Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPDrainage features within WMA 12 South (including the streambeds and banks of Erdman Brookand Franks Creek) potentially would have been affected by the deposition of radionuclidecontamination from surface water sediment transport mechanisms.On the east side of WMA 12 South, it is known that historical activities in WMA 7 resulted incontaminated soils being displaced into drainage features that crossed into WMA 12 South.Other releases of significance include: (a) releases of elevated gross beta and Sr-90 through thepermitted sanitary outfall into Erdman Brook during 1970 through 1972, when a sewer line nearTank 7D-13 (in WMA 1) failed and allowed contaminated groundwater to enter the line and bedischarged through the outfall (WVDP-220; DOE 2010 Section 3.11.5); (b) discharges of trenchleachate from the SDA (WMA 8) before LLWTF operation began in 1972, as described in NFSquarterly reports; and (c) surface water runoff from the NDA (WMA 7) and SDA (WMA 8) overthe years.J.4.2Soil ContaminationPotentially Affected Media:Potentially Affected WMAs:surface soil, subsurface soil, sediments2, 12 (southern portion)There is evidence that contaminated soils/sediments from WMA 2 may have been pushed byconstruction or maintenance activities into WMA 12 South at some point in the past based onhistorical direct gamma readings and historical air photographs.J.4.3Wastewater Treatment OperationsPotentially Affected Media:Potentially Affected WMAs:surface soil, subsurface soil, groundwater, sediments2, 12 (southern portion) (Erdman Brook)Operational units used to treat radioactive wastewater are present in WMA 2. The design of someof these units allowed contaminated water to discharge to surface water in WMA 12 South(Erdman Brook) as part of standard operation. In particular:Rev. 1 J-3