Repeated inhalation exposure of Beagle dogs to 239PuO2: retention and translocation

Whole-body retention and distribution of 239Pu in selected tissues of Beagle dogs were determined after a series of two or four inhalation exposures to 239PuO2. Exposures were made at half-year intervals with alveolar depositions of about 150 nCi per exposure. Data are reported on dogs followed for one and two years after the first exposure. The plutonium was found to be extremely insoluble; 2-3% of the amount deposited in the alveolar region translocated to tracheobronchial lymph nodes and less than 0.1% translocated to other tissues. The whole-body retention, when compared to retention of 239Pu following a single exposure, supported the hypothesis that each exposure was retained independently with the same retention characteristics. This is in agreement with results reported by other investigators for one human repeatedly exposed by inhalation to low levels of aerosols containing plutonium-uranium fuels.