A Description of Long-Term Environmental Monitoring and Assessment Programs at Two U.S. Department of Energy Sites

The U.S. Department of Energy's Hanford Site was established in southeastern Washington during the 1940s to produce plutonium, and the Pantex plant in Texas (used to load conventional ammunition shells and bombs) was rehabilitated in the 1950s to assemble nuclear weapons using the plutonium produced at Hanford. Current concentrations of airborne radionuclides around the perimeters of both sites are below applicable guidelines. Concentrations of radionuclides and nonradiological water quality in the Columbia River at Hanford and radiological and nonradiological water quality in the Ogallala Aquifer beneath the Pantex plant are also in compliance with applicable standards. Foodstuffs irrigated with river water downstream from Hanford show levels of radionuclides similar to those in foodstuffs from control areas. Levels of^{137}{\rm Cs}$and^{90}{\rm Sr}$in some on-site Hanford wildlife samples and concentrations of radionuclides in soils and vegetation on and off site at both locations are typical of naturally occurring radioactivity and worldwide fallout. The potential dose received by a maximally exposed individual at both sites in 1994 was ≤0.05 mrem; the average per capita dose was ≤0.002 mrem. By virtue of its size, restricted access, and conservative use of undeveloped land, the Hanford Site has become a sanctuary for plant and animal populations that have been eliminated from, or greatly reduced on, surrounding agricultural and range lands. The Hanford Reach of the Columbia River and its islands and the Pantex Plant with its playas serve as refuges for raptorial birds and migratory waterfowl. In addition, the Hanford Reach serves as a migration route for several species of salmon, and chinook salmon and steelhead trout spawn there. Bald eagles congregate along the Hanford Reach in the fall and winter to feed on the spawned-out carcasses of salmon and wintering waterfowl.