Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPThe purpose of subsurface soil sampling within WMA 10 is to determine presence and verticalextent of contamination impacts above background levels.• If any 0-15 cm surface soil sample result indicates contamination impacts abovebackground levels and there was not a 15 cm-1 m sample collected from that location, a15 cm-1 m sample will be collected from that location following the protocols used forthe original 0-15 cm surface soil sample. In addition, each soil location will have onedown-hole gamma scan conducted at the center of the location with static measurementstaken every 15 cm. [contingent]• If a surface soil sample indicates contamination impacts above background levels for the15 cm-1 m depth interval, an additional sample from a depth of 1-2 m will be collectedand analyzed from that location. This process will continue until the vertical extent ofcontamination above background is bounded. One down-hole gamma scan will beconducted from each soil location requiring deeper investigation with a static readingtaken every 15 cm vertically. The purpose of these samples is to define the vertical extentof contamination. [contingent]I.9.5Drainage Feature SamplingPortions of WMA 10 include surface drainage features (i.e., ditches). For drainage features withinWMA 10, the surface soil CG w requirements apply. Surface drainage feature sampling will beconducted to determine ditch sediment contamination status relative to surface soil CGrequirements. Surface drainage features will be sampled as follows:• Samples representing a 0-15 cm depth interval will be collected from ditch sediments forthose ditches that have potential contamination concerns. In the case of WMA 10, this isabout a 90 m stretch of Erdman Brook extending from the WAM 6 boundary westward towhere the brook bifurcates into two feeder streams. Samples will be systematic locatedusing a random start, separated by 30 m. [required]• If any 0-15 cm sample result indicates contamination impacts above background levels, a15 cm-1 m sample will be collected from that location following the protocols used forthe original 0-15 cm sample. [contingent]Rev. 1 I-13