Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPoIf 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. Thepurpose is to resolve the question of whether CG w requirement exceedances existfor areas where GWS results are ambiguous. [contingent]oIf any 0-15 cm interval yields a sample result indicating a CG w requirementsexceedance and that sample location is not laterally bounded either by existingsampling locations with results less than CG w requirements or by GWS data thatclearly indicate contamination is not a concern, additional sampling locationswill be selected so that the contamination encountered is spatially bounded. Thepurpose is to laterally bound contamination that is above CG w requirements.[contingent]J.9.3Subsurface Soil SamplingThe purpose of subsurface soil sampling within WMA 12 South is to determine the vertical extentof contamination impacts above background levels.• If any 0-15 cm surface soil sample result indicates contamination impacts abovebackground levels and there was not a 15 cm-1 m sample collected from that location, a15 cm-1 m sample will be collected from that location following the protocols used forthe original 0-15 cm surface soil sample. In addition, each soil location will have onedown-hole gamma scan conducted at the center of the location with static measurementstaken every 15 cm. [contingent]• If a surface soil sample indicates contamination impacts above background levels for the15 cm-1 m depth interval, an additional sample from a depth of 1-2 m will be collectedand analyzed from that location. This process will continue until the vertical extent ofcontamination above background is bounded. One down-hole gamma scan will beconducted from each soil location requiring deeper investigation with a static readingRev. 1 J-12