Collective dosimetry to distinguish occupational exposure to natural uranium from alimentary uranium background in bioassay measurements.
OBJECTIVE
To assess occupational exposure from uranium bioassay results which are low and impacted by dietary intakes.


METHODS
First, the bioassay results of a group of workers exposed to UO2 were compiled along with results of a control group. A Bayesian approach was developed to account for dietary intakes in the calculation of the committed effective dose from occupational exposure of a group of workers.


RESULTS
Significant differences in uranium bioassay between the exposed and control groups were found establishing an occupational contamination of the exposed group of workers. Because uranium alimentary excretion estimated from the control group is very variable leading to unreliable individual dose assessment, a collective dosimetric approach was chosen. Applying the Bayesian method, all annual committed effective doses for the exposed group were estimated to be below 0.5 mSv with 95% confidence.


CONCLUSIONS
The Bayesian method presented here is well designed to derive best estimate and dose distribution for a group of workers when a contamination is difficult to discriminate from a natural background or alimentary excretion.
IRSN, Laboratoire d'Evaluation de la Dose Interne, IRSN/PRP-HOM/SDI/LEDI , BP 17, 92262 Fontenay-aux-Roses Cedex , France.
Estelle
E
Davesne
Nicolas
N
Blanchin
Eric
E
Chojnacki
Léa
L
Touri
Mariette
M
Ruffin
Eric
E
Blanchardon
Didier
D
Franck
D000465:Algorithms; D001417:Background Radiation; D001499:Bayes Theorem; D001681:Biological Assay; D005243:Feces; D006801:Humans; D016273:Occupational Exposure; D011336:Probability; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D015203:Reproducibility of Results; D014501:Uranium / Q000737:chemistry / Q000493:pharmacokinetics* / Q000652:urine; D014556:Urine
D014501:Uranium
Uranium; alimentary intake; internal dosimetry; variability