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Second Quarter 2002 Monitoring and Sampling Report 5 <br /> 7-Eleven Inc Store No 17334,4501 North Pershing Avenue, Stockton CA July 29,2002 <br /> Conclusion and Recommendations <br /> ' As reported previously, field observations indicate the presence of a possible offsite contaminant source, a <br /> remediation system is present on the property located directly across North Pershing Avenue from the <br /> 7-Eleven site This finding may indicate plume mixing in the area of well MW-4 with another hydrocarbon <br /> source (not 7-Eleven) <br /> ' Other quarterly data obtained during this sampling event are consistent with previous findings, Indicating <br /> the onsite hydrocarbon source is In the vicinity of the underground storage tanks Wells MW-2, MW-3, and <br /> MW-513 were reported at low level to non-detectable concentrations for all analytes during the current <br /> ' monitoring event, suggesting stable plume conditions In general <br /> Non-detectable levels of dissolved plume constituents in the deeper nested well MW-513 Indicate vertical <br /> ' plume delineation near the source area <br /> Additional lateral plume delineation offsite is indicated based on current and historical dissolved oxygenate <br /> ' distributions, specifically MTBE levels of over 1,000 pg/L in well MW-4 Additional well Installation has <br /> been approved by the SJCPHS and access for offsite drilling is being actively pursued with offsite <br /> downgradient private/public property owners Once access to drill offsite has been obtained, the SJCPHS <br /> will be notified, it is expected that additional drilling can be completed within the next 90 days <br /> A workplan for interim remediation will be submitted as appropriate, based on feasibility evaluation findings <br /> If remediation is required by the SJCPHS, findings will be reported on a quarterly basis with groundwater <br /> ' analytical data <br /> 1 <br /> 17334Q22 QMR DOC <br />