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15 June 2004 <br /> AGE-NC Project No 01-0877 <br />' Page 4 of 7 <br /> 2 7 1 Well Monitoring and Evacuation <br /> On 09 October 2003, the depth to ground water in all four monitoring wells was measured from the <br /> top of each well casing to the nearest 0 01-foot utilizing a Solinst water level meter Ground water <br /> elevation in each well was calculated by subtracting the measured depth to ground water from the <br /> surveyed casing elevation (Table 1) <br />' After water levels were measured, between 6 and 6 50 gallons of water (a minimum of 3 casing; <br /> water volumes per well)were purged from the monitoring wells using a Waterra inertial pump and <br />' dedicated hoses Ground water temperature,pH and conductivity were measured at regular intervals <br /> during purging using an Oakton water analyzer Field sheets and data are included in Appendix E <br /> Purged water was stored on-site in properly labeled, 55-gallon DOT-approved drums <br /> 1 _ <br /> 2 7 2 Collection and Analysis of Ground Water Samples <br /> Water samples were collected from each purged well using dedicated tubing after allowing the wells <br />'• to achieve a minimum 80% recovery of the pre-purge water volume Each water sample was <br /> transferred into the following laboratory supplied containers three 40-m1'VOA vials containing <br /> 0 5 ml 18% hydrochloric acid as a sample preservative and one 1-11ter amber bottle without <br />' preservative After collection, the samples were properly labeled, placed in a chilled container and <br /> transported under chain-of-custody to CTEL, a California DHS-certified analytical laboratory, for <br /> analysis The samples were analyzed for <br /> • TPH-g, TPH-d and TPH-mo in accordance with EPA Method 8015 Modified, <br /> • BTEX, MTBE, TBA, DIPS, ETBE, TAME, 1,2-DCA and EDB in accordance with EPA <br /> Method 8260 <br /> I ' <br />' 3.0. FINDINGS <br />' The soil stratigraphy, ground water elevation, flow direction, and gradient were determined from <br /> field data, the contaminant impact to soil and ground water was quantified by the laboratory <br /> analytical data <br /> r <br /> 31 STRATIGRAPHY <br /> Between surface grade and approximately 12 feet bsg,the soil consisted ofbrown to yellow-brown <br /> . and orange-brown clays, silty clays and clayey silts, with a thin, fine-sand lense at approximately <br /> IAdvanced GeoE nviron mental,inc <br /> I <br />