Distribution of Fallout Cesium-137 in Litter, Humus, and Surface Soil Layers Under Natural Vegetation in the Great Smoky Mountains

Since the explosion of the first nuclear weapon in July of 1945 and with subsequent tests, especially of hydrogen devices which contribute most of the world-wide fallout, and with the development of nuclear power plants, the world has become more and more interested in radioactive fallout and the problems related to it. During the detonation of a nuclear device some 170 radioactive isotopes are produced. Of these 170 isotopes there are seven principal gamma-ray-emitting fission products which have sufficiently long half-lives to be important in world-wide fallout (table I, adapted from Mortensen 1961). The purpose of this study was to measure the amount of cesium-137 in the organic layers and top four and one-half inches of mineral soil in representative evergreen and deciduous forest stands of the Great Smoky Mountains of North Caroling and Tennessee with emphasis on its distribution and movement downward through the soil.