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14 August 2002 . <br /> . AGE-NC Project No. 98-0440 <br /> .. Page 2 of 4 <br /> '2.2. COLLECTION 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 /> I was transferred into one 1-liter amber bottle without sample preservative and into three 40-m1 VOA <br /> vials containing 0.5 ml 18%hydrochloric acid as a'sample'preservative.After collection,the samples <br /> were properly labeled, placed in a chilled container and transported under chain-of-custody to <br /> McCampbell Analytical Inc. (MAI)a California Department of Health Services-certified laboratory. <br /> IEach sample was analyzed for: <br /> Total petroleum hydrocarbons quantified as gasoline' and diesel (TPH=g and TPH-d, <br /> respectively) by EPA Methods 8015M/5030/3550; and <br /> • Benzene,toluene,ethyl benzene and xylene(BTEX)and methyl-tertiary butyl ether(MT$E) <br /> by EPA Method 8020. <br />( • 3.0. FINDINGS <br /> Ground water elevation, flow direction, and gradient were determined from field data collected on <br /> I , 26"June 2002; the contaminant impact to ground water was quantified by the laboratory analytical <br /> data. <br /> . 3.1. GROUND WATER GRADIENT AND.FLOW DIRECTION ; <br />( , 'The elevation of ground water in eachwell was calculated by subtracting the depth to ground water <br /> from the surveyed well casing elevations (Table 1). <br /> Depths to ground water ed from 10.93 feet to 11.65 feet below the well casing tops. Ground <br /> . . p gr ranged <br /> water elevations at the site ranged-from 28.65 .feet above mean sea level (MSL) in well MW3 to <br /> E 29.53 feet above MSL in well MW 1. Ground water elevations at the site increased an average of2.58 <br /> feet between the March 2002 and June 2002 sampling events. Ground water levels were within the <br /> screened intervals of,all the monitoring wells on-site. <br /> . The ground water flow direction-was inferred usingground water elevation data. The ground water <br /> _ <br /> at the site on 26 June 2002 was inferred to,have.been flowing to the north-northwest under an . <br /> Iaverage gradient of 0.009 feet/feet across the area monitored. Figure 4 illustrates the ground water <br /> elevation contours. - <br /> Advanced GeoEnyironmental,Inc. <br />