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i6a 09 May 2005 <br /> AGE-NC Project No. 98-0440 <br /> Page 2 of 4 <br /> 2.2. COLLECTION OF GROUND WATER SAMPLES <br /> ` A water sample was collected from each purged well using a new disposable plastic bailer. To <br /> sample DW5157 and DW5055,a hose bib was opened on the water storage tank and samples were <br /> collected from the tank while the pump was operating to obtain a fresh water sample. All samples <br /> were transferred into one 1-liter amber bottle without sample preservative and into three 40-m1 <br /> volatile organic analysis (VOA) vials containing 0.5 ml 18% hydrochloric acid as a sample <br /> preservative. After collection,the samples were properly labeled,placed in a chilled container and <br /> transported under chain of custody to McCampbell Analytical,Inc. (MAI),a California Department <br /> of Health(DHS)-certified laboratory. Each sample was analyzed for: <br /> • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, <br /> respectively) by EPA Method 8015M; and <br /> �. Benzene,toluene,ethylbenzene and xylene(BTEX)and methyl-tertiary butyl ether(MTBE) <br /> by EPA Method 8021. <br /> 3.0. FINDINGS <br /> Ground water elevation, flow direction, and gradient were determined from field data collected on <br /> 26 March 2005.The hydrocarbon:impact to ground water was quantified by the laboratory analytical <br /> data. <br /> 3.1. GROUND WATER GRADIENT AND FLOW DIRECTION <br /> Depths to ground water ranged from 13.07 feet to 13.90 feet below the well casing tops.Ground water <br /> elevations at the site ranged from 26.00 feet above mean sea level (MSL) in well MW-12 to27.13 <br /> ° feet above MSL in well MW-1. Ground water levels were within the screened intervals of all the <br /> k.. monitoring wells on-site. <br /> The ground water flow direction was inferred using ground water elevation data. The ground water <br /> at the site on 26 March 2005 was inferred to be flowing to the north-northwest under an average <br /> gradient of 0.007 foot/foot away from the former UST area and toward the northwest at an average <br /> gradient of 0.006 foot/foot in the northern portion of the site. Figure 3 illustrates the ground water <br /> 'r elevation contours. <br /> i Advanced GeoEnvironmental,Inc. <br />