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23 March 2005 <br /> . AGE-NC Project No 98-0497 <br /> ' Page 2 of 4 <br /> 2 2 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 a clean, disposable plastic bailer The water was <br /> transferred into one 1-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 methyl tertiary-butyl ether <br /> ' (MTBE) in accordance with EPA Method 8021 <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 GROUNDWATER ELEVATION AND GRADIENT <br />' At the time of the November 2004 sampling event, depths to ground water at the site ranged from <br /> 68 11 feet(MW-5)to 69 22 feet(MW-V below the tops of the well casings Ground water elevation <br /> at the site averaged approximately 43#4 feet below mean sea level (MSL), indicating an average <br />' increase in ground water elevations of 1 02 feet since the last monitoring event in September 2004 <br /> Ground water elevation data is included in Table 1 <br />' Ground water flow direction was calculated from the well elevation data The ground water flow was <br /> inferred to be flowing radially outward from a southeast-trending ground water ridge in the vicinity <br /> of well MW-1,under significant hydraulic gradients ranging from approximately 0 05 foot/foot(ft/ft) <br /> to 0 12 ft/ft Figure 3 illustrates the contoured ground water elevations as measured on 12 November <br /> 2004 <br /> 1 <br /> • <br /> Advanced GeoEanronmenkal,Ioc <br />