Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPG.9.3 Surface Soil SamplingSurface soil sampling will be used to address areas inaccessible to GWS data collection, toresolve hot spots identified by the GWS data, and to evaluate the presence, absence, and/or extentof surface contamination above CG w requirements based on GWS results.• Wetlands. It is possible that standing water will be present in wetlands that prevent GWSdata collection from those areas. The most likely place for this to occur is along theeastern boundary of WMA 7. Soil sampling will be required for wetland footprints andfor any other areas where standing water prevents the collection of GWS data.For every area where standing water or saturated soil conditions prevent GWS datacollection, systematic soil sampling will take place. For wetland areas less than 200 m 2 insize, one sample will be collected. For areas between 200 and 1,000 m 2 in size, onesample per 200 m 2 will be collected. For areas between 1,000 and 2,500 m 2 in size, fivesamples will be collected. For areas exceeding 2,500 m 2 in size, at minimum one samplewill be collected per 500-m 2 area. One sample will be collected from each locationrepresentative of a 0-15 cm depth interval. Locations will be selected to providesystematic coverage of the area of interest. [contingent]• 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. Surface soil sampling may be conducted after the GWS to further clarifyresults, with the level and nature of sampling dependent on GWS results. If GWS resultsindicate no evidence of contamination impacts above background levels, no additionalsurface soil sampling will be required other than to address areas too wet to perform aRev. 1 G-12