Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPPhase 1 will not address the NDA itself and the associated Interceptor Trench.G.7 Conceptual Site ModelHistorical activities within the WMA 7 footprint have almost exclusively been associated with theNDA. One would expect to find surface soil contamination impacts outside the NDAGeomembrane Cover resulting from dust deposition and discrete spills and leaks during NDA andSDA operation (the SDA is immediately adjacent to the east). It is likely contamination would bemore concentrated in drainage features and around the NDA hardstand. Historical gammameasurements support these assumptions.Because of the significant amount of soil reworking and re-contouring that has occurred withinWMA 7 over the years, it is possible that subsurface soil contamination exists, particularly alongthe northeastern and eastern edges of WMA 7 and potentially associated with buriedinfrastructure backfill that is present at the site. In addition, contaminated leachate/groundwaterassociated with the NDA has likely contaminated subsurface soils adjacent to and downgradientfrom the NDA.Figure G.17 shows the current Conceptual Site Model (CSM) for WMA 7 surface soils. Theportion of the WMA 7 area covered under the NDA Geomembrane Cover is not within thePhase 1 scope of activities.G.8 WMA 7-Specific Characterization Goals• Evaluate Appropriateness of the Current List of Radionuclides of Interest (ROI).• Verify Absence of Additional ROI.• Explore the Possibility of Surrogate ROI.• Determine Extent of Surface Contamination.• Identify the Presence/Absence of Subsurface Soil Contamination.• Identify Soil Waste Stream Characteristics.• Develop an Inventory of Buried Infrastructure.• Obtain Data to Support Phase 2 Planning.Rev. 1 G-10