Uranium isotopes in Tunisian bottled mineral waters.

(234)U and (238)U activity concentrations and their relative effective doses have been determined in 10 bottled mineral waters in Tunisia. Alpha spectrometry was used as technique to measure uranium isotopes. The obtained isotopic ratio (234)U/(238)U varies between 1.1 and 3 which means that the two isotopes are not in radioactive equilibrium. Measured activity concentration varies between 3.2 and 40 mBq/l for (234)U and between 1.5 and 26.3 mBq/l for (238)U. Effective doses (assuming 2 litres per day of water consumption) coming from this two isotopes are found to vary between 0.16 and 2.02 microSv/a which is lower than the maximum recommended dose level by the WHO.