Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPK.9.2 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 highly likely that standing water will be present in the ponds/wetlandsthat prevent GWS data collection from those areas. Consequently, soil/sediment samplingwill be required for pond footprints and for any other areas where standing water preventsthe 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. In the case where an area has more than onelocation, locations will be selected to provide systematic 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, then 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. Sufficient soil mass will be collectedto allow for the analysis of all 18 ROI. All samples will be analyzed for all 18 ROI. Onedown-hole gamma scan will be conducted from each soil biased location with staticmeasurements taken every 15 cm. The purpose of these samples is to resolve GWSanomalies and evaluate the appropriateness of the current ROI list. [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 additionalRev. 1 K-6