Cytogenetic and Other Biological Effects of239 PuO2 Inhaled by the Rhesus Monkey

Sixteen immature rhesus monkeys were exposed via inhalation to an insoluble, polydisperse239 PuO2 aerosol labeled with ${}^{169}{\rm Yb}$ which had an activity median aerodynamic diameter of 1.6 μm and a xσ g of 1.6. Four groups with three monkeys per group were exposed to achieve initial239 Pu lung burdens of 1000-2000, 200-300, 20-65, and 2-10 nCi, respectively. To determine early retention and distribution of the aerosol, four additional monkeys were exposed with initial lung burdens of 200-600 nCi and were sacrificed 4 hr and 30 days after inhalation exposure. Two monkeys were sham exposed and served as controls. Using data derived from external whole-body counting of the ${}^{169}{\rm Yb}$ label, it was estimated that the inhaled239 PuO2 was retained in the body with an average effective half-life of 1000 days with some translocation from the lung to the pulmonary lymph nodes. Chromosome aberrations were scored in blood lymphocytes cultured 1, 3, 7, 19, 31, and 43 months after inhalation. Only in ani...