Heterogeneity of a (U, Pu) Mixed Oxide Powder at the Level of Inhaled Particles: An EDS Electron Microscopy Study in the Rat

Abstract

Early studies using energy dispersive X-ray spectrometry (EDS) by transmission electron microscopy have shown that mixed (U, Pu) oxide containing 25% of Pu was a homogeneous solid solution, (U, Pu)Ox 96 (Eidison and Meiwhinney, 1983). We have recently published preliminary EDS results on the chemical composition of a (U, Pu)O2 powder containing 5.3% Pu in rat alveolar macrophages after inhalation exposure (Massiot et al., 1996). This inhaled powder appeared heterogeneous, most of the particles being pure UO2 whereas, a few of them were pure PuO2. The aim of this study was to provide semi-quantitative results in order to estimate the range of heterogeneity of this inhaled powder. This was performed on entire alveolar macrophages obtained by pulmonary lavage, a method which provides more information about distribution of particles in the alveolar macrophage population (Massiot et al., 1996) than the usual method, after digestion of the biological matrix (Pairon et al., 1994).