Retention , Excretion and Translocation of 239 Pu in Rats Following Inhalation of 239 PuO 2 Calcined at 1150 and 400 °

PuO2/Calcination temperature/Inhalation/Lung retention/Translocation Wistar rats inhaled PuO2 particles prepared by the calcination of Pu hydroxide at 1150 and 400°C. Lung retention, fecal and urinary excretion, and translocation of Pu were compared between the two calcination temperatures. The clearance of Pu from the lungs was significantly faster in the rats exposed to PuO2 calcined at 400°C (low-temperature group) than those exposed to PuO2 calcined at 1150°C (high-temperature group). Both the fecal excretion of Pu and the ratio of fecal excretion to urinary excretion was greater in the low-temperature group than in high-temperature group. The amounts of Pu translocated from the lungs to the other organs were very small. Even in the liver, which accumulated the largest amount of Pu except for the lungs, only 0.13–0.20% of the initial lung burden was retained 1 year after inhalation. The amount of Pu deposited in the liver was greater in the high-temperature group than in the low-temperature group both at 1 month and 1 year after the inhalation. These findings clearly suggest that the lung retention of Pu in rats is significantly affected by the calcination temperature of PuO2.