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Peter MacNicholl <br /> January 28, 2005 <br /> Page 2 of 5 <br /> REVIEW ACTIVITIES <br /> The GSU was requested to evaluate the technical adequacy, content, and <br /> completeness of the subject report. The review was to focus on the hydraulic capture of <br /> the Central Area and the North Balloon trichloroethylene (TCE) and tetrachloroethylene <br /> (PCE) plumes, as well as on the comparison of site metal analytical results against <br /> background concentrations. Review activities consisted of reading the report, reviewing <br /> background information on the Defense Distribution Depot San Joaquin California, <br /> Sharpe Site (DDJC-Sharpe) Well Monitoring Program, and providing comments and <br /> recommendations as necessary. <br /> PROJECT SUMMARY <br /> The purpose of the Draft 2004 Annual Progress Report was to (1) summarize <br /> groundwater analytical data from all wells sampled and water level measurements <br /> obtained during the 2004 monitoring period (which includes sampling from October <br /> 2003 through September 2004), (2) present conclusions drawn from those results, and <br /> (3) provide recommendations for sampling, analysis, or remediation. <br /> GENERAL COMMENTS AND RECOMMENDATIONS <br /> A) The GSU commends the USACOE for including a dynamic three-dimensional <br /> conceptual model with the Draft 2004 Annual Progress Report. The GSU would also <br /> recommend including potentiometric contour lines on the geologic cross-sections to <br /> facilitate analysis of groundwater movement in the vertical plane as it relates to the <br /> movement of the groundwater contaminant plumes: <br /> Recommendation <br /> The GSU recommends revising the Draft 2004 Annual Progress Report to include <br /> potentiometric contour lines on all geologic cross-sections. <br /> SPECIFIC COMMENTS AND RECOMMENDATIONS <br /> 1) Figures 4.3-3 and 4.3-6 (TCE Concentrations in Groundwater in the D Zone, and <br /> PCE Concentrations in Groundwater in the D Zone, respectively): As depicted on these <br /> figures, two public water supply wells (PW020 and PW006) contained detectable <br /> concentrations of trichloroethylene (TCE) between 4Q03 and 3Q04, while one well <br /> (PW021) contained detectable concentrations of tetrachloroethylene (PCE). As <br /> presented in Appendix C (Time Series Plots), concentrations of PCE in well PW021 <br /> decreased between 1995 and 1999, but have remained relatively stable to the present. <br /> Reported concentrations of PCE in well PW021 have been above the USEPA maximum <br /> Sharpe_URS112204_FFAAnnualReport.doc <br />