Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPsample. If biased samples are collected from a particular location, they will be collectedfrom two depth intervals: 0-15 cm, and 15 cm-1 m. The 0-15 cm samples will beanalyzed for the 12 radionuclides of potential interest in addition to the 18 ROI. Onedown-hole gamma scan will be conducted from each biased location. The purpose ofthese samples is to resolve GWS anomalies, evaluate the appropriateness of the currentROI list, and verify the absence of additional ROI. [contingent]• 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 5,surface soil CG w sampling in response to GWS results will primarily focus on areas thatare currently not paved; the paved central portion of WMA 5 will be addressed withsystematic gridded soil sampling.oIf GWS results indicate contamination impacts above background levels but thatsurface soil contaminant levels exceeding surface soil CG w requirements areunlikely, the area of interest will be systematically sampled using a triangulargrid with a density of one sample per 400 m 2 s. One sample will be collected fromeach location representative of a 0-15 cm depth interval. Locations will beselected so that they provide systematic coverage of the area of interest with atarget density of one sample per 200 m 2 area. The purpose is to document theactivity concentrations present in surface soils within WMA 5. [contingent]oIf GWS results indicate surface soil contaminant levels exceeding surface soilCG w requirements likely exist, one sampling location will be selected at thehighest gross activity level to confirm surface soil CG w exceedances and anotherset of sampling locations will be identified to spatially bound the extent ofcontamination (i.e., along the boundary of what is considered likely abovesurface soil CG w requirements) if this is not obvious from the GWS data. Twosamples will be collected from the location targeting high gross activity levels,one representative of a 0-15 cm depth interval, and one representative of a 15cm-1 m depth interval. One sample will be collected from each location intendedto laterally bound contamination, representative of a 0-15 cm depth interval. Inaddition, the location targeting high gross activity levels will have one down-holegamma scan conducted at the center of the location with static measurementsRev. 1 E-14