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concentrations were assumed to be equal to concentrations found in soil leachate. <br /> Fate and transport modeling indicated that,with the exception of the groundwater plumes,the <br /> chemicals detected in the soil would not be detectable in'the groundwater. <br /> Public Law 104-160 prohibits residential reuse of this wildlife area. For agricultural reuse,the <br /> groundwater production rate must be greater than 200 gallons per day (gpd) and total dissolved <br /> solids (TDS)must be greater than 3,000 Nephlemetric turbidity units (NTL)). Results showed <br /> that the shallow water bearing zone (down to 15 feet) could not meet the production rate of 200 <br /> gpd, unlike the sandier layers below. In general,the TDS was greater than 3,000 in all the <br /> aquifers. Potential naturally occurring chemicals are being investigated. To date, there is no <br /> concurrence on background groundwater monitoring wells. <br /> The soils outside of the landfill cells do not appear to pose a threat to human health or water <br /> quality at any of the other sites. Additional studies must be conducted to determine the threats to <br /> ecological receptors. A beneficial-use study is pending to determine if the beneficial use of the <br /> aquifer could be realized irrespective of Navy occupancy. <br /> As a best management practice, the drainage channel banks sediment is excavated by the Navy to <br /> keep the drainage channels flowing, as the current elevation is below mean sea level. <br /> Approximately every two years,the Navy dredges the drainage channel and puts the sediment on <br /> top of the adjacent banks. Soil samples were collected from the drainage channel banks and <br /> analyzed for chemical constituents. <br /> Human health, ecological, and water quality assessments were subsequently conducted. The <br /> HHRA was run for a maintenance worker; the risks were determined to be very low. The ERA <br /> and WQA used conservative assumptions. In the WQA, any chemicals detected in the water that <br /> came through the soil column were assumed to be in the drainage channel surface water at that <br /> location. Fate and transport modeling showed that there were no detectable concentrations in the <br /> drainage channel surface water by the time the surface water reached the pump house. <br /> The results of the RI indicated that there are minimal threats to human health or to water quality; <br /> an additional ERA (i.e. Baseline ERA) is necessary to determine if the caps need to be extended <br /> to cover some of the soil outside of the landfill cells; the existing soil is inadequate as a final <br /> cover; and an engineered cap is used,the existing soil could support it, and the gas collection <br /> system is unnecessary. <br /> There are several other options in addition to the engineered cap, such as removal or <br /> consolidation of the cells into one capped location. <br /> Ms. Huey stated that a feasibility study(FS) must be conducted prior to selecting the remedy. <br /> Jim Austreng, DTSC, added that the Navy is required to evaluate community acceptance of the <br /> proposed remedy. Public comments will be addressed before the finalization of the remedy in the <br /> Record of Decision(ROD). <br /> 4 <br />