Impact of 210PB from Osamu Utsumi mine on sediment of rivers in Caldas Region, Minas Gerais

The Osamu Utsumi Mine of the Industrias Nucleares do Brasil (INB) is located in Caldas region, Minas Gerais, Brazil. It is a uranium mining and is in process of shutdown, decommissioning stage. CDTN/CNEN (Nuclear Technology Development Center, sponsored by Brazilian Commission for Nuclear Energy) is participating in this decommission step. One contribution will be the characterization of the environmental liability, determining the impact on the environment caused by mining activities. Several radionuclides are being analysed in diversified matrixes, however, this paper is about determination of 210Pb in sediment of rivers. One reason to analyse 210Pb is due to its long half-life (22.3 years) that may point out the carrier of 222Rn, 226Ra, 228Ra, even U, in the region. Besides, it may be used to date sediment. The methodology applied to determine the 210Pb activity in sediment was gamma spectrometry that was established at CDTN during the development of this study. The results confirmed the impact of the uranium mining on the environment. (author)