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' 19 November 2004 <br /> AGE-NC Project No 99-0559 <br />' Page 2 of 7 <br /> 2.0• PROCEDURES <br /> Ground water monitoring and sampling were performed on 16 September 2004 The work was <br />' performed in accordance with guidelines established by the California Regional Water Quality <br /> Control Board (CRWQCB) - Central Valley Division for subsurface investigation of underground <br /> storage tank (UST) sites, and with the San Joaquin County Environmental Health Department <br />' (EHD)-approved Preliminary Site Assessment Work Plan, dated 12 October 1999, and Interim <br /> Remediation and Site Assessment Work Plan, date 25 January 2001, both prepared by AGE <br />' 2 1 WELL MONITORING AND EVACUATION <br /> Depth to ground water was measured in well chambers A through E of the multi-level wells MW-5 <br /> through MW-7 from the top of the well casings to the nearest 0 01-foot,utilizing a Slope water level <br /> meter,ground water elevations and gradients in this report are based on the measured depths Ground <br />' water was not observed or measurable in single-level wells MW-1 through MW-3, although free <br /> product was encountered, these wells were considered dry <br /> 10 After ground water depth measurements, well chambers B through E of the multi-level monitoring <br /> wells MW-5 through MW-7 were purged by lowering and raising a 3/8-inch outer diameter, length- <br /> discrete polyethylene hose equipped with a ball-valve water tip through the top chambers into the <br /> specific water-charged screened section, well chamber A was not purged or sampled due to lack of <br /> water in the chamber Approximately 125 to 4 gallons of ground water(a minimum of three casing- <br /> water volumes per well),when available,were removed from the multi-level monitoring well levels <br /> B, C, D and E Temperature, pH and conductivity were measured for stabilization at regular purge- <br /> volume intervals during monitoring using an Oakton water analyzer, field data and logs are included <br />' in Appendix A Purged ground water was containerized in 55-gallon drums and processed on-site <br /> for discharge under permit <br />' Dedicated, disposable polyethylene bailers were utilized to purge standing free product and water <br /> from wells MW-I through MW-3 <br />' 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Prior to ground water sampling,the ground water level in each well was measured to ensure that the <br /> well achieved a minimum of 80 percent recharge Following depth measurement, ground water <br /> samples were collected from well chambers B through E of multi-level wells MW-5 through MW-7 <br /> utilizing 3/8-inch diameter polyethylene tubing The ground water samples were transferred into <br /> three 40-nil EPA-approved volatile organic analysis (VOA) vials containing 0 5 ml 18% <br /> Advanced GeoEnvironmental,Inc <br />