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Work Plan Addendum -9- 21 September 1992 <br /> DDRW, Sharpe <br /> a. Hazardous concentrations of pesticides were found in the burn pit and South <br /> Balloon Area subsoils (page A-1) . It is unknown whether there was an <br /> adequate investigation of these areas to determine the lateral and vertical <br /> extent of contamination and whether these contaminated soil areas have ever <br /> been remediated. This is an example of why a spread sheet summarizing all <br /> of the WMU investigations are needed. <br /> b. A ground water sample from MW-407A was reported to have concentrations of <br /> PCBs (page A-2) . It is unknown samples from this well were analyzed again <br /> to confirm the presence of PCBs. Elevated levels of metals have been found <br /> in the soil samples from the dry wells (page A-4) . Ground water samples <br /> from MW-407A also have the highest concentrations of bromacil . It is my <br /> understanding that the contaminant concentrations in MW-407A may be <br /> associated to the dry wells located along the western boundary of the site. <br /> If the dry wells are associated with ground water contamination, then the <br /> use of these dry wells should be discontinued and the wells abandoned. <br /> c. It is unclear whether the elevated concentrations of lead and cadmium in <br /> the battery acid pit are associated with the elevated concentrations of <br /> cadmium found in several of the monitor wells (page A-3) . Some of the <br /> monitor wells which had elevated concentrations of metals, such as MW-416A <br /> do not appear to have been resampled to confirm the presence of elevated <br /> metals concentrations. <br /> d. Table 3.18 in Appendix A indicates that soil samples were collected from <br /> different WMUs and were analyzed for some heavy metals. However, upon <br /> examination it appears that only specific metals were analyzed for in these <br /> soil samples rather than conducting a complete scan of all potential metal <br /> contaminants. <br /> CKW:cw <br /> Attachments <br />