Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPsurface soil sampling will be required other than to address areas too wet to perform agamma walkover survey.oIf GWS results indicate contamination impacts above background levels but thatsurface soil contaminant levels exceeding CG w requirements are unlikely, thearea 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 eachlocation representative of a 0-15 cm depth interval. Locations will be selected toprovide systematic coverage of the area of interest. The purpose is to documentthe maximum activity concentrations present in surface soils within WMA 12North. [contingent]oIf GWS results indicate surface soil contaminant levels exceeding CG wrequirements likely exist, one sampling location will be selected at the highestgross activity level to confirm CG w exceedances and another set of samplinglocations will be identified to spatially bound the extent of contamination (i.e.,along the boundary of what is considered likely above CG w requirements) if thisis not obvious from the GWS data. Two samples will be collected from thelocation targeting high gross activity levels, one representative of a 0-15 cmdepth interval, and one representative of a 15 cm-1 m depth interval. One samplewill be collected 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 thecenter of the location with static measurements taken every 15 cm. Locations willbe selected so that each representative area does not overlap. The purpose is todocument CG w requirement exceedances and bound the lateral extent ofcontamination. [contingent]oIf GWS results indicate areas with surface soil contamination impacts but it isunclear whether CG w requirement exceedances are present, at most five samplinglocations will be selected that systematically cover the areas of interest. Onesample will be collected from each location representative of a 0-15 cm depthinterval. Locations will be selected to provide systematic coverage of the area ofinterest with a maximum sample density of one sample per 200 m 2 area. TheRev. 1 K-7