may need to be recovered from spent reactor fuels and refabricated into new fuel elements. As a by-product of fuel reprocessing, substantial amounts of curium will be available. This likelihood of increased curium production has, therefore, elevated concern for knowledge of its potential environmental transport following accidental contamination. Most of the previous conclusions on the biological transport of curium have strongly indicated that actual curium data must be obtained directly, rather than by making extrapolations from previously collected plutonium data. Retention differences between plutonium and curium have been noted in bone following intramuscular nuclide doses. One month after an intramuscular dose of curium-242 nitrate was given to rats, 20 percent of the total injected dose was retained in bone, compared to 41 percent for plutonium nitrate (Nenot et al., 1972). Plutonium was also apparently bound more firmly by protein in many molecular situations (Taylor, 1972), and it has been suggested that perhaps complex formation with protein may be more important in plutonium transport and tissue deposition than is the case with curium. McClellan et aZ. (1972) exposed 24 beagle dogs to aerosols of curium-244 which were inhaled as either the chloride or the oxide. The rapid loss of curium from liver previously observed in rats (Hamilton, 1947) was not noted in dogs. Urinary clearance and tissue retention patterns were somewhat similar between dogs exposed to the relatively soluble chloride and those exposed to the relatively insoluble oxide. Information obtained from this beagle study differed somewhat from the transport characteristics of various plutonium forms (Bair, 1970), but it has also been recognized that conclusions derived from inhalation studies necessitate a consideration of particle size (Bair, 1970; McClellan, 1972) as well as the anatomic location of particle deposition (Stather and Howden, 1975). Results from another study using beagle dogs (Lloyd et al., 1974) have indicated that intravenously injected curium is excreted primarily in the urine. These investigators injected five beagles with approximately 2.6 uCi Cm-citrate/kg and noted that the average urinary curium output one day after injection was approximately five times greater than the average fecal excretion of curiun. Furthermore, tissue concentrations one week after injection revealed that approximately 39 and 37 percent of the curium dose had been retained in the canine liver and bone, respectively. Curium metabolism in dairy animals has not been extensively investigated. However, it is particularly important to establish the metabolic retention and excretion patterns of curium in those domestic animals maintained as a source of food for the human population. The current experiment using dairy goats was designed to examine the metabolic pattern of curium following oral and intravenous exposure. Additional objectives were to compare the biological transport of curium and plutonium in the goat for relative hazard evaluation and to help establish an appropriate oral curium dose for more elaborate future studies using the major milk producers, i.e., dairy cows. 168