Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPareas less than 200 m 2 in size, one sample will be collected. For areas between 200 and1,000 m 2 in size, one sample per 200 m 2 will be collected. For areas between 1,000 and2,500 m 2 in size, five samples will be collected. For areas exceeding 2,500 m 2 in size, atminimum one sample will be collected per 500-m 2 area.• Sufficient soil mass will be collected to allow for the analysis of all 18 ROIs and 12potential ROIs; however, initial soil screening may focus on Cs-137 and Sr-90 ifevidence for the area of interest indicates that these are the only radionuclides ofsignificance from an SOR perspective. If the systematic soil sample soil screeningindicates the area likely meets surface soil CG w requirements, the 18 ROIs would beanalyzed to provide FSS-quality data sets.• If systematic surface soil sampling indicates that contamination exists above surface soilCG w requirements, soil sampling will be extended laterally until contamination isbounded spatially, if boundaries are not obvious from GWS data. If systematic surfacesoil sampling indicates contamination exists above background levels but below CG wrequirements, the lateral extent of systematic sampling may be extended until surfaceimpact extent is bounded.• In general (with the exception of sampling from wetlands in response to GWSinaccessibility), two samples will be collected from each location, one representative of a0- to 15-cm depth, and one representative of a 15-cm to 1-m depth. The purpose of the 0-to 15-cm sample is address the concern that elevated contamination levels might belimited to the immediate surface and exist at levels that would cause direct exposure doseissues, but that would be diluted by a 0- to 1-m depth sampling protocol. The purpose ofthe 15-cm to 1-m depth sample is to provide data that can be combined with data fromthe 0- to 15-cm interval to construct activity concentrations representative of andcomparable to the surface soil CG w definition. The exceptions to the two-sample-perlocationrequirement are areas where there is no evidence of historical surface soildisruption and no reason to be concerned about subsurface soil contamination. Anexample of this type of area would be portions of WMAs 4, 10, and 12. In these cases,CSAP surface soil sampling may be limited to only the top 0-to 15-cm depth interval.However, if only a 0- to 15-cm sample is collected at a location and the results of thatRev. 1 33