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_ 29 April 2002 <br /> AGE-NC Project No. 99-0628 <br /> Page 2 of 4 <br /> 2.2. COLLECTION OF GROUND WATER SAMPLES <br /> _ Water samples were collected from each purged well using new disposable plastic bailers. Each <br /> water sample was transferred into two 1-liter amber bottles, four 500-m1 plastic container without <br /> sample preservative, three 40-m1 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 Alpha Analytical Laboratories, Inc.,a California Department <br /> of Health Services (DHS)-certified analytical laboratory, for analysis. The samples were analyzed <br /> for the following: <br /> • Total petroleum hydrocarbons quantified as diesel, and motor oil (TPH-d, and TPH-mo, <br /> respectively) in accordance with EPA Method 8015 Modified, <br /> • Benzene, toluene, ethylbenzene and total xylenes (BTEX) in accordance with EPA Method <br /> 8020 Modified, <br /> • CAM 17 Metals - lead, copper, nickel, cadmium, arsenic and chromium by EPA Method <br /> 200, <br /> • Hexavalent chromium by EPA Method 7196, <br /> • pH by EPA Method 150.1, <br /> • Anionic surfactants(methylene blue active substances-MBAS)by EPA Method 425.1, and <br /> • Semi-volatile organic compounds by EPA Method 8270. <br /> The laboratory filtered the water samples collected for metals analysis prior to the analyses. <br /> 3.0. FINDINGS <br /> Ground water elevation, flow direction, and gradient were determined from field data collected on <br /> y 26 March 2002. The contaminant impact to ground waterwas assessed from the laboratory analytical <br /> data. <br /> — 3.1. GROUNDWATER GRADIENT AND FLOW DIRECTION <br /> At the time of the March 2002 sampling event, depths to ground water ranged from 50.36 feet to <br /> 51.81 feet below the tops of the well casings (Table 1). Ground water elevations at the site ranged <br /> between 27.85 feet to 27.87 feet below mean sea level (MSL). During this monitoring event, the <br /> Advanced CeoEnvlronmental. Inc <br />