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13 June 2005 <br /> . AGE-NC Project No. 95-0137 <br /> Page 2 of 4 <br /> 2.2. COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Ground water samples were collected from the purged wells using new disposable plastic bailers <br /> after allowing the wells to achieve a minimum 80% recovery of the pre-purge water volume. Each <br /> sample was transferred into three,40-milliliter(ml)EPA-approved volatile organic analysis(VOA) <br /> vials and into one I-liter amber bottle. Samples were properly labeled, stored in a chilled container, <br /> and transported under chain of custody to Cal Tech Environmental Laboratories(CTEL),a California <br /> Department of Health Services(DHS)-certified laboratory,for analysis.Each sample was analyzed <br /> for: <br /> 1 . T <br /> otal petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, <br /> respectively) in accordance with EPA Method 8015 Modified; and <br /> ' Benzene, toluene, ethylbenzene, and total xylenes (BTEX) and fuel oxygenates methyl <br /> tertiary-butyl ether(MTBE),'tertiary-butyl alcohol (TBA),di-isopropyl ether(DIPE), ethyl <br /> tertiary-butyl ether(ETBE),tertiary-amyl methyl ether(TAME), 1,2-dibromoethane(EDB), <br /> and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B. <br /> 3.0. FINDINGS <br /> ' Ground water elevation, flow direction,and gradient were determined from field data collected on <br /> 19 January 2005; the contaminant impact to ground water was quantified from ground water <br />' laboratory data. <br /> 3.1. GROUND WATER GRADIENT AND FLOW DIRECTION <br /> Depths to ground water during the January 2005 monitoring event ranged from 23.36 feet to <br />' 24.42 feet below the tops of the well casings; the depth to ground water remained stable since the <br /> October 2004 monitoring event. The calculated ground water elevations ranged from 33.41 feet <br /> (MW-4) to 36.51 feet (MW-5). <br /> The ground water flow direction was inferred to be northwest,at a significant ground water gradient <br /> of 0.05 foot/foot (ft/ft) east of well MW-1, but at an essentially flat gradient west of well MW-1 <br /> (Figure 3). <br /> 1 . <br />' Advancer!GeoEnvironmental,Inc. <br /> r <br />