Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAP• There were eleven groundwater sampling locations on the perimeter of WMA 10,including three along its boundary with WMA 1, that have historical sample results inELIMS. Figure I.13 shows Sr-90 results from these programs with locations color-codedby whether activity concentrations were ever observed greater than 10 pCi/L. Figure I.14shows the same type of map for tritium, with locations color-coded by whether activityconcentrations were ever observed greater than 500 pCi/L. The detection limits for Sr-90and tritium varied widely among ELIMS samples. 10 pCi/L and 500 pCi/L were selectedas thresholds for Sr-90 and tritium, respectively, because based on ELIMS data resultsabove these activity concentrations were consistently above method detection limits andso indicative of contamination impacts rather than simply measurement error. There wassome evidence of groundwater impacts along the boundary with WMA 1.I.6 Planned Phase 1 DP ActivitiesA number of existing structures will be removed down to their slabs either prior to Phase 1 DPactivities or as part of the Phase 1 activities (DOE 2009 Sections 3.1 and 7.10).These include:• the New Warehouse• the Vitrification Cold Lab and Expanded ELAB along with adjacent supporting structures• the former Waste Management Area• the Administration Building• the Changing Facility• the Vit Hill trailers and adjacent supporting facilities, and• the Diesel Fuel BuildingThese buildings were not impacted by on-site activities and are not expected to be contaminated.As part of the slab removal process, the top 2 feet of soil are expected to be removed along withthe slabs.Phase 1 will not address the Meteorological Tower and the Security Gatehouse.Rev. 1 I-7