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' • 10 September 2002 <br /> AGE-NC Project No 95-0142 <br />' Page 2 of 4 <br />' 2 2 GROUND WATER SAMPLE COLLECTION <br /> After allowing the monitoring wells to achieve a minimum of 80%recovery of the pre-purge water <br /> volume,water samples were collected from each well using the dedicated polyethylene bailers The <br />' water was then transferred into EPA-approved 40-milliliter (ml) VOA vials containing 0 5 ml <br /> hydrochloric acid (18%) as,a sample preservative The vials were labeled and placed in a chilled <br /> t container for subsequent transport under chain-of-custody to McCampbell Analytical, Inc (MAI), <br /> a State of California Department of Health Services (DHS) certified laboratory Ground water <br /> samples were analyzed for the following <br /> - Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 8015 Modified, <br /> - Benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary-butyl ether <br /> (MTBE) in accordance with EPA Method 8020, and <br /> - The oxygenated fuel additives di-isopropyl ether(DIPE), ethyl tertiary-butyl ether (ETBE), <br /> MTBE, tertiary-amyl methyl ether(TAME) and tertiary butanol (TBA), methanol, ethanol, <br /> ethylene dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA <br />' Method 8260, respectively <br />' 3.0. FINDINGS <br /> Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 28 January 2002, the contaminant impact to ground water was quantified by the ground water <br /> laboratory data <br /> 3 1 GROUND WATER GRADIENT AND DIRECTION <br />' n water at the site ranged from 26 80 feet to 27 98 feet below the tops of the well <br /> Depth to ground g <br /> casings The ground water elevation in the wells ranged from 14 55 feet (MW-6) to 15 31 feet <br />' (MW-2)below mean sea level(MSL) The average groundwater elevation decreased approximately <br /> 0 55 feet since the previous monitoring event The elevation and ground water depth data is depicted <br /> ' in Table 1 <br /> During the June 2002 monitoring event, ground water flow direction in the shallow ground water <br /> ' table (vapor wells) was toward the northwest with an average hydraulic gradient of 0 01 feet/feet, <br /> ground water flow direction in the intermediate monitored water zone (wells MW-1, MW-2 and <br /> MW-3 ) was toward the northeast with an average hydraulic gradient of 0 006 feet/feet, Ground <br /> 1 , <br /> 1 <br />