Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAP• If contamination above background conditions is encountered at any selected location,trenching will continue to depth until background conditions are observed. An additionalsample will be collected from the base of the trench to verify background conditions. Thepurpose is to vertically bound observed contamination. [contingent]• If buried infrastructure soil sampling identifies contamination impacts greater thanbackground, biased sampling will continue following the line until at least twoconsecutive locations yield soil samples below surface soil CG w requirements. Locationspacing will be based on engineering judgment, including the geometry of the line, thelevel of contamination encountered, and surface evidence of contamination. Buriedinfrastructure characterization will not extend into the planned WMA 1 deep excavationfootprint. The purpose of this sampling is to bound the extent of contamination associatedwith buried infrastructure, as necessary. [contingent]A.9.6Additional ContingenciesSampling and/or GWS data may indicate that contamination exists or extends beneath surfacescurrently covered by existing structures, concrete, asphalt, or hardstand material. In this case,“surface soil” will be defined as soil immediately beneath the cover. If sampling or GWS dataindicate that contamination may exist beneath existing structures (e.g., existing buildings andbuilding pads), then sampling locations will be offset along the foundation edge to determinecontamination extent. The purpose of the offset is to allow safe acquisition of data. Datacollection through building pads and hardstands in WMA 1 will not be required as part of thiseffort.A.9.7Required Laboratory AnalysesAll samples will be submitted for analysis of all 18 ROI.A select portion of the samples as described above may be analyzed for the additional12 radionuclides of potential interest. In addition, ten percent of soil samples collected outside theWMA 1 excavation footprint will also be analyzed for the 12 radionuclides of potential interest. Ifthese sample results indicate the presence of the one or more of those radionuclides at levels ofRev. 1 A-20