Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPhole gamma data will be collected from the location with static measurements collectedfor every 15 cm depth interval. If that sample has contamination above backgroundconditions, then the next deeper 1 m interval will be sampled and analyzed and a downholegamma scan performed. This process will continue until background conditions arereached. [contingent]• If systematic subsurface sampling identified contamination that appears to extendlaterally beyond the grid boundaries in WMA 3, then the grid will be extended andadditional sampling conducted until the lateral extent of contamination has been bounded.[contingent]C.9.5Buried Infrastructure Soil SamplingSoils associated with buried infrastructure within WMA 3 will be sampled to determine theircontamination status. Because of the likely complexity and amount of subsurface infrastructurefeatures within the WMA 3 area, these efforts will focus on infrastructure considered of greatestconcern, such as waste or wastewater lines and buried infrastructure footprints installed after1968 that potentially carried several different buried utility lines.• Three locations along each piece of buried infrastructure that is of concern within WMA3 will 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 boundarybetween WMA 1 and 3 or that intersects the planned footprint of the WMA 1 slurry wall,one of these locations will be at the boundary/slurry wall intersection. During excavation,exposed soils will be monitored by scans for evidence of elevated gross activity. Thepurpose of this sampling is to evaluate the presence of contaminated soils associated withburied infrastructure. [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 ofRev. 1 C-14