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• i <br /> 5. Section 4.2, pages 4-1 and 4-2: This section compares soil gas measurements taken at <br /> the influent to the SVE system to the ROD cleanup standards; however, the comparison should <br /> be between soil gas measurements taken from soil vapor extraction or monitoring wells and the <br /> ROD cleanup standards. The ROD specifies that cleanup standards are for"...concentrations of <br /> PCE and TCE present in soil gas...." Since dilution occurs in the influent stream to the treatment <br /> system, the concentrations in soil gas are better represented from samples taken at the wells. <br /> Please use measurements taken at soil vapor extraction and monitoring wells,not at the treatment <br /> system influent, for future comparison to ROD cleanup standards for soil gas. <br /> MINOR COMMENTS <br /> 1. Section 4.0, Figure 4.2: The legend shows both 350 and 780 TCE isopleths,but the <br /> isopleths are missing their respective units, presumably ppbv. Please include the missing units in <br /> the next version of this document. <br /> 2. Section 2.0,Figures 2-2 through 2-5: There is no indication in the legend for Figures 2- <br /> 2 through 2-5 to define the measurements that appear with every well number. The values are <br /> assumed to be groundwater levels in feet above ms] at wells sampled in Above Upper, Upper, <br /> Middle and Lower Horizons. Presuming that the measurements are groundwater levels, please <br /> add a definitive note in the legend. <br /> 3 <br />