TRANSLOCATION OF PLUTONIUM FROM RAT AND MONKEY LUNG AFTER INHALATION OF INDUSTRIAL PLUTONIUM OXIDE AND MIXED URANIUM AND PLUTONIUM OXIDE

This study was designed to compare the translocation from lung of the Pu contained in the pure and mixed industrial oxides PuO2 and (U,Pu)O- 2. The latter had a Pu content of 20% w/w. For this purpose, young adu lt male rats and male and female baboons were exposed to a single inha lation of these oxides. Two baboons were exposed to the reference PuO2 , i.e. (PuO2)-Pu-239. Rats were killed under anaesthesia 1, 15, 30, 90 and 180 days after exposure, and baboons, also under anaesthesia, 1 y ear thereafter. The results indicate that lung retention of Pu was ind ependent of the oxide inhaled, but was smaller in rat (12-15% of the i nitial pulmonary burden, 6 months after exposure) than in baboon (56-8 0% of this burden, 1 year after exposure). In rat, Pu translocation ki netics were similar for the two industrial oxides, but as from day 15 after inhalation until 6 months thereafter, measurement of Pu deposits in the liver and skeleton showed that translocation of Pu from the mi xed oxide was 2-3 times greater than that from the industrial Pu oxide . In baboon, the largest amounts of Pu were retained in the lung and t horacic lymph nodes for the three oxides inhaled. Pu translocation to the liver, skeleton and kidneys, and also urinary Pu excretion, were g reater after inhalation of the mixed oxide than after inhalation of th e industrial and reference Pu oxides. Nevertheless, the amount of mixe d oxide Pu translocated to these sites and excreted in urine remained under 3% of the initial pulmonary burden.