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28 November 2005 <br /> AGE-NC Project No 99-0657 <br /> Page 2 of 5 <br />' 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Ground water samples were collected from each purged well using the Waterra inertia pump and <br /> dedicated tubing after allowing the wells to achieve a minimum 80%recovery of the pre-purge water <br /> volume Each water sample was transferred into one I-liter amber bottle without sample preservative <br /> and into three 40-milliliter (ml) volatile organic analysis (VOA) vials containing 0 5 ml 18% <br /> hydrochloric acid solution as a sample preservative After collection, the samples were properly <br /> labeled, placed in a chilled container, and transported under chain of custody to Cal Tech <br /> Environmental Laboratories (CTEL), a State of California Department of Health Services (DHS)- <br /> certified analytical laboratory, for analysis The samples were analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) and diesel (TPH-d) in <br /> accordance with EPA Method 8015 Modified, and <br /> • Benzene, toluene, ethyl-benzene, and total xylenes (BTEX) and the fuel additives di- <br /> isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), methyl tertiary-butyl ether <br /> (MTBE), tertiary-amyl methyl ether (TAME), tertiary-butyl alcohol (TBA), <br /> 1,2-dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB) in accordance with EPA <br /> Method 8260B <br /> r3.0. FINDINGS <br /> The ground water elevation, flow direction, and gradient were determined from field data collected <br /> on 08 August 2005, the contaminant impact to ground water was quantified by the laboratory <br /> analytical data <br /> 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> At the time of the August 2005 sampling event, depths to ground water ranged from 37 35 feet <br /> (MW-11) to 40 59 feet (MW-9) below the tops of the well casings Ground water elevation at the <br /> site averaged approximately 5 89 feet above mean sea level(MSL),indicating a decrease in average <br /> ground water elevation of approximately 0 34 feet since the last monitoring event in April 2005 <br /> During this monitoring event,the ground water levels in the wells were at least seven feet below the <br /> tops of the well screens, indicating that the wells are screened properly to yield representative <br /> shallow ground water samples <br /> Ground water flow was inferred to be flowing toward the southwest under a hydraulic gradient of <br /> approximately 0 007 foot/foot (ft/ft) on the northern portion of the site, in the southern portion of <br /> IAdvanced CeoEnvironmental,Inc <br />