Uranium isotopes in Tunisian bottled mineral waters.

234U and 238U 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 234U/238U 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 40mBq/l for 234U and between 1.5 and 26.3mBq/l for 238U. Effective doses (assuming 2litres per day of water consumption) coming from this two isotopes are found to vary between 0.16 and 2.02μSv/a which is lower than the maximum recommended dose level by the WHO.