This report provides a review of the ICRP (International Commission on Radiological Protection) model for the systemic biokinetics of uranium absorbed to blood, identifies key model parameters that affect urinary excretion, considers uncertainties in values for these parameters, and determines the effect of these uncertainties on dose assessments based on urine measurements. A parallel study of the application of the ICRP respiratory tract model to inhaled DU is reported separately.
Consistent with available human and animal data, the ICRP systemic model predicts rapid urinary excretion of uranium entering blood, about 75% after 1 week and 95% at 1 year, with long-term retention mainly in the skeleton (4% at 1 year, 1% at 20 years).
Following a sensitivity analysis of the ICRP systemic model, uncertainty analysis was confined to values for key parameters: the urinary excretion rate and rates associated with skeletal retention. These uncertainties were considered together and in combination with respiratory tract model uncertainties obtained in the parallel study.