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3 <br /> y <br /> rti <br /> `';�_-7=Ee14_fornia Department of Health Services test methodology. <br /> The minimum detection level for BTEX in soil samples <br /> analyzed by B.C. Laboratories is 0.02 ppm; for TPHG in soil <br /> + samples, 5.0 ppm. <br /> 3.3 Groun <br /> �l5k <br /> Subsequent to installation and well development, water <br /> f samples were collected from the mcaitoring well MW1 after <br /> purging 104 gallons. This is equivalent to approximately <br /> four well volumes (casing and sand pack). The parameters of <br /> ()y EC, pH and temperature were checked during purging, as well <br /> as before and after sample collection to ensure samples <br /> collected were representative of formation water. Purged <br /> water was stored on site in 55 gallon drums (DOT 17) pending <br /> �. laboratory analysis. Water sample collection, preservation <br /> and transportation under chain of custody was conducted in <br /> accordance with WaterWork's Groundwater Sampling Protocol <br /> (Appendix II). The water samples were analyzed for BTEX, <br /> and TPH as gasoline by EPA 5030/8015/8020. The minimum <br /> detection level for BTEX in water samples analyzed by <br /> Sequoia Analytical is 0.3 ppb; for TPH in water samples, <br /> 30.0 ppb, <br /> s;. <br /> 3,4 Quality Assurance/Quality Control Program <br /> The Quality Assurance and Quality Control (QA/QC) Plan, <br /> Appendix III, outlines the field and laboratory procedures <br /> rte, followed to obtain representative data. The previously <br /> ka referenced monitoring and sampling protocols (Appendix II) <br /> outline additional QA/QC procedures. The field <br /> ,., investigation was conducted under the direct supervision of <br /> s Russell Juncal, California Registered Geologist No. 3864, <br /> and Nara i:. Kataoka, California Registered Civil Engineer <br /> No. 38322, <br /> xy <br /> a 4.0 Subsurface Conditions <br /> 4.1 Field Inspection <br /> f. <br /> The soils encountered during drilling consisted of silts, <br /> poor y graded sands and silty sands to 55.0 feet, the <br /> maxi.'mum depth explored. Hydrocarbon odors were noted in the <br /> y upper., ten foot soil interval. Field inspection did not <br /> record the presence of hydrocarbon vapors or the visual <br /> ti staining of soils typically associated with hydrocarbon <br /> >. contamination below a depth of 10 feet. The PID did not <br /> detect volatile organic vapor concentrations in sample above <br /> -� --background-levels-in-samples--between--l0-and---40--feet-. The' . <br /> _ depth.to ,first groundwater beneath.'the 'site was`recorded.'ht�' <br /> epgroximately" 3,8"°fbeYsw'`gratia. Depth .to water <br /> measurements from MWl for several monitorings are presented <br /> in Table l: <br /> J <br /> 3 <br /> z <br /> f <br />