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;TATE OF r4lIFGFlNIA-Environmental Protect .gency — PETE WILSON, Governor <br /> CAL- IF�fi :iA RE^.tl NAL WATER QUF. .. , CONTROL BOARD „Qom <br /> CE`JTRAL'.'AL,.7Y J19EGICN <br /> 3443 Routier Road,"uM A ENVIRONMENTAL HEALTH � <br /> Sacramento, CA 95827-3098 PFRMIT SERVICE , <br /> PHONE: (916) 255-3000 <br /> DOD FAk(916)255-3052 93 JUL —9 PM 2: 31 <br /> 6 July 1993 <br /> Mr. Abel Haines <br /> Environmental Protection Office <br /> Bldg. S-108, Sharpe Site <br /> Defense Distribution Region West <br /> P. 0. Box 960001 <br /> Stockton, CA 95296-0710 <br /> SIXTY PERCENT REMEDIAL DESIGN REPORT AND ANALYSIS, TECHNICAL SPECIFICATIONS <br /> FOR CENTRAL AREA OPERABLE UNIT (OU-1), DEFENSE DISTRIBUTION REGION WEST <br /> (DDRW), SHARPE, SAN JOAQUIN COUNTY <br /> We have reviewed the above referenced submittals received 4 June 1993. Our <br /> major concerns with the 30 Percent Remedial Design (RD) have been adequately <br /> addressed. Overall the reports are thorough and contain the elements needed <br /> to proceed to the 95 percent design phase. Our minor concerns with the 60 <br /> Percent Remedial Design Report and Analysis are discussed below. <br /> Appendix A of the 60 Percent Remedial Design Report and Analysis includes the <br /> Geotechnical Investigation Report (GIR) for the Proposed Percolation Pond and <br /> Groundwater Treatment Plant prepared by BSK & Associates. The GIR contains <br /> estimates of percolation and infiltration rates. However, the 60 Percent RD <br /> Report does not provide an evaluation to estimate pond effectiveness for <br /> disposal , using these data. An evaluation of percolation pond performance <br /> will provide an indication as to whether the pond will be reliable as the <br /> primary or secondary disposal option. In addition, data from recent injection <br /> tests performed by the Army Environmental Center in June 1993 should be <br /> evaluated and considered for the remedial design. The performance of the <br /> percolation pond and injection wells is critical to the long term remedial <br /> action objectives and should be thoroughly examined. 1 <br /> The GIR also presents the soil sample analytical data from the proposed I <br /> percolation pond. This data indicates slightly elevated levels (up to <br /> 227 mg/Kg) of total recoverable petroleum hydrocarbons (TRPH) . Further <br /> characterization of the pond is currently being conducted to quantify and <br /> speciate the hydrocarbons previously detected. In addition, soil samples will <br /> be analyzed for total and soluble metals from locations that exhibited the <br /> highest lead and arsenic in the GIR. Results of this additional <br /> characterization effort will determine if this contamination poses a threat to <br /> water quality. Should it be determined that a threat to water quality exists, <br /> then an appropriate remedial action must be considered prior to construction <br /> of the remedial design. Appropriate action may include segregation, <br />