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18 May 2006 <br /> AGE-NC Project No 04-1239 <br /> Page 4 of 7 <br /> 2 2 2 Collection and Analysis of Ground Water Samples <br /> Ground water samples were collected from each well using the Waterra inertia pump and dedicated <br /> tubing after allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume <br /> Each water sample was transferred into three laboratory-supplied,40-milliliter(ml)volatile organic <br /> analysis (VOA) vials containing 0 5 ml 18% hydrochloric acid solution as a sample preservative <br /> I After collection, the samples were properly labeled, placed in a chilled container, and transported <br /> under chain of custody to Cal Tech Environmental Laboratories (CTEL), a State of California <br /> Department of Health Services(DHS)-certified analytical laboratory in Paramount, California The <br /> samples were analyzed for <br /> • TPH-g in accordance with EPA Method 8015M, and <br /> BTEX and the fuel additives MTBE, TBA, DIPE, ETBE, TAME, EDB, and 1,2-DCA in <br /> accordance with EPA Method 8260B <br /> 3.0. FINDINGS <br /> Soil stratigraphy and ground water elevation,flow direction,and gradient were determined from field <br /> data The contaminant impact to soil and ground water was quantified from laboratory analysis <br /> 31 STRATIGRAPHY <br /> In general, clayey silt, silty clay, and clay were encountered from surface grade to 15 feet bsg in <br /> boring MW 12, with sandy silt identified at 20 feet and 25 feet bsg Dark gray to green, very fine-to <br /> medium-grained sand was encountered in boring MW 12 at 30 feet and 40 feet bsg,a soil sample was <br /> not recovered at 35 feet bsg In boring MW 13,advanced adjacent to MW 12,dark gray sandy silt was <br /> identified at the top of the 45-foot sample,with clayey silt and silty clay identified to the total depth <br /> of the boring except for an approximately 6-inch thick lens of silty sand encountered near 55 feet <br /> bsg In boring MW 14,silty clay was encountered from 45 feet to 55 feet bsg,underlain by sandy clay <br /> at 60 feet and 65 feet bsg Boring logs are provided in Appendix B <br />' 32 ANALYTICAL RESULTS OF SOIL SAMPLES <br /> A total of eleven soil samples were analyzed for the constituents listed in Section 2 1 1 , no <br /> Ipetroleum hydrocarbon constituents were detected at or above laboratory detection limits in the soil <br /> • samples analyzed Analytical results of the soil samples are summarized in Table 2 The laboratory <br /> Advanced GcoEnvironmcntal,inc <br />