Radiological quality of mineral waters bottled in Tunisia

There are approximately 60 natural water springs in Tunisia, but only 10 of them, mostly in the north, are legally authorized to be sold for bottled mineral water. The object of this study is to determine the radiological content of the mineral waters bottled in Tunisia by calculating the annual effective dose resulting from ingestion of the natural radionuclides in these waters. The results show that radioactivity is relatively low in the Tunisian mineral waters and is due essentially to uranium and radium picked up as the water passes through the deep rocks. Levels measured range from 3.3 to 2.5 mBq/L for 238U and from 4.0 to 34.2 mBq/L for 234U. Radium levels range from 2.0 to 67.0 mBq/L for 226Ra and from 2.0 to 30.2 mBq/L for 228Ra. These levels are lower than those measured in many other regions over the world. For daily mineral water consumption over one year, the estimated effective dose level varies between 0.006 and 0.091 mSvfor an adult and between 0.008 and 0.107 mSvfor a 5-year old child. These results do not present a public health risk in Tunisia. This investigation enabled us to assess the contribution of bottled water to radiological exposure of natural origins.