Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPcharacterize the nature and extent of that plume; additional characterization of the North PlateauGroundwater Plume is outside the scope of the CSAP.• WMA 2 Waste Characterization. Subsurface soil cores will be obtained within thefootprint of the planned WMA 2 excavation to address contaminated soil volumeestimation needs. Sixteen core locations will be placed within the excavation footprint(excluding the footprints of Lagoons 1, 2, and 3) to a depth of 1 m into the Lavery Till.The cores will be located to provide systematic coverage of the area (approximately onecore per 1,000 m 2 ). Each one meter interval of each core will be sub-sampled in a fashionto obtain a representative sample, and those samples submitted for quick turn-aroundanalysis of Sr-90 and Cs-137. With an average expected depth-to-till of 20 feet,approximately 100 samples will be collected and analyzed. These data will be used toestimate waste stream volumes resulting from the excavation of WMA 2. [required]• Lagoon 2 Sediment Characterization. Because of the placement of highlycontaminated Lagoon 1 sediments into Lagoon 2, there is the potential for TRUcontaminatedsediments to be present in Lagoon 2 sediments. Five locations will besystemically identified across Lagoon 2’s surface, and sediment cores retrievedrepresenting the top one meter of sediments/soils. These samples will be analyzed for the12 potential radionuclides of interest, in addition to the 18 ROI. [required]• Southern WMA 2 Excavation Boundary. Subsurface soil coring, scanning, andsampling will take place along the southern boundary of the planned excavation todetermine the contamination status of surface and subsurface soils adjacent to thesouthern edge of the planned WMA 2 excavation. An initial set of 30 sampling locationsseparated by 10 m starting from the southwestern corner of the WMA 2 excavation andrunning east along planned excavation boundary will be sampled (Figure B.23). At eachlocation, one core will be retrieved that extends one meter into the Lavery Till. A downholescan will be conducted to the extent possible at each location with a staticmeasurement every 30 cm. Each core will be divided into one meter segments.oAt minimum, the following soil core segments will be submitted for analysis: the topmeter (representative of surface soils), the meter directly above the Lavery Till, thetop meter of Lavery Till, and the meter straddling the water table. In addition, if theRev. 1 B-22