Absorption of plutonium compounds in the respiratory tract

Abstract

In order to optimise the monitoring of potentially exposed workers, it is desirableto determine specific values of absorption for the compounds handled. Thisstudy derives specific values of absorption rates for different chemical forms ofplutonium from in vitro and animal (monkeys, dogs, mice, rats) experiments,and from human contamination cases. Different published experimental datahave been reinterpreted here to derive values for the absorption parameters,fr,sr andss, used in the human respiratory tract model currently adopted by the InternationalCommission on Radiological Protection (ICRP). The consequences of the useof these values were investigated by calculating related committed effectivedoses per unit intake. Average and median estimates were calculated forfr,sr, andss for each plutonium compound, that can be used as default values for specific chemicalforms instead of the current reference types. Nevertheless, it was shown that the use of thecurrent ICRP reference absorption types provides reasonable approximations.Moreover, this work provides estimates of the variability in pulmonary absorption and,therefore, facilitates analyses of the uncertainties associated with assessments, eitherfrom bioassay measurements or from prospective calculations, of intake and dose.