Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPactivities to the south in adjacent WMA 4 did not identify plume impacts as far north as WMA 12North.K.8 WMA 12 North-Specific Characterization Goals• Evaluate appropriateness of the current list of Radionuclides of Interest (ROI)• Determine level and extent of surface contamination• Determine level and extent of sediment contamination• Identify soil waste stream characteristics• Obtain data to support Phase 2 planningK.9 CSAP Pre-Remediation Data Collection and Associated Decision-MakingCSAP pre-remediation data collection will consist of a number of components described in moredetail below.K.9.1 Gamma Walkover Survey DataThe purpose of performing a gamma walkover survey of the WMA 12 North area is to identifythe level and extent of surface contamination. This includes both general trends in averageactivity concentrations pertinent to the CG w requirement, as well as the identification of isolated,more-elevated anomalies that might be indicative of discrete releases and/or CG emc concerns.A complete (100%) logged gamma walkover survey (GWS) will be conducted for WMA 12North for accessible areas. Examples of areas that would not be accessible are areas wherestanding water is present in wetlands or ponds. Based on the GWS results, surface soils withinWMA 12 North will be divided four categories: (1) surface soils where GWS data indicatecontamination above CG w requirements; (2) surface soils where GWS data indicatecontamination, but it is not clear if contamination exceeds surface soil CG w requirement; (3)surface soils where GWS indicate impacts, but those impacts are not expected to exceed surfacesoil CG w standards; and (4) surface soils where there is no indication of impacts abovebackground conditions. The purpose of this data collection is to provide insights into the spatialdistribution of surface contamination, and to guide subsequent soil sampling. [required]Rev. 1 K-5