Dynamics of plutonium excretion with urine and feces using cases of acute inhalation intake of industrial plutonium compounds as an example

Monitoring internal doses from plutonium is most effectively accomplished by an indirect method based on the interpretation of nuclide activity measurements in excreta using biokinetic and dosimetric models. Currently, Russian Federation regulatory documents utilize the models presented by the International Commission on Radiological Protection in Publications 30, 66, and 67, while the International Commission on Radiological Protection has developed new models and approaches presented in Publications 130, 134, 137, and 141. The aim of this study was to demonstrate the actual dynamics of plutonium excretion in urine and feces in comparison with calculated data upon the intake of plutonium as part of an industrial compound of complex isotopic composition. Materials and Methods : The initial data for the study were the results of determining the activity of plutonium in daily amounts of urine and feces of three workers with acute inhalation intake of industrial plutonium compounds as a result of an emergency. Results and Discussion : For each case, the most suitable scenario (model and set of physicochemical properties of the compound) was selected using the Akaike criterion, depending on the initial data used for the calculation. The calculations were performed based on the results of plutonium activity measurements in urine, the results of plutonium activity measurements in feces, and the results of plutonium activity measurements in urine and feces simultaneously. The statistical analysis performed showed that the choice of the most suitable model and set of physicochemical properties of the compound was determined by the choice of initial data. In one case, none of the models adequately explained the observed levels of plutonium in urine and feces. Conclusion: There is undoubtedly a current lack of knowledge regarding the metabolism of industrial plutonium compounds, including those present at new fuel production sites. This requires extensive research into both the biokinetics and physicochemical properties of industrial plutonium compounds.