Lung Tumours in Monkeys After Inhalation of Actinides

Purpose: To determine the risks of lung tumors after inhalation of different actinides.

Status: 1972 - 1992

Treatment: Inhalation of Pu-239 dioxide (2.3μ AMAD, 0.6μ CMAD) prepared at 1000C

Dosimetry: Activity inhaled, activity retained, calculated average lung doses

Endpoints: Life-span study (spontaneous death) with macroscopic/microscopic pathology, sacrificed at terminal stage, radiographs of the thorax

Animal: 59 male and female baboons (Papio papio) 2-4 years (2-10 kg)

Results: A comparison of the early mortality (less than 1000 days) showed that the immature baboons had a similar sensitivity than the adult dogs studied at Batelle. Death at this time was mainly due to fibrosis, interstitial pneumonia and some lung tumors. Fibrosis and lung tumors were also the principal causes of death during the long-term observation period. A plot of log survival time against the log of Pu concentration in lung yielded a linear dependency which paralleled the curves obtained for dogs and did not significantly differ between these species. Plutonium was cleared from lung at an excretion rate (half life 600 - 3900 days) which decreased with time. Pu content of thoracic lymph nodes reached a maximum of 10-40% of initial lung burden about 1000 days after contamination.