Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPThe New Cooling Tower will be removed down to its underground structure prior to the initiationof Phase 1 decommissioning activities.The Sewage Treatment Plant, the South Waste Tank Farm Test Tower, the two DemineralizerSludge Ponds, the Equalization Basin, the Equalization Tank, and the remaining concrete floorslabs, foundations, and hardstands will be removed.The Phase 1 work does not include the Rail Spur.F.7 Conceptual Site ModelWMA 6 potentially has impacts from a variety of releases. Some of these are surface, and someare subsurface. In addition, surface soil reworking in specific areas of WMA 6 has possiblyresulted in subsurface soil contamination. Specifically:• WMA 6 surface soils were likely affected by the 1968 airborne releases of radioactivityfrom the Process Building stack in WMA 1. These impacts would have originally beengreatest proximal to the Process Building and decreased as one moved south in WMA 6.Since 1968, however, there has been significant surface soil reworking in the northernportion of WMA 6. These activities could have removed contaminated soil layers, buriedthose layers under clean backfill, and/or redistributed/mixed contamination in surfacesoils.• Activities and buried infrastructure associated with the Old Sewage Treatment Facilityare known to have resulted in significant soil contamination that likely remains and thatmay be buried. The exact location of these infrastructure footprints is currently unknown.• The original old sewage treatment plant discharge channel that traversed the centralportion of WMA 6 was contaminated and then buried with clean soil. Subsurface soilcontamination likely remains associated with that original footprint. There are indicationsthat there may low level groundwater impacts associated with this contamination as well.Rev. 1 F-10