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tl 7 it a I 1 ! 1 � I I ! f 1 X123 Decembe!r 2003 I ` I' AGE-NC Project No 97-0333 ' I PageA of 11 1 , i t , r r 'r f During the August and September 2003 monitonng events, effluent water samples detected TBA at concentrations as high as 80 micrograms per liter(peg/1)in the June 2003 sample Laboratory analysis ' ,of pump-and-treat effluent grab water samples did not detect any other constituents of concern Analytical results are summarized in Tabie 1, laboratory reports are in Appendix A I I ! ' Utilizing a Blue-White industries F-2000 flow meter,total flow(totalizer)was recorded between 19 kJune 2003 and 10 September 2003 (Table 5) During this time, the pump-and-treat interim remediation system was in operation for approximately 83 days Based on 218,888 gallons of water, I ' recorded during this time,AGE estimated that an average 2,637 gallons of water was discharged per r day during this time 5I , ' 26 MASS-VOLUME REMOVAL CALCULATIONS f I Between 19!4une 2003 and 10 September 2003, an estimated 6 6 pounds of MTBE was extracted from ground water (Table 5), since the system was initiated on 21 January 2002, a total mass of 215 16 pounds of MTBE has been removed The June 2003 to September,2003 mass-volume calculations of MTBE-impacted ground water extracted from the ground water pump-and-treat system are presented in Appendix B Plots of cumulative ground water pump and treat mass removal I trends and influent ground water MTBE concentrations versus time`are in Appendix C t I I ! 3.0: GROUNDWATER MONITORING AND SAMPLING' J� 4 I I On 18,119 and 20 August 2003,ground water monitoring and sampling were performed at 47 ground I I I water monitoring wells(MW-1 through MW;13) Quarterly groundwater monitoring procedures for , al ' the site were outlined in the AGE-prepared Work Plan Addendum, dated 03 April 2002,prepared by I AGE and approved by San Joaquin County Environmental Health Department(SJCEHD)by letter I dated 12 April 2002 As-built monitoring well construction details are summarized in Table 6'` k ' I , nth � 1 ' Ir„ II 3 1 WELL MONITORING AND PURGE PROCEDURES On 18 August 2003,Ithe 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 monitonng`well was calculated by subtracting the measured depth to ground water I' from the surveyed casing elevation(Table 2) Ground water elevation and vertical gradient data for j wells'M W-11, MW-12 and MW-13 are depicted m cross section F-F' (Figure 3),;ground water elevations were plotted in plan view for the informal First Zone, Second Zone, Third Zone and , Adv'a'nced I I I GeolEnvironmenlal,Inc �I I k !II IlIF+ "I II t ` I III I li I l I j