The effect of firing temperature on the lung retention and translocation of Pu following the inhalation of 238PuO2 and 239PuO2 by CBA/H mice.

Mice were exposed by inhalation to sized aerosols of 238PuO2 and 239PuO2 which had been fired at temperatures from 550-1250 degrees C and groups killed at times between 1 d and 2 y after exposure. Measurements were made of 238Pu and 239Pu in the lungs, lung-associated lymph nodes, liver and skeleton. With 239Pu, lung retention and translocation were independent of firing temperature. With 238Pu on the other hand, the retention in lung was greater initially than for 239Pu but, with the low-fired oxide, eventually fell below that of 239Pu. With high-fired oxides, the lung retention of 238Pu still exceeded that of 239Pu after 2 y. Translocation to liver and bone was invariably greater for 238Pu than for 239Pu and was also dependent on firing temperature. The practical implications of these findings are discussed.