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UP <br /> THOMAS R.FLINN P.O.BOX 1810-1810 E.HAZELTON AVENUE <br /> DIRECTOR STOCKTON.CALIFORNIA 96201 <br /> (209)468.3000 FAX(2D9)46&2999 <br /> Iwww.sjgov.org/puhworks <br /> THOMAS M.OAU <br /> CHIEF DEPUTY DIRECTOR `- <br /> MANUEL SOLORIO Wartb* 1c' YOU <br /> DEPUTY DIRECTOR <br /> STEVEN VWNKLER <br /> DEPUTY DIRECTOR <br /> ROGER JANES <br /> BUSINESS ADMINISTRATOR <br /> January 26, 2009 <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 AND ANNUAL 2008 GROUNDWATER AND SURFACE <br /> WATER MONITORING REPORT; FOOTHILL SANITARY LANDFILL <br /> Dear Mr. Del Frate: <br /> Enclosed is the Second Semester and Annual 2008 Monitoring Report for the Foothill Sanitary <br /> Landfill. Groundwater monitoring continues on a semi-annual basis in accordance with our <br /> WDRs. <br /> All wells are in compliance with concentration limits that can be validly derived. <br /> Analysis of groundwater flow direction indicates that well MW-4 is upgradient of the landfill, and <br /> that well MW-1 (previously considered upgradient) is actually crossgradient. <br /> Using data from MW-1 to calculate concentration limits has caused Sanitas to report false <br /> exceedences of concentration limits for sulfate and bicarbonate in several of the site's monitoring <br /> wells, including new background well MW-4. This situation will be rectified as data from new <br /> background well MW-4 provides new concentration limits for all parameters including sulfate and <br /> bicarbonate. Until sufficient data from MW-4 is available for that analysis, conclusions regarding <br /> possible groundwater impacts from Sanitas software will be tentative, and will be tempered with <br /> review of the data. <br /> Two VOCs were detected at trace concentrations in MW-2R in the July 2008 sampling event, but <br /> were not found in the subsequent resampling in August. We therefore conclude that the first <br /> analysis showed "false positive" results for those compounds. Other than false positive reports <br /> such as this, no VOCs were found in any wells this semester, and no VOCs have been confirmed <br /> in any groundwater well at the Foothill Landfill since October 2001, over seven years ago. <br /> Other results are unremarkable. <br /> Surface water was not available for sampling this semester. <br />