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EPA Comments <br /> "Well Monitoring Program, Draft 1999 Annual Monitoring Report", <br /> December 1999, Tracy Defense Depot <br /> GENERAL COMMENTS <br /> 1. The Report does not provide the reasons for why extraction wells EW001, <br /> EW005AUA, EW007A, EW009B, EW035AU, and EW037AU were not operating in <br /> 1999. For clarity, please revise the Report to explain why the above- <br /> mentioned wells were not operating in 1999, whether they will be <br /> operating in the future and, if they won't be operating in the future, <br /> whether and when these wells will be abandoned. <br /> 2. The Report (Page ES-5, Section ES1.34) states that "some previously <br /> identified contaminants are not athreat to groundwater. Analytical <br /> results from the soil or from the extracts of waste extraction tests <br /> with deionized water indicated lower or no reported concentrations <br /> except dieldrin and TPH-diesel." However, Table 3 of Attachment 1 <br /> (Summary of Soil and Leachability Testing at SWMUs 7, 24, 30, and Drum <br /> Storage Area, DDJC-Tracy) indicates that the Deionized Water Waste <br /> Extraction Test (DI WET) Reporting Limits for several compounds are <br /> above the Cleanup Standards and that, therefore, the absence of <br /> contamination above the Cleanup Standard cannot be verified. The <br /> results of the DI-WET sampling indicated that TPH-D was detected at high <br /> leachate concentrations at SWMU 24 (Table 4) . At SWMU 33, TCE was <br /> detected above the MCL at LM002A. Therefore, please revise the Report to <br /> discuss the detection of TCE at SWMU 33, the fact that some method <br /> reporting limits were above the cleanup standards and how the findings <br /> of the leachability testing will affect the institutional control status <br /> of these SWMUs. <br /> 3. As shown in Table 4.1-1 (Page 4-10) , many of the extraction wells were <br /> not sampled because the pumps were not operating. It is unclear why no <br /> samples could be collected from the wells since there are several ways a <br /> sample can be collected from an extraction well when the pump is not <br /> operating. For example, if the pump was not operating because it was in <br /> the off-cycle during a cycling mode, the pump can usually still be <br /> operated using manual controls. If the pump was broken, it could be <br /> pulled out of the well (which needs to be done to repair the pump <br /> anyway) and the well could be sampled like amonitoring well. Please, <br /> revise the Report to indicate why a non-operational pump prevented <br /> sample collection and whether a concerted effort was exerted to collect <br /> samples from the extraction wells. <br /> 1 <br />