F-3.4 Pathways of Contaminant Migration and Exposure

The potential risk posed by contaminants in surface and shallow subsurface soil at WAGS 6 and 10 were evaluated by developing models to determine exposure pathways and receptors, and using bioenergetics-based exposure models to estimate exposure. However, an assumption that no pathway to ecological receptors exists for this medium was incorporated into the WAGS 6 and 10 ERA. Groundwater is considered inaccessible to ecological receptors because of the depth to the aquifer at the INEEL (60 to 180 m [200 to 900 ft]) and the large distance to surface springs (more than 160 km [ 100 mi]) (EG&G 1993). Waste Area Groups 6 and 10 soil COPCs include metals, organic compounds, and radionuclides.