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GRANITE CONSTRUCTION— FRENCH CAMP Page 6 <br /> WKA No 2088 09 <br /> October 10, 2005 <br /> Beginning in September 2003, Granite Construction connected to the City of Stockton's drinking <br /> water system On September 17, 2004, Henning Brother Drilling Company abandoned the onsite <br /> agriculture/dust control well under permit(permit No 39555) and supervision of SJCPHS <br /> A site plans showing groundwater elevation contours and flow direction for the October 29, 2005 <br /> ' monitoring and sampling event are illustrated on Plate No 2 Groundwater elevation data is <br /> summarized on Table 1 A summary of the analytical results for groundwater samples is <br /> summanzed on Tables 2 and 3 Well development/purging data sheets are included in Appendix <br /> A Complete laboratory analytical reports and Chain-of-Custody documentation are included in <br /> Appendix B <br /> Histone site plans showing Iocations of the former USTs, soil stockpiles and groundwater <br /> elevation contours and flow directions are included in Appendix C Boring logs and well <br /> construction details are included in Appendix D Historic tabulated chemical analysis of soil <br /> A samples obtained from borings is included in Appendix E The Checklist of Required Data for No <br /> Further Action Request at Underground Tank Sites Case Closure Summary data sheets is included <br /> in Appendix f and the Fee Title Certification is included in Appendix G <br /> Remaining Soil and Groundwater Contamination <br /> Soil containing residual petroleum hydrocarbons was removed from the site at the time of the <br /> ' UST removals However, trace concentrations of diesel (ranging from 1 1 mg/kg to 1 7 mg/kg <br /> obtained at depths ranging from 10 5 to 37 feet bsg) were reported in soil samples obtained from <br /> soil borings in the vicinity of the former USTs Concentrations of diesel (ranging from 87 to 180 <br /> µg/L), gasoline (220 µg/L), benzene (ranging from 0 56 to 12 µg/L), and MTBE (0 56 µg/L) <br /> were reported in water samples obtained from upgradient and downgradient wells in the vicinity <br /> of the former USTS <br /> It is our opinion that additional source removal at the site will be very costly, have little to no <br /> effect on the contaminant plume, and as such will provide no benefit in improving water quality <br /> beneath the site Furthermore, a decreasing trend in groundwater impacted with trace to <br /> moderate concentrations of petroleum hydrocarbons has been demonstrated since 1993 <br /> a <br /> WALLACE <br /> DD <br />'Recycled paper &ASSOCIAXES INC <br /> CL <br />