A Bacia de Juatuba, situada a cerca de 60 km de Belo Horizonte, tem sido utilizada como um laboratório de diversos estudos hidrossedimentológicos há diversos anos, em projetos de pesquisas que muitas vezes envolvem o uso de traçadores naturais, fluorescentes e radioativos. Neste trabalho, o radônio foi utilizado como traçador para investigar a ocorrência de seções de descarga na Bacia de Juatuba. Para análises das concentrações de atividade do radônio nas amostras de águas coletadas foi utilizado o equipamento RAD 7. Foram encontradas seções com concentrações de atividade de radônio muito acima da média do córrego em estudo. Variações de vazões obtidas com o uso de traçadores fluorescentes e um fluorímetro ratificam o indicativo da existência de seções de descarga no local.

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For thousands of years, water has been the focus of experimentation toward solving the challenges associated with human water supply, navigation, irrigation, and sanitation. The use of tracers to study water resources is an efficient approach that can facilitate the modeling of many hydrological scenarios. The goal of this paper is to show results of research that tracked the presence of Rn-222, a natural tracer, in the surface waters of a small watercourse in southeastern part of Brazil. RAD 7, which is an electronic and portable radon detector, was the main instrument used in this survey. We analyzed 117 water samples and converted the radon activity results to effective radiation doses with respect to the hypothetical human consumption of these waters. We also analyzed the sediments of the watercourse. The obtained data showed that the radon activity in the studied waters varies between 0.52-76.96 Bq/m3. We determined the effective dose of all samples to be less than 1 mSv y−1, and its consumption to present no risk to human health. The existence of connections between surface and subsurface waters in the stream is possible, and radon peaks may indicate the existence of discharge zones into the surface water body.

One of the dilemmas that characterizes the end of active service of small hydroelectric plants (SHPs) is regarding the destination of the dams. This is the case of the Pandeiros SHP, located in the state of Minas Gerais, Brazil. Several alternatives are being considered to make its decommissioning feasible, such as opening the bottom discharge gate and removing the reservoir containment dike. However, in a review of recent research in the basin, more than 200 active gullies were found upstream of the dam, contributing to the silting up of the reservoir and of the Pantanal Mineiro, an extensive wetland downstream of the SHP that is vital to the biodiversity of the region. Following a worldwide movement to reuse such structures, periodic dredging of part of the sediment retained in the reservoir is proposed, converting it into a trap to reduce the silting of the wetland by the upstream sediment, in addition to the creation of a reserve volume of water needed for agriculture and human consumption.