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EPA Comments <br /> on the DD-Tracy <br /> Well Monitoring Program <br /> Quarterly Monitoring Report <br /> First Quarter 2001 Sampling Round, <br /> May,2001 <br /> GENERAL COMMENTS <br /> 1. Chemical concentration maps and evaluations of anomalous concentration measurements <br /> were not provided as requested a year ago. In its response to comments on the First Quarter 2000 <br /> Sampling Round report, the Defense Logistics Agency (DLA) stated that maps would be <br /> provided starting in the Fourth Quarter 2000 report. They were not. As previously stated in the <br /> comments for the "Well Monitoring Program Quarterly Monitoring Report,Fourth Quarter 2000 <br /> Sampling Round" report, the Quarterly Reports should include chemical concentration maps for <br /> trichloroethene (TCE) and tetrachloroethene (PCE), at a minimum, and to provide a brief <br /> evaluation regarding plume migration, the change in chemical concentrations since the extraction <br /> and treatment system began, and identification of new plumes, if relevant. In addition,please <br /> provide an evaluation of anomalous concentration measurements and how these measurements <br /> impact data usability and the current understanding of plume migration. <br /> 2. Figures 2-2, 2-3, 2-4, and 2-5 all contain errors in how the groundwater contours are <br /> drawn to reflect all available data. For example, in Figure 2-2 LM132AU, 56.03 feet above mean <br /> sea level (msl), should be within the 56 and 57 foot msl contours,not the 57 and 58 foot msl <br /> contours. Figure 2-3 may need a contour interval greater than 1 foot msl in the northeast corner <br /> of the map surrounding wells EW015A,EW016A, EW017A,EW018A and EW019A to <br /> correctly reflect their groundwater levels. LM077A, 50.81 feet msl, should be between the 50 <br /> and 51 foot msl contours, not between the 52 and 53 foot ms] contours. In addition, EW007A, <br /> 55.44 feet msl, should have a deeper depression than the 57 foot msl contour drawn next to it. In <br /> Figure 2-4, monitoring well LM051B, 55.52 feet msl, is shown between the 53 and 52 foot msl <br /> contours, and should be between the 55 and 56 foot msl contours. Figure 2-5 monitoring well <br /> LM128C, 62.88 feet msl, is shown between the 63 and 64 foot msl contours. Please correct the <br /> groundwater contours in the figures mentioned above so they accurately reflect the groundwater <br /> level in their respective horizons, or mark the wells as not being used to determine groundwater <br /> level contours. <br /> t <br />