAMPLES <br /> ITPH-g and BTEX constituents were not detected at or above laboratory reporting limits In the four <br /> . ground water samples analyzed <br /> Advanced C eoEnviron mental,Inc <br />