Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPor may have occurred that likely impacted surface and subsurface soils and groundwater. Inaddition, environmental media within WMA 2 have likely been affected to some degree byreleases elsewhere at the WVDP site. These include air deposition contamination on surface soilsand subsurface contamination resulting from contaminant migration via groundwater from theProcess Building.During NFS operations, portions of the surface of WMA 2 underwent significant reworking. Thisreworking occurred in the western portion of WMA 2 and included the installation of Lagoons 4and 5 as well as additional facilities. This reworking may have covered contaminated surfacesoils with clean cover, contaminated surface soils may have been removed for dispositionelsewhere, and/or contaminated soils may have been re-used as backfill for building foundationsor buried infrastructure.Groundwater flow underneath WMA 2 is expected to be, in general, from west to east. The coreof the North Plateau Groundwater Plume has been steadily migrating in an easterly/northeasterlydirection. Groundwater flow also includes some northerly components along the west end of theCDDL, where discharge to the Swamp Ditch takes place, and also likely includes some southerlycomponents along the southern boundary of WMA 2, with discharge to Erdman Brook. Impactsto groundwater include the original Sr-90 release from beneath the Process Building in WMA 1,from leaching from Lagoon 1, from lagoon overflows (Lagoons 4 and 5), from seepage fromLagoons 2 and 3, and from various discrete releases associated with activities/infrastructure in thesouthwestern end of WMA 2.Figure B.19 shows the current CSM for surface soils. Figure B.20 shows the CSM for soilsdeeper than 1 m. Figure B.21 shows the CSM for contaminated groundwater beneath WMA 2.B.8 WMA 2-Specific Characterization Goals• Develop an inventory of buried infrastructure• Evaluate appropriateness of the current list of ROI• Verify absence of additional ROI• Determine extent of surface contamination• Identify the presence/absence of subsurface soil contamination• Identify soil waste stream characteristicsRev. 1 B-17