Dose assessment to members of the pulic in Tunisia from intakes of some naturally occurring radionuclides in bottled mineral water

Total α- and β- as well as radium isotopes (226Ra, 228Ra) and uranium isotopes (234U, 238U) activity concentrations were determined in six most popular Tunisian bottled mineral waters samples. Total alpha/beta activity was measured by background gas-flow proportional counting system, and the activity concentrations of uranium were studied by radiochemical separation procedures followed by alpha spectrometry and that of radium isotopes by gamma-ray spectrometry. The total-a activity ranged from 48 to 94 mBq L−1 and the total-b activity between 45 and 430 mBq L−1. The activity concentrations of 238U, 234U, 226Ra and 228Ra in water samples varied in range 3.3 - 22.5 mBq.L−1, 4.0 - 34.2 mBq L−1, 2.0 - 67.0 mBq L−1 and 2.0 - 30.2 mBq L−1, respectively. These values are comparable with those reported for many other countries in the world for different types of water. The 234U/238U activity ratio were found to be higher than 1 in all cases. Based on the activity concentration results obtained in this study, the estimated annual ingestion dose rates for three different age groups (< 1 year, 7-12 years, and > 17 years) due to the ingestion of radium and uranium isotopes through drinking water are lower than the limit of intake prescribed by WHO. The annual doses exceed the recommended value of 0.1 mSv y-1 in one case for age group < 1 year. According Based on the activity concentration results obtained in this study, the estimated annual ingestion dose rates for three different age groups (< 1 year, 7-12 years, and > 17 years) due to the ingestion of radium and uranium isotopes through drinking water are lower than the limit of intake prescribed by WHO. The annual doses exceed the recommended value of 0.1 mSv y-1 in one case for age group < 1 year.