Determination of uranium in human hair by acid digestion and FIAS-ICPMS

The content of heavy metals in human hair may serve as an indicator of occu pational or environmental exposure to metal compounds. However, before such exposure can be determined, the level of the element in a "normal" populat ion must be established. The concentration of uranium in human hair was mea sured by flow injection - inductively coupled plasma mass spectrometry (FIA S-ICPMS) after acid digestion of the hair samples. All hair samples were ri nsed in order to remove external contamination prior to the digestion in a 2:1 solution of concentrated nitric acid and 30% hydrogen peroxide. The lim it of detection of the method, for a 50 mg hair sample, was 0.015 mug/g, ma inly due to the presence of impurities in the hydrogen peroxide. The range of uranium concentration in the initial test group was found to be 0.01-0.1 8 mug/g. The mean and median values of the entire study population were 0.0 62 and 0.050 mug U/g hair, respectively. Differences between the following sub-populations: male and female, smokers and non-smokers and people below and above 45 years of age were examined. The only statistically significant difference was found in the latter group (p = 0.03).