Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAP• Define required extent of WMA 2 excavation• Obtain data to support Phase 2 planning• Obtain geotechnical data required for barrier wall designB.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.B.9.1Buried InfrastructureThe footprint of buried infrastructure will be identified and mapped. A significant amount ofburied infrastructure is believed to exist within WMA 2, and in particular in the western portionof WMA 2. This infrastructure would include wastewater lines as well as buried utilities.[required]B.9.2Gamma Walkover Survey DataThe purpose of performing a gamma walkover survey of the WMA 2 area is to identify the leveland extent of surface contamination. This includes both general trends in average activityconcentrations pertinent to the surface soil CG w requirement, as well as the identification ofisolated, more-elevated anomalies that might be indicative of discrete releases and/or surface soilCG emc concerns.A complete (100%) logged gamma walkover survey (GWS) will be conducted for accessibleareas within WMA 2. Examples of areas that would not be accessible are areas where standingwater is present in wetlands, existing building footprints, building pads, and lagoons. Based onthe GWS results, surface soil within WMA 2 will be divided into four categories: (1) surface soilswhere GWS data indicate contamination above CG w requirements; (2) surface soils where GWSdata indicate contamination, but it is not clear if contamination exceeds surface soil CG wrequirement; (3) surface soils where GWS indicate impacts, but those impacts are not expected toexceed surface soil CG w standards; and (4) surface soils where there is no indication of impactsabove background conditions. The purpose of this data collection is to provide insights into thespatial distribution of surface contamination, and to guide subsequent soil sampling. [required]Rev. 1 B-18