Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPanalyzed and a down-hole gamma scan performed. This process will continue untilbackground conditions are reached. [contingent]oIf systematic subsurface sampling identified contamination that appears to extendlaterally beyond the boundaries of WMA 1, such as into WMA 3, WMA 6, orWMA 10, then the grid will be extended and additional sampling conducted until thelateral extent of contamination has been bounded. In the case of WMA 3, samplingwill not extend beyond the planned slurry wall footprint. [contingent]A.9.5Buried Infrastructure Soil SamplingSoils associated with buried infrastructure of potential concern within WMA 1 will be sampled todetermine their contamination status. Buried infrastructure that is of potential concern in WMA 1is defined to be buried infrastructure that either carried contaminated waste/wastewater or wasinstalled after 1968.• Two locations along each piece of buried infrastructure that is of concern within WMA 1will be trenched. These locations will be selected to maximize the possibility thatcontamination will be encountered (e.g., locations where historical or current GWS dataindicate surface contamination exists). For infrastructure that crosses the planned WMA 1excavation boundary, one of these locations will be at the boundary. Trenching will nottake place within the planned WMA 1 excavation footprint. During excavation, exposedsoils will be monitored by scans for evidence of elevated gross activity. The purpose ofthis sampling is to evaluate the presence of contaminated soils associated with buriedinfrastructure. [required]oIf elevated readings are encountered below a depth of 1 m, soils exhibiting thehighest levels of gross activity will be sampled and analyzed.oIf elevated readings are not encountered below a depth of 1 m, a samplerepresentative of soils deeper than 1 m will be collected. In the case of infrastructurethat did not carry waste or wastewater, the sample will be from soils immediatelyabove the line. In the case of infrastructure that did carry waste or wastewater, thesample will be from soils immediately beneath the line.Rev. 1 A-19