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r ' t <br /> ' 28 April 2006 <br /> C AGE-NC Project No 98-0497 <br /> Page 2 of 4 <br /> ' 22 GROUND WATER SAMPLE COLLECTION <br /> Prior to the collection of ground water samples,the depth to ground water was re-measured in each <br /> ' monitoring well to ensure that a minimum 80% of the initial water volume had recharged Water <br /> samples were collected from each well using the inertia pump and dedicated tubing The water was <br /> transferred into one i-liter amber bottle and three 40-milliliter(ml)volatile organic analysis(VOA) <br /> vials containing 0 5 ml 18% hydrochloric acid solution as a sample preservative After collection, <br /> the samples were labeled and placed in a chilled container for transport under chain of custody to <br /> Cal Tech Environmental Laboratories(CTEL),a California Department of Health Services(DHS)- <br /> certified analytical laboratory in Paramount, California The samples were analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, <br /> ' respectively) in accordance with EPA Method 8015M, and <br /> • Benzene, toluene, ethylbenzene, and total xylenes (BTEX) and the fuel additive methyl <br /> ' [ tertiary-butyl ether (MTBE) by EPA Method 8260B <br /> L <br /> 3.0. FINDINGS <br /> '! Ground water elevation and flow direction were inferred from field data Hydrocarbon-impact to <br /> ground water was assessed by laboratory analysis of the ground water samples <br /> ' 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> { At the time of the February 2006 sampling event, depths to ground water at the site ranged from <br /> 65 55 feet(MW-3)to 66 61 feet(MW-4)below the tops of the well casings Ground water elevation <br /> at the site averaged approximately 41 09 feet below mean sea level (MSL), indicating an average <br />' increase in ground water elevations of 2 84 feet since the last monitoring event in December 2005 <br /> Ground water elevation data is included in Table 1 <br />' ! Ground water flow direction was calculated from the ground water elevation data The ground water <br /> ! was inferred to be flowing south-southwest at an approximate hydraulic gradient of 0 008 ft/ft <br /> Figure 3 illustrates the contoured ground water elevations as measured on 27 February 2006 <br /> 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> The analytical results from the e F ebruary 2006 ground water monitoring event are as follows <br /> I <br />' Advanced GeoEnvironmentai,ine <br /> 1 �_ <br />