Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAP• CG w Sampling. Surface soil sampling may be conducted after the GWS to further clarifyresults, with the level and nature of sampling dependent on GWS results. For WMA 2,surface soil CG w sampling in response to GWS results will primarily focus on areas thatare currently not paved and that are not within the planned WMA 2 excavation footprint.oIf GWS results indicate contamination impacts above background levels but thatsurface soil contaminant levels exceeding surface soil CG w requirements are unlikely,the area of interest will be systematically sampled using a triangular grid with adensity of one sample per 400 m 2 . One sample will be collected from each locationrepresentative of a 0-15 cm depth interval. Locations will be selected to providesystematic coverage of the area of interest. The purpose is to document the activityconcentrations present in surface soils within WMA 2. [contingent]oIf GWS results indicate surface soil contaminant levels exceeding surface soil CG wrequirements likely exist, one sampling location will be selected at the highest grossactivity level to confirm surface soil CG w exceedances and another set of samplinglocations will be identified to spatially bound the extent of contamination (i.e., alongthe boundary of what is considered likely above surface soil CG w requirements) ifthis is not obvious from the GWS data. Two samples will be collected from thelocation targeting high gross activity levels, one representative of a 0-15 cm depthinterval, and one representative of a 15 cm-1 m depth interval. One sample will becollected from each location intended to laterally bound contamination,representative of a 0-15 cm depth interval. In addition, the location targeting highgross activity levels will have one down-hole gamma scan conducted at the center ofthe location with static measurements taken every 15 cm. The purpose is to documentsurface soil CG w requirement exceedances and bound the lateral extent ofcontamination. [contingent]oIf GWS results indicate areas with surface soil contamination impacts but it is unclearwhether surface soil CG w requirement exceedances are present, at most five samplinglocations will be selected that systematically cover the areas of interest. One samplewill be collected from each location representative of a 0-15 cm depth interval.Locations will be selected to provide systematic coverage of the area of interest. TheRev. 1 B-20