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'TATE OF CALIFORNIA + PETE WILSON, Governor <br /> CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD— 4 <br /> CENTRAL VALLEY REGION <br /> 3111143 ROUTIER ROAD, SUITE A p� <br /> SACRAMENTO, CA 95827-3098 <br /> 1'•,,,,,,,rd' <br /> PHONE. (916) 361-5600 <br /> FAX 1,9161 361-5686 <br /> SEP 2 5 1992 <br /> 21 September 1992 ENVIRONMENTAL HEALTH <br /> PtRMIT/SERVICES <br /> Mr. Abel Haines <br /> Environmental Protection Office <br /> Defense Distribution Region West <br /> P. 0. Box 960001 <br /> Stockton, CA 95296-0250 <br /> WORK PLAN ADDENDUM, DEFENSE DISTRIBUTION REGION WEST (DDRW), SHARPE, SAN JOAQUIN <br /> COUNTY <br /> We have reviewed the Work Plan Addendum submitted on 22 July 1992 for DDRW, <br /> Sharpe. In the February 1992 Draft Soils Feasibility Study (FS) Report, new <br /> source areas from non-fuel underground storage tanks (USTs) , with elevated <br /> concentrations of polychlorinated biphenyls (PCBs) and heavy metals in ground <br /> water samples, were reported for the first time. These findings necessitated that <br /> additional investigation be conducted to define the lateral and vertical extent of <br /> contamination in soils and ground water. This Work Plan Addendum was prepared to <br /> address the data gaps in the Draft FS Report. <br /> We are pleased that Sharpe has made an effort to address some of our concerns from <br /> our 17 April 1992 letter on the Draft FS Report. Sharpe has proposed to further <br /> investigate the extent of contamination in the area of several of the non-fuel <br /> USTs, the pesticide mix area and in the area of waste management unit (WMU) No. <br /> 26, all of which are in the North Balloon Area. Sharpe has also attempted to <br /> address our concerns regarding the use of soils gas data to evaluate volatile <br /> organic constituents (VOCs) contamination in the unsaturated zone and included in <br /> the appendix to the Addendum, a compendium of existing non-volatile data. <br /> However, we are concerned that many of our comments from our review of the Draft <br /> FS Report have not been addressed. Our major concerns with the Work Plan Addendum <br /> are summarized below and are discussed in more detail in the enclosed memorandum. <br /> 1 . There are several non-fuel USTs and WMUs that are not proposed for <br /> investigation. Among the most critical , are the two waste solvent tanks (Nos. <br /> 29 and 52) . UST No. 29 is not within the existing or proposed ground water <br /> extraction systems. If ground water contamination is found in the areas of <br /> the non-fuel USTs or WMUs, remediation must be included in the site-wide <br /> Record of Decision (ROD) . <br /> 2. Proposals for the soils contamination investigations, such as in the pesticide <br /> mix area and WMU No. 26, do not include analysis for soluble concentrations of <br /> contaminants. Soluble concentrations are needed to adequately assess the <br /> threat to the environment, specifically water quality. <br /> 3. The cleanup levels proposed in the Work Plan Addendum for total petroleum <br /> hydrocarbons (TPHs) , lead and chromium appear to be unacceptable because there <br />