Comparative biokinetics of plutonium and americium after inhalation of PuO 2 and mixed oxides (U, Pu)O 2 in rat

Abstract

Purpose : To compare the biokinetics of Pu and Am in rat after inhalation of PuO 2 and two (U, Pu) mixed oxides (MOX), referred to as MIMAS and SOLGEL. Materials and methods : Lung clearance was measured in vivo by X- and gamma-ray spectrometry. Retention of Pu and Am in femurs, liver and kidneys was measured by alpha-spectrometry. Results : Observed lung clearance was in the same range for all three powders. Extra-pulmonary transfers were expressed as the percent of the initial deep lung deposit (IDLD) measured 7 days after inhalation. After PuO 2 exposure, bone retention remained nearly constant throughout the 270-day experiment. It was ~0.7% of the IDLD for Pu and Am. By contrast, a gradual increase was observed for the two MOX. After 7 days, bone retention of Pu and Am was respectively 0.05 and 0.08% for MIMAS, and 0.2 and 0.6% for SOLGEL. The retention reached maximal values between 180 and 270 days post-exposure, which were 0.2 and 0.3% for MIMAS, and 1.2 and 2.8% for SOLGEL for Pu and Am respectively. Conclusions : Different transfer rates of Pu and Am from the lung were observed depending on the chemical composition of the oxides and/or the method of their preparation.