Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPG.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. Data collection will only take place in those portions of WMA 7 that are notcovered by the NDA geomembrane cover.G.9.1 Buried InfrastructureThe footprint of buried infrastructure will be identified and mapped. The focus would be onburied infrastructure that has footprints outside the NDA geomembrane cover. [required]G.9.2 Gamma Walkover Survey DataThe purpose of performing a gamma walkover survey of the WMA 7 area is to identify the leveland extent of surface contamination. This includes both general trends in average activityconcentrations pertinent to the CG w requirement, as well as the identification of isolated, moreelevatedanomalies that might be indicative of discrete releases and/or CG emc concerns.A complete (100%) logged gamma walkover survey (GWS) will be conducted for accessibleareas within WMA 7, with the exception of the NDA capped area. Examples of areas that wouldnot be accessible (besides the capped area) are areas where standing water is present in wetlands.This is most likely to occur in the northeastern corner of WMA 7. Based on the GWS results,surface soil within WMA 7 will be divided into four categories: (1) surface soils where GWS dataindicate contamination 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 G-11