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:? U 16 June 2008 <br /> Messrs Trommer and Lon Page 2 of 7 <br /> _ Preliminary Five-Year Review Letters <br /> Various Sites <br /> i <br /> wells. The EHD is awaiting the groundwater extraction;,test report to comment on <br /> pump and treat; the absorbent appears to be for, free .product and has not been <br /> approved. ` <br /> F <br /> 2500 Lodi Avenue, W. <br /> • CUF recommended site closure consideration. A .t DPE test was recently <br /> conducted on MW-3; a report of findings is anticipated in the near future with a <br /> closure report addressing vapor intrusion potential and comparison to Region II <br /> ESLs. <br /> 345 Yosemite Street, N <br /> i <br /> • CUF recommended site closure consideration. The EHD does not agree with this <br /> I recommendation at this time for the following reasons.. The site has two UARs <br /> and separate site codes (503414 and 2216), but have been worked under one <br /> CUF Claim (#12858). The western former underground'storage tank (UST) site is <br /> nearly ready for closure consideration, but recent review shows that the vertical <br /> extent of impacted groundwater has not been demonstrated. Also, a sand unit <br /> that is a potential contaminant migration pathway was not sampled toward the <br /> northwest. The EHD will direct that these data be "acquired. The EHD also <br /> believes some attempt should be made it to reduce the contaminant <br /> concentrations more rapidly, perhaps some batch groundwater extraction. <br /> �I <br /> • The eastern former UST site (case #503414) is, not fully delineated laterally or <br /> vertically. Additional monitoring wells to complete:E the lateral and vertical <br /> assessment of the eastern UST is required. Following receipt of the report of <br /> monitoring well installations, assuming favorable!�analytical results, and sufficient <br /> quarterly monitoring of the new wells, this case}may :then be ready for closure <br /> consideration. As with the other case on the site, the; EHD also believes some <br /> attempt should be made to reduce the contaminant concentrations more rapidly, <br /> perhaps some. batch groundwater extraction. The RP will be directed to evaluate <br /> the potential benefit from some remediation for both cases. <br /> 15406 Tracy Blvd. <br /> • CUF recommended consideration for site closure; the,i�EHD does not agree. with <br /> this recommendation at this time. Vertical delineation of impacted groundwater is <br /> not complete; the onsite domestic well, screenedsbetween 76 and 96 feet bsg, is <br /> approximately 100 feet from impacted monitoring well MW-4. A work plan will be <br /> submitted in the near future to advance two geoprobe borings downgradient of <br /> MW-4 for lateral and vertical delineation and to perform�a pumping test on MW-4; <br /> the EHD, in consultation with the CVRWQCB,I� believes this work should. be <br /> completed before closure consideration. <br /> 757 Eleventh Street <br /> • CUF recommendedevaluation of remedial technologies and potential for vapor <br /> intrusion. The EHD agrees with these recommendations, but notes that there <br /> were two UST systems with releases approximately 340 feet apart. The down- <br /> gradient and cross gradient extents of the dissolved plume centered on former <br /> 5-Year Review Comment Letter.061608.doc <br /> , <br />