The Statistical Distribution of Assessed Actinide Intakes

Over 200 cases of actinide intake, occurring over the last 25 years, have been re-assessed. Cases were selected for which the intake date was known, there was both urine and faecal data and there was negligible interference from earlier intakes. The IMBA software was used to obtain a best fit to the data and establish an estimate of intake for each case. It is found that the magnitudes of the intakes are very well fitted by a lognormal distribution and that this fit extends over 4 orders-of-magnitude in intake. Therefore small intakes are much more likely than large ones. This fact is of significance in the assessment of routine monitoring results and in dose assessments for epidemiology. The distribution of intakes found here could be used as a prior distribution in a Bayesian analysis.