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PQtV 11y_ A-Arw IMP <br /> y= THOMAS R. FLINN P.0.BOX 1810-1610 E.HAZELTON AVENUE <br /> a. DIRECTOR STOCKTON,CALIFORNIA 95201.3018 <br /> (209)468-3000 FAX(209)468-2999 <br /> www.sjgov.org/pubworks <br /> THOMAS M.GAU <br /> CHIEF DEPUTY DIRECTOR <br /> `W®'Ar iTt fe, `Y,0(U <br /> MICHAEL SELLING <br /> DEPUTY DIRECTOR <br /> STEVEN WINKLER <br /> DEPUTY DIRECTOR <br /> ROGERJANES January 27, 2010 <br /> 1BUStNESS ADMINISTRATOR <br /> Mr. Todd Del Frate <br /> California Regional Water Quality Control Board <br /> Central Valley Region <br /> 11020 Sun Center Drive, #200 <br /> Rancho Cordova, California 95670-6114 <br /> SUBJECT: SECOND SEMESTER 2009 GROUNDWATER AND SURFACE WATER MONITORING <br /> REPORT; FOOTHILL SANITARY LANDFILL <br /> Dear Mr. Del Frate: <br /> Enclosed is the Second Semester 2009 Groundwater and Surface Water Monitoring Report for the <br /> Foothill Sanitary Landfill. Groundwater monitoring continues on a semi-annual basis in accordance with <br /> our WDRs. <br /> The upgradient Well MW-4 has been sampled four times since installation, which is not sufficient for <br /> analysis by Sanitas. The County has accelerated sampling from that well to obtain sufficient data as <br /> soon as feasible, but in the meantime, statistical analysis using data from MW-4 (previously considered <br /> upgradient) provides provisional conclusions. <br /> The water level at MW-1 can be measured, but it has dropped below an elevation where we can purge <br /> sufficiently to take a water sample. The County has scheduled the replacement of the pump to allow <br /> water sampling in February. This well is cross-gradient from the landfill, and not the background well. <br /> Five-year COCs were measured this semester. Several metals were detected, including Arsenic, <br /> Vanadium, and Chromium, mostly in trace concentrations, none exceeding 0.09 ppm. The metals and <br /> their concentrations in downgradient wells were similar to the upgradient well MW-4, indicating lack of <br /> impact to groundwater by the landfill. <br /> Semivolatile organic compounds (SVOCs) were not detected in this analysis. Previously, a number of <br /> SVOCs were reported in newly-installed wells MW-4 and -5: each well with the same compounds in <br /> similar concentration. The complete lack of these compounds in either well in this sampling event <br /> indicates that the previous report was a "false positive". Our consultant notes that these compounds are <br /> often found in cosmetics. <br /> General parameters minerals and inorganic results are unremarkable. <br />