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26 June 2002 <br /> i� AGE-NC Project No 95-0144 <br /> ' Page 2 of 5 <br /> accordance with the revised monitoring schedule established at a 03 April 1998 meeting with the <br /> ' EHD <br /> r2 1 WELL MONITORING AND EVACUATION <br /> A Solinst water level meter was used to measure the depth to ground water in fifteen monitoring <br /> wells at the subject site relative to the tops of the well casings The ground water elevation, flow <br /> direction 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 plastic bailers or a two-stage submersible pump The pump was decontaminated prior to <br /> ' purging each well using an Alconox solution and clean tap water Approximately three casing-water <br /> volumes of water (approximately 4 to 50 gallons)were removed from the purged wells, however, <br /> wells MW-19A and MW-21B were bailed dry prior to evacuating three casing-water volumes <br /> ' Temperature,pH and conductivity of purged water were measured at regular purge-volume intervals , <br /> using an Oakton water analyzer The recorded field data and logs are included in Appendix A All <br /> 1 • purged water was stored in 55-gallon DOT-approved drums on-site <br /> 1 2 2 COLLECTION OF GROUND WATER SAMPLES <br /> Water samples were collected from each monitoring well using new disposable bailers after allowing <br /> ' the wells to achieve a minimum 80%recovery of the pre-purge water volume Water samples were <br /> collected from each purged well using new disposable plastic bailers Samples were transferred into <br /> 40-m1 EPA-approved VOA vials containing 0 5 ml 18%hydrochloric acid as a sample preservative <br /> ' and into 1-liter amber bottles without preservative The samples were labeled, stored on ice and <br /> transported under chain-of-custody to McCampb ell Analytical,Inc (MAI),a California Department <br /> of Health Services (DHS)-certified analytical laboratory Each sample was analyzed for <br /> • TPH-g, TPH-d and TPH-mo in accordance with EPA Methods 5030/8015 and 3550/8015, <br /> respectively, and <br /> ' • BTEX and methyl tertiary-butyl ether(MTBE) in accordance with EPA Method 8021B, <br /> In addition, samples collected from wells MW-19A through MW-21B were analyzed for fuel <br /> oxygenated compounds - tertiary butanol (TBA), di-isopropyl ether (DIPE), ethyl tert butyl ether <br /> (ETBE),tert amyl methyl ether(TAME),MTBE and trichloroethene(TCE)by EPA Method 8260B <br /> Advanced GeoEnvironmental,Inc <br /> 1 <br />