Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAP• Hot Spots. If GWS data indicate the presence of contamination that possibly exceeds“hot spot” (CG emc ) standards or an isolated elevated area is identified that appearsindicative of a discrete release, the location of concern will be sampled with a biasedsample. If biased samples are collected from a particular location, they will be collectedfrom two depth intervals: 0-15 cm, and 15 cm-1 m. The 0-15 cm samples will beanalyzed for the 12 radionuclides of potential interest in addition to the 18 ROI. Onedown-hole gamma scan will be conducted from each biased location. The purpose ofthese samples is to resolve GWS anomalies, evaluate the appropriateness of the currentROI list, and verify the absence of additional ROI. [contingent]• CG w Sampling. Accessible WMA 3 areas will undergo systematic sampling for surfacecontamination concerns. Sampling locations will be arranged on a systematic, triangulargrid with a grid separation of 20 m. Two samples will be collected from each location,one representative of a 0–15 cm depth and one representative of a 15 cm–1 m depth.Depth will be measured from the interface of cover material and soils. Down-hole gammadata will be collected from each location with static measurements collected for every 15cm depth interval. An estimated 20 locations will undergo this data collection. [required]• If systematic surface soil sampling identifies contamination that appears to extendbeyond the boundaries of WMA 3 into either WMA 5 or WMA 10 and has not beenlaterally bounded by sampling activities in those WMAs, the sampling grid will beextended and sampling continue following the protocols described above until theencountered contamination is laterally bounded. [contingent]C.9.4Subsurface Soil SamplingThe purpose of subsurface soil sampling within WMA 3 is to determine presence and verticalextent of contamination impacts above background levels. The whole of the WMA 3 area isconsidered as potentially having subsurface contamination at depths greater than 1 m. Note thatburied infrastructure concerns may, in some instances, prevent vertically bounding subsurfacesoil contamination that is encountered.• 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, down-Rev. 1 C-13