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<br />' 15 October 2001
<br /> i AGE-NC Project No 96-0232
<br />' Page 7 of 17
<br />' MTBE-Impacted ground water extracted from the ground water pump-and-treat system are presented
<br /> in Appendix D Plots of cumulative ground water pump and treat mass removal trends and Influent
<br /> ground water MTBE concentrations versus time are in Appendix E
<br /> 1
<br /> 3.0. QUARTERLY GROUND WATER MONITORING AND SAMPLING EVENT
<br />' On 05, 06 and 07 September 2001, ground water monitoring and sampling were performed on 30
<br /> ground water monitoring wells(MW-1,MW-2,MW-4,MW-5,MW-6A,MW-613,MW-7,MW-8A,
<br />' MW-813, MW-8C, MW-9A, MW-9B, MW-9C, MW-10A, MW-1013, MW-10C, MW-101),
<br /> MW-10E, MW-11A, MW-11B, MW-11C, MW-IID, MW-12A, MW-1213, MW-12C, MW12D,
<br /> MW-13A, MW-13B, MW-13C and MW-13D) As-built monitoring well construction details are
<br />' summarized in Table 9
<br />' In addition, ground water samples were collected from 9 extraction wells (EW-2, EW-3, EW-4,
<br /> EW-5, EW-6, EW-7, EW-8, EW-9 and EW-10), two domestic drinking water wells [one located at
<br /> 14659 Thornton Road (RDW-1) and the other at 14749 Thornton Road (DW-1)], and two San
<br />' Joaquin County service area No 31 municipal water wells (CSA-1 and CSA-2) Quarterly ground
<br /> water monitoring procedures for the site were outlined in the Work Plan Addendum, dated
<br /> 28 January 1998, and approved by the PHS-EHD by letter dated 24 February 1998 A coordinated
<br /> effort was made with Three B's Truck Plaza (14749 Thornton Road, Lodi CA) to conduct ground
<br /> water monitoring activities concurrently, the Three B's Truck Plaza tabulated ground water elevation
<br /> results are in Appendix F
<br /> 1
<br /> 3 1 MONITORING WELL PURGE PROCEDURES
<br />' On 05 September 2001,depths to ground water were measured in the ground water monitoring wells
<br /> from the tops of the well casings to the nearest 0 01-foot utilizing a Solinst water level meter
<br />' Ground water elevations in each monitoring well at the site were calculated by subtracting the
<br /> measured depth to ground water from the surveyed well casing elevations (Table 4) Ground water
<br /> elevations were plotted for the informal First Zone, Second Zone, Secondary Aquifer Zone and
<br /> Primary Aquifer Zone hydrogeologic flow units as defined in Final Remediation Plan,
<br /> dated 31 August 2000 Ground water elevation data was contoured on scaled site maps (Figures 3,
<br /> 4, 5 and 6, respectively)
<br />' On 06 and 07 September 2001, approximately 4 to 12 gallons of ground water a minimum of three
<br />' casing-water volumes per well)were removed from wells MW-1, MW-2, MW-4, MW-5, MW-6A,
<br /> MW-613 and MW-7 utilizing a disposable polyethylene bailer Temperature, pH and conductivity
<br /> were measured for stabilization at regular purge-volume intervals from each well using an ICM
<br /> IAdvanced GeoEnvaronmental,Inc
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