Biokinetics of inhaled 244Cm oxide in the rat: effect of heat treatment at 1150 degrees C.

A study was conducted in rats to determine solubility and subsequent metabolism of an inhaled aerosol of curium treated at high temperatures. Young adult Fischer-344 rats received a single inhalation exposure to one of three monodisperse aerosols of 244Cm2O3 (0.70, 1.3, or 2.6 micron activity median aerodynamic diameter) heat-treated at 1150 degrees C. Animals were maintained individually in metabolism cages for excreta collection and serially sacrificed in groups of two male and two female rats from 2 to 33 days after inhalation exposure. Additionally an injection study with curium citrate was done to define the systemic behavior of Cm in this rat model. The in vivo solubility was inversely related to the aerosol particle size. The relationship of the results of this study to results from other experimental inhalation studies with curium oxide aerosols is discussed, as is the relevance to bioassay interpretation and risk assessment in man.