Natural Radioactivity in Mineral Spring Waters of a Highly Radioactive Region of Brazil and Consequent Population Doses

Concentration levels of 226 Ra, 228 Ra and 210 Pb have been analysed in most of the mineral spring waters available in the Aguas da Prata region. Concentrations ranging from < 2.2 TO 2106 MBQ.L −1 and from < 3.7 TO 23.1 MBQ.L −1 were observed for 226 Ra and 228 Ra, respectively. For 210 Pb the geometric mean varied from 8.4 to 1040 mBq.l −1 . Dose calculations were performed in order to evaluate the relative importance of such radionuclides to the radiation exposure due to the ingestion of these waters. Based upon measured concentrations, committed effective doses up to 1.1 mSv.y −1 , 0.55 mSv.y −1 and 10 −2 mSv.y −1 were observed for 210 Pb, 226 Ra and 228 Ra, respectively. These results show that 210 Pb and 226 Ra are the main contributors to radiation exposure