Of particular value is the Hanford Reach, the last portion of the Columbia River that supports salmon spawning. The nuclear reactors at Hanford used chromium in their cooling water to inhibit corrosion. Part of the chromium-containing effluent was discharged to the soil and subsequently migrated to the groundwater. Contaminated groundwater upwells into the Columbia River through the river bottom in the affected reactor areas. Organisms that live within the river bottom in these areas are exposed to toxic levels of chromium.
Young salmon are particularly sensitive to chromium.
Salmon adults excavate depressions in the river bottom, deposit their eggs, and then bury the eggs with gravel. The first few months of salmon development as eggs and alevin, are spent within the rocky river bottom. The 100-K Area completion is anticipated to lag by about three months.