A Model for Scaling the Results of U Excretion Rate Studies in Beagle Dogs to Man

Abstract

A biokinetic model was used to simulate retention and excretion of two forms of U: ammonium diuranate (ADU), a relatively soluble form, and U3O8, a relatively insoluble form. These two U forms represent those most likely to be encountered in the U milling industry. The simulation model was compared with results from a study of aerosols of commercial refined U ore inhaled by laboratory animals. Beagle dogs were exposed by inhalation to ADU aerosols to achieve a median initial body burden of 0.058 mg U kg-1 body weight (within a range of 0.016 to 0.64 mg U kg-1), or to U3O8 aerosols to achieve a median retained body burden of 0.28 mg U kg-1 (0.030-0.81 mg U kg-1). The simulation model accurately described the accumulation of nephrotoxic concentrations of U in kidneys of animals exposed to ADU. Very small fractions of the initial body burden of U3O8 were translocated to kidney, and these fractions were overestimated by the model. The model showed general agreement with results of other laboratory animal studies and with available information from human exposures to ADU, UF6, or U3O8.