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1 <br /> ' 20 March 2002 <br /> �. AGE-NC Project No 95-0144 <br /> ' Page 4 of 7 <br /> 1 3 1 WELL MONITORING AND EVACUATION <br /> A Solinst water level meter was used to measure the depth to ground water in 14 monitoring wells <br /> 1 at the subject site relative to the tops of the well casings The ground water elevation, flow direction <br /> and hydraulic gradient were determined from these data(Table 1) <br /> ' After depth to water measurements were recorded,the wells to be sampled were purged using new, <br /> disposable bailers Approximately three casing-water volumes of water (approximately 6 to 18 <br /> gallons)were removed from each of the purged wells Temperature,pH and conductivity of purged <br /> water were measured at regular purge-volume intervals using an Oakton water analyzer The <br /> recorded field data and logs are included in Appendix A All purged water was stored in 55-gallon <br /> DOT-approved drums on-site <br /> 3 2 COLLECTION OF GROUND WATER SAMPLES <br /> The depth to water was remeasured immediately following purging each well to gauge the recharge <br /> rate and to assure a minimum of 80 percent recharge prior to sampling although three wells <br /> r• (MW-19A,MW-20B and MW-21 B)were balled dry and were sampled pnor to 80 percent recharge <br /> Water samples were collected from each purged well using new disposable bailers Samples were <br /> transferred Into 40-m1 EPA-approved VOA vials containing 0 5 ml 18% hydrochloric acid as a <br /> ' sample preservative and Into 1-liter amber bottles without preservative The samples were labeled, <br /> stored on ice and transported under chain-of-custody to McCampbell Analytical, Inc (MAI), a <br /> California Department of Health Services(DHS)-certified analytical laboratory Each sample was <br /> analyzed for <br /> ' • TPH-g, TPH-d and TPH-mo in accordance with EPA Methods 5030/8015 and 355018015, <br /> respectively, <br /> • BTEX and methyl tertiary-butyl ether(MTBE) in accordance with EPA Method 80201602, <br /> and <br /> • Fuel oxygenated compounds - tertiary butanol (TBA), di-isopropyl ether(DIPE), ethyl tert <br /> butyl ether (ETBE), tert amyl methyl ether (TAME) and MTBE by EPA Method 8260M <br /> 40. FINDINGS <br /> ' Ground water elevation and flow direction were inferred from field data, hydrocarbon-impact to <br /> ground water was quantified from laboratory analysis of the ground water samples <br /> Advanced GeoEnviron mental,Inc <br />