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EPA Comments <br /> Draft "Project Closeout Plan (Remedial Action Report), <br /> SWMU 6, SWMU 20, and SWMU 27 Small Excavation Sites and SWMU 4 <br /> Wet Season Controls", dated March, 2001 <br /> Defense Distribution Depot San Joaquin California, Tracy Site <br /> Tracy, California <br /> GENERAL COMMENTS <br /> 1. The summary tables for SWMUs 6, 20 and 27 (Tables 4-2A, 4-2B, and 4-2C) <br /> show results that are marked with a less than symbol (<), indicating the results <br /> are "not detected above the practical quantitation limit", according to the notes <br /> in the tables. However, the practical quantitation limits (PQLs) on the <br /> analytical reports for these results in Appendix F are less than the posted <br /> results in the tables. The posted results appear to be reporting limits, <br /> apparently elevated due to correction for moisture content, based on the data in <br /> Appendix F. For example, in SWMU 6, sample location DP0091, the PQLs <br /> presented in Appendix F for the ROD-defined chemicals of concern (1.5 to 10 <br /> ug/kg) are less than the posted reporting limits (1.9 to 13 ug/kg). It is unclear <br /> why the summary tables (Tables 4-2A, B, and C) state that the results with the <br /> less than symbol are less than the PQL when Appendix F shows the results to <br /> be less than reporting limits higher than the PQLs. Please clarify the use of <br /> PQL versus reporting limits in the tables. <br /> 2. The reporting limits for sample DP0091 are all greater than the soil cleanup <br /> standards. This raises the issue of whether the cleanup goals were met at <br /> SWMU 6 because DP0091 was a confirmation sample collected to demonstrate <br /> that contamination was removed in the southern portion of the excavation. <br /> Since the reporting limits for the Site-Wide Comprehensive Record of <br /> Decision (ROD)-defined chemicals of concern exceed the ROD-specified soil <br /> cleanup standards, it is not clear why or how this sample was used to <br /> demonstrate that contamination was removed from the southern portion of the <br /> excavation. Please provide an explanation in the text justifying the usability of <br /> this data and how it was used to make remedial decisions, such as stopping <br /> excavation. <br /> 1 <br />