Nuclear Engineering and Wildlife: Radioactivity in Jackrabbits after the Sedan Test

Abstract

After the Sedan thermonuclear test of July, 1962, at the Nevada Test Site, black-tailed jackrabbits (Lepus californicus) were collected from two areas within the local fallout pattern. The maximal tissue burdens measured were 9,700 nc of iodine-131 per gram of thyroid, 3.6 nc of cesium-137 per gram of muscle ash, 25.3 nc of strontium-89 per gram of bone ash, and 0.3 nc of strontium-90 per gram of bone ash. Estimated infinite doses to thyroids from iodine-131 were as high as 4,000 rems. The muscle of jackrabbits did not contain enough cesium-137 to render the meat unsafe; a person consuming one of the most highly contaminated rabbits might have incorporated 5 to 10 nc of cesium-137. Possible biological effects of the Sedan test in areas beyond the zone of close-in destruction are considered, and some problems in evaluating the ecological impact of nuclear engineering on wildlife resources are discussed. Research pertaining to wildlife resources and the development of atomic weapons and nuclear energy have been interrelated for more than 20 years. Following the construction of a plutonium plant on the Columbia River by the United States Atomic Energy Commission in 1943, the University of Washington was asked to examine the possible influences of the plant operations on the life of the river. The Applied Fisheries Laboratory was created and this work was carried out under the direction of Lauren R. Donaldson, a fisheries biologist. It is not surprising, then, that the attention of wildlife biologists was first focused on radioactivity in aquatic environments (Higgins 1950, 1951). But before the Bikini tests of 1946 there was little concern over the possible contamination of fisheries resources as a result of the uptake of radioactive materials by aquatic organisms. Hines (1962:35) points out: Although the concept of such circulation was not altogether new, its relevance in the Bikini situation seems not to have been realized, and (p. 24) that: there seems to have been no concern for the possibility of radioactive contamination of fisheries resources. .. . Of course the subsequent xperience of the British in Australia (Loutit and Russell 1961) and of our own biologists at the Nevada Test Site (Lindberg et al. 1954, 1959) showed that similar problems existed in land environments. Subsequently, radiation biology and studies of wildlife resources have been related in two ways. First, radionuclides have been us d in the study of management problems otherwise unrelated to radiobiology (Carrick 1956, McCabe and LePage 1958, Constantine et al. 1959, Fineman et al. 1963, Hanson and Case 1963). The use of radionuclides to mark individual animals has practically become a science in itself, and a good review of such procedures is available (Tester 1963). Second, radioactive substances occur in the environment, and may be detrimental to native plants and animals. Are there situations in which ani1This study was supported by contract AT(041) GEN-12 between the U. S. Atomic Energy Commission and the University of California. 2 Present address: Tempo, General Electric Co., Santa Barbara, California.