Toxicity of inhaled polydisperse aerosol of 239Pu(NO3)4 in Syrian hamsters. II

Syrian hamsters were exposed via inhalation to polydisperse aerosols of 239Pu(NO3)4 to define dose-response relationships. Animals were exposed in groups to achieve graded levels of initial lung burdens of 240, 60, 15, 3.8, 0.95, 0.24 and 0.029 nCi 239Pu. The aerosols had measured activity median aerodynamic diameters of 1.4 μm and a geometric standard deviation of 1.6. Animals were maintained both for serial sacrifice to determine radiation dose pattern and for life span observation to determine radiation dose-response relationships. Lung, liver and skeletal retention of 239Pu has been measured in the groups of animals and radiation dose to these tissues calculated. With only 10 animals remaining alive, excess mortality has been observed only in the highest level of initial lung burden group. Histopathologic observations are continuing on tissue samples obtained at necropsy