100-HR-3 Operable Unit focused feasibility study

This Focused Feasibility Study (FFS) report presents a detailed analysis of alternatives for an interim remedial measure (IRM). The IRM addresses groundwater contamination in the 100-HR-3 Operable Unit. The focus of the FFS is chromium, a waste constituent that is transported by groundwater flow from the 100 Areas into the Columbia River. Ecological receptors in the river ecosystem may be exposed to chromium concentrations that exceed criteria established for the protection of aquatic life. The 100-HR-3 Operable Unit includes the groundwater beneath the 100-D/DR and 100-H reactor areas, and the intervening area (600 Area), as bounded by the Columbia River shoreline and the southern extent of the two reactor areas. Environmental restoration activities within the operable unit may be influenced by potential adverse impacts in adjacent areas, including groundwater, river water, riverbed sediments, and aquatic biota that may be exposed to contaminants as the result of groundwater flow from the operable unit. The starting point for selecting remedial alternatives for detailed analysis in the FFS is the 100 Areas Feasibility Study, Phases 1 and 2 (DOE-RL 1994a). This study presents a generalized view of applicable and implementable remedial technologies for contaminants of potential concern that are typical of all 100 Areas operable units. The FFS refines the analysis of remedial technologies for groundwater by incorporating contaminant characteristics and hydrogeologic conditions that are specific to the 100-HR-3 Operable Unit