Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPsoils and a drainage feature that originally connected WMA 3 with the Old Hardstand ditches, butthat was subsequently filled with soils and paved.• A minimum of six soil trenches will be completed orthogonal to the drainage ditch thatoriginally ran along the west and north side of the Old Hardstand. These trenches will beto a minimum of 1 meter depth. Soils will be scanned for elevated activity as the trenchproceeds. A minimum of two samples will be collected from each trench. The first willrepresent those soils with the highest elevated activity. If the floor of the trench indicatesthat contamination above background levels extends deeper than 1 m, the trench will beextended vertically until there is no detectable evidence via scans of elevated activity inthe trench floor. The second soil sample will represent soils from final floor of the trench.All samples will be analyzed for the 18 ROI and the additional 12 radionuclides ofpotential interest. [required]• A minimum of three soil trenches will be completed orthogonal to the original drainageditch that connected WMA 3 with the Old Hardstand’s drainage features. These trencheswill be to a minimum of 1-m depth. Soils will be scanned for elevated activity as thetrench proceeds. A minimum of two samples will be collected from each trench. The firstwill represent those soils with the highest elevated activity. If the floor of the trenchindicates that contamination above background levels extends deeper than 1 m, the trenchwill be extended vertically until there is no detectable evidence via scans of elevatedactivity in the trench floor. The second soil sample will represent soils from final floor ofthe trench. All samples will be analyzed for the 18 ROI and the additional12 radionuclides of potential interest. [required]• If a 15 cm-1 m sample result exceeds background levels, then an additional sample froma depth of 1-2 m will be collected and analyzed from that location. In addition, downholegamma 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]Rev. 1 E-16