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• "Assess total and dissolved metals concentrations near the IRM extraction system. <br /> • Assess changes in pesticide concentrations near the IRM extraction system." <br /> Since the pesticide and arsenic contamination appears to be localized near the interim <br /> remedial measure (IRM) system, these objectives may satisfy, in part, the intent of Comment <br /> No. 2. <br /> Corrective Action: DDRW-Tracy should revise the text to make it clear that assessment of <br /> total dissolved metals and pesticide concentrations are monitoring objectives. <br /> Previous EPA Comment No. 4 stated: <br /> "Figure 3-1 and upper horizon groundwater elevation data present a very obvious <br /> drawdown of the water table in the northeast corner of DDRW-Tracy. This effect on <br /> upper groundwater elevations in that area could very well be the result of pumping <br /> from a downgradient well drawing from the upper horizon. Based on well locations <br /> presented at the time of this report, there appear to be no downgradient wells that <br /> would have the potential to cause this drawdown. MW has made no attempt to <br /> explain this apparent drawdown in the upper horizon, and there are insufficient data <br /> points available in this area in all of the Upper Tulare formation to further explore the <br /> extent of the impact of the apparent drawdown. Additional data points in the upper <br /> horizon may need to be established to identify this potential pathway for migration of <br /> groundwater off-site should this trend continue. . . . Since well construction logs of <br /> the Pombo and Raspo private wells, shown on Figure 1-3, are not available, it is not <br /> possible to state whether heavy pumping at either of these wells might provide such a <br /> marked result in the upper horizon. At any rate, neither of these wells appears to be <br /> in a directly downgradient position from the apparent drawdown. Based on a cursory <br /> review of aerial photographs, (particularly March 1974 and July 10, 1982), one <br /> explanation that should be explored is the possible presence of a previously <br /> unidentified well in the area just downgradient of the apparent drawdown." <br /> However, EPA 's Comment No. 4 was not directly addressed in this report. The explanation <br /> would appear to be related to the fact that well LM35 is now believed to have been <br /> completed in the finer grained sediments termed "above Upper Horizon" rather than in the <br /> "Upper Horizon." <br /> Corrective Action: A more complete explanation as to why water levels should be different <br /> in the "above Upper Horizon" than in the "Upper Horizon" should be provided in this <br /> document. <br /> Previous EPA Comment No. 8 stated: <br /> "In Section 4.3.1.1., the statement is made that 'most of the measured concentrations of <br /> 2/3 <br />