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30 October 2004 <br /> AGE-NC Project No 96-0232 <br /> Page 13 of 14 <br /> Furthermore, AGE suspects that the third MTBE-impacted ground water plume may have been <br /> influenced by ongoing Flag City Chevron ground water extraction activities, the plume appears to <br /> have been drawn onto Flag City Chevron property and towards the ground water extraction induced <br /> cone of depression(Figures 8 and 9) The recent migration of the third plume is further substantiated <br /> by the P-36, P-37 and P-38 grab ground water samples collected in First Zone and Second Zone <br /> (October 2002) that were non detect for MTBE <br /> Ground water Pump-and-Treat operations were fully suspended at the site on 17 August 2004 <br /> Between November 2000 and August 2004, a total volume of approximately 27,086,201 gallons of <br /> MTBE-impacted water was treated at the site Although a `spike' in MTBE concentration was <br /> reported in the July 2004 influent sample (47 µgll ), a general trend of decreasing MTBE <br /> concentrations is still evident at the site The July 2004 `spike' may be attributed to the above - <br /> referenced third MTBE-impacted ground water plume being drawn towards the Flag City Chevron <br /> extraction wells <br /> 6 0 RECOMMENDATIONS <br /> • Based upon data collected from the site, AGE recommends <br /> • Continued quarterly ground water monitoring and sampling of monitoring wells MW-1 <br /> through MW-19,future quarterly ground water monitoring events should be coordinated with <br /> the Three B's Truck Plaza investigation <br /> • AGE has made arrangements with the property owners at 6440 Banner Avenue(McDonald's <br /> Corportation) to install one dual-completed ground water monitoring well in the middle of <br /> their parking lot (see Figure 2) AGE has tentatively scheduled installation of the well to <br /> occur on 30 November 2004 <br /> In accordance with the RWQCB-approval letter dated 13 August 2004, AGE is in the process of <br /> preparing an evaluation of additional remedial alternatives (i a ozone sparge) An evaluation of <br /> additional remedial alternatives for the Flag City Chevron site will be submitted to the RWQCB no <br /> later than 15 November 2004 <br /> 7.0 LIMITATIONS <br /> Our professional services were performed using that degree of care and skill ordinarily exercised by <br /> environmental consultants practicing in this or similar localities The findings were based mainly <br /> upon analytical results provided by an independent laboratory Evaluations of the hydrogeologic <br /> Advanced GcoEnvironmental,Inc <br />