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r ` 1 06 December 2002 AGE-NC Project No 97-0333 ' a Page 4 of 9 Utilizing a Blue-White Industries F-2000'flow meter, total flow (totalizer) was recorded between ' 06 June and 26 September 2002(Table 1) During this time,the pump-and-treat interim remediation system was in operation for approximately 76 days Based on 240,109 gallons of water recorded during this time, AGE estimated that an average 3,159 gallons of water was discharged per day ' during this time 2 6 , MASS-VOLUME REMOVAL CALCULATIONS 1 Between 06 June and 26 September 2002, an estimated 19 6 pounds of MTBE was extracted from ' ' ground water (Table 1), since the system was initiated on 21 January 2002, a total mass of 166 4 pounds of MTBE has been removed The June to August and August to September 2002 mass- ' volume'calculatlons of MTBE-impacted ground water extracted from the ground water pump-and- treat system are presented In Appendix C Plots of cumulative ground water pu ' 'and treat mass removal trends and influent ground water MTBE concentrations versus time are In Appendix D � 1 I ` 3.0. GROUND WATER MONITORING AND SAMPLING On 16 August 2002, ground water monitoring was performed at the site on,wells MW-1 through , MW-6, as-built monitoring well construction details are summarized In Table 3 Ground water ' monitoring procedures for the site were outlined In the AGE-prepared Work Plan Addendum - I, j August 1999, dated 10 August 1999 and approved by the San Joaquin County Environmental Health Department (EHD) by letter dated 25,August 1999 ' 3 1 WELL MONITORING AND EVACUATION „ Depth kto ground water was measured in each well from the top of the well casing to the nearest ' 0 01-foot utilizing a,Solmst water level` meter The ground water elevation in each well was I calculated by subtracting the measured depth to ground water from the surveyed casing elevation (Table 4) Groundwater elevations were plotted and contoured on a scaled site map (Figure 3) , After water levels were measured, approximately 4 to 111 gallons of ground water (a minimum of three casing water-volumes per well) were evacuated (purged) from wells MW-1 through MW-6 utilizing polyethylene disposable bailers Temperature, pH and conductivity were measured for stabilization at regular purge-volume intervals from wells MW-1 , MW-3, MW-4 and MW-5 using an Oakton water analyzer, however, data from wells MW-2 and MW-6 was not monitored for ' ,P stabilization because of the presence of approximately 4 to,5 Inches of floating product In these Advahced CeoEnvlronmental,Inc I' I