METHODS Tissue samples were collected from three cows, fetus in October 1973; two calves, three cows and two fetuses in July 1974; one cow and two yearling calves in January of 1975. sampled included three goats, coyote. and one and Other animals three foxes, one jackrabbit, and one The wildlife species are considered to be transitory resi- dents of the contaminated area. All animals sampled were necropsied; selected tissue and organ samples were collected for actinide analysis and histopathological examination. Tissues sampled for actinide analyses included bone (femur and vertebra), lung, liver, muscle, tracheo-bronchial lymph nodes, gonads, blood, kidney, rumen ingesta, and reticulum sediment. Those collected for histopathological examination were adrenal, eye, cardiac and skeletal muscle, gross lesions. liver, lung, gonads, spleen, thyroid, kidney, and Botanical and radionuclide data obtained from the rumen ingesta will supplement that collected from the fistulated steer portion of the study. In addition to those animals maintained in the contaminated area, fistulated steers are used as biological samplers to determine grazing habits as a function of plant availability and season, to estimate plutonium intake over specified periods of time, to determine the ratio of the actinide isotopes in the ingesta, and to estimate the percentage of digestable nutrients in the ingesta. At monthly intervals, for the first 6 months of the study, and at quarterly intervals thereafter, four fistulated steers were placed in the fenced area of,highest contamination for a 48-hr acclimation period. Following the acclimation period, their rumens were emptied of all ingesta and the steers were allowed to graze for a specific period of time. All ingesta from this controlled grazing period were removed for the various analyses required to meet the objectives of this portion of the study. 2, re 42