How to Reduce the Uncertainties of Committed Dose Derived from Urinary Uranium Measurements: Investigation of New Protocols using ICP-MS

Abstract

For individual monitoring, the amount of uranium in urine is routinely determined, after purification, using alpha spectrometry. To reach the lower detectable activity level derived from the ICRP recommendations this technique has two main drawbacks : the long counting times required and the need to use large volumes of sample. Typically, one litre of urine is collected during a twenty four hour period to measure uranium. The estimated doses based on such measurements need to be taken with caution due to the large uncertainties on the representativeness of urine samples. Smaller urine volumes collected with a regular frequency would allow these uncertainties to be reduced. The present work focuses on the applicability of Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) to achieve this aim. The abilities of this technique, which exhibits very low detection limits for uranium, are investigated on small samples regarding compliance with the legal requirement and also the ease of use for individual monitoring.