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1 30 July 2004 AGE-NC Project No 96-0232 Page 7 of 16 During the second quarter 2004, an estimated 0 18 pounds of MTBE was extracted from ground water,to date,the ground water treatment system has removed a total of approximately 12 98 pounds of MTBE from extracted ground water (Table 8) Second quarter 2004 mass-volume calculations of MTBE-impacted ground water extracted from the ground water pump-and-treat system are _ presented in Appendix D Plots of cumulative ground water pump and treat mass removal trends and influent ground water MTBE concentrations versus time are in Appendix E 3.0. GROUND WATER MONITORING AND SAMPLING On 14 and 15 June 2004, ground water monitoring and sampling were performed at 37 single- or multi-level ground water monitoring wells (MW-1 through-MW-19) and at ten ground water extraction wells (EW-1 through EW-10), in addition, grab water samples were collected from two San Joaquin County service area No 31 municipal water wells (CSA-1 and CSA-2) on 14 June 2004 Quarterly ground water monitoring procedures for the site were outlined in the AGE-prepared Work Plan Addendum, dated 28 January 1998, and approved by the San Joaquin County Environmental Health Department(SJCEHD)by letter dated 24 February 1998 As-built monitoring well construction details are summarized in Table 9 A coordinated effort was made with Three B's Truck Plaza (14749 Thornton Road, Lodi CA) to conduct ground water monitoring activities concurrently, the Three B's Truck Plaza ground water elevation results and analytical results are in Appendix F 3 1 WELL MONITORING AND PURGE PROCEDURES On 14 June 2004, the depth to ground water was measured at each monitoring well from the top of each well casing to the nearest 0 01-foot utilizing a Solinst water level meter The ground water elevation in each monitoring well was calculated by subtracting the measured depth to ground water from the surveyed casing elevation(Table 4) Ground water elevation and vertical gradient data for wells MW-9,MW-11,MW-13,MW-16,MWA 7,MW-18 and Three B's Truck Plaza wells MW-6, MW-9 and MW-10 are depicted in cross section C-C' (Figure 3), ground water elevations were plotted for the informal First Zone, Second Zone, Secondary Aquifer Zone and Primary Aquifer Zone hydrogeologic units as defined in AGE's Final Remediation Plan (Figures 4, 5, 6 and 7, respectively) On 14 and 15 June 2004,approximately 5 to 8 gallons of ground water(a minimum of three casing- water volumes per well) were evacuated (purged) from wells MW-1 through MW-5, MW-6A, MW-7 and MW-16 utilizing disposable polyethylene bailers, approximately 40 to 81 gallons of groundwater were purged from wells EW-1,EW-3,EW-6 and EW-9 and 16%2 gallons from MW-6B utilizing a two-stage submersible pump Temperature, pH and conductivity were measured for Advanced GeoEnvironmental,Inc