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I ` II 1 v e I 1 ' 07 December 2004 AGE-NC Project No 98-0448 I M Page 2 of 9 _ 1 • 23 September 2004-Monthly monitoring event performed on SVEJAS remediation system 1 Due to a crack in the IAS air compressor tank, the SVE/IAS remediation system was temporarily shut-down between 07 and 23 September 2004 ' 2.0. GROUND WATER MONITORING AND SAMPLING PROCEDURES On 03 September 2004,ground water monitoring and sampling was performed at the site on selected ' ground water monitoring wells Ground water monitoring and sampling procedures for the site were outlined in Remediallnvestigation/Feasibility Study Work Plan, dated 02 March 1999,prepared by AGE and approved by the San Joaquin County Environmental Health Department (SJCEHD) by ' letter dated 07 April 1999 As-built monitoring well construction details also are summarized in Table 1 ' 2 1 WELL MONITORING AND EVACUATION ' • During the September 2004 monitoring event, depth to ground water measurements were collected in monitoring wells MW-1 through MW-8 from the top of the well casing to the nearest 0 01-foot utilizing a Solinst water level meter The ground water elevation in each well was calculated by ' subtracting the measured depth to ground water from the surveyed casing elevation (Table 1) Ground water elevations were plotted and contoured on a scaled site map (Figure 3) After water levels were measured, approximately 6 to 13%gallons of ground water(a mimmum of three casing-water volumes per well)were evacuated(purged)from wells MW-1,MW-2,MW-4(A and B)and MW-6 utilizing a polyethylene disposable bailer Temperature,pH and conductivity were ' 1 measured for stabilization at regular purge-volume intervals from each well using an Oakton water analyzer Field data and logs are provided in Appendix A Purged ground water was containerized ' in properly labeled Department of Transportation(DOT)-approved 55-gallon drums and was stored on-site in an area lacking general public access I2 2 GROUND WATER SAMPLING ' Following well purging, the ground water level in each of the purged wells was allowed to achieve a minimum of 80%recharge prior to sample collection Ground water samples were collected from the purged wells utilizing new, disposable polyethylene bailers and transferred into 40-m1 EPA.- approved volatile organic analysis(VOA)vials containing 0 5 m118%hydrochloric acid as a sample preservative Care was taken to ensure that visible air bubbles were not present in the vials after Advanced CeoEnvironmental,Inc � 1