O uso do Radônio como traçador para identificação de descarga de aquíferos ao longo do córrego da Matinha, MG

• Ano de defesa: 2017
• Autor(a) principal: Claudio Jose Chagas
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: ²²²Rn; traçadores; Interconexão de águas subterrâneas-superficiais; Isótopos ambientais; Traçadores radioativos; Isótopos; Tecnologia nuclear; Radon; Águas subterrâneas
• Link de acesso: http://hdl.handle.net/1843/BUBD-AP9PGZ

Within the framework of "Nuclear Techniques" is the use of natural and artificial isotopes as tracers for the study of the environment. The use of natural tracers in hydrology is a very useful tool that has been used in several scenarios. One such tracer is the isotope of radon, 222Rn, a noble gas from natural sources as a consequence of alpha decay of 226Ra. Radon can be found, to a greater or lesser degree, in all groundwater, as well as in soils and rocks from where it exudes into the atmosphere through spaces arising from fissures and or nanopores present. It can emerge into the water bodies by the leaching of water or other liquids through these interstices. In this research, the 222Rn gas diluted naturally by the leaching of the water that infiltrated the soils and rocks of the aquifers was used as a tracer in order to identify sections of discharge of these aquifers along the Stream of Matinha. The study area is about 70 km from Belo Horizonte and is in the city of Itaúna, MG. The Matinha stream is about 2,200 m in length and is part of the network of tributaries of the water reservoir called Serra Azul, in the Juatuba River Basin, MG. The results presented express the studies that occurred between the second half of 2014 and the first half of 2016, in ten campaigns for water sampling, flow and natural gamma radiation measurements. Water samples were collected near the bottom and very close to the thalweg in the watercourse using syringe and or peristaltic suction pump at low flow to avoid gas leakage. The 222Rn analyzes were performed in the field during the collections and in the laboratory of the CDTN Centro de Desenvolvimento da Tecnologia Nuclear, all of which were carried out with the radon detector RAD 7. The flow measurements counted on the use of the fluorescent tracers technique: rhodamine and fluorescein were used for injection at points upstream and downstream of sections with higher 222Rn activities. The fluorimeter used to recover the mass of injected fluorescence tracer was the GGUN FL-30 connected to a notebook so that it could follow the tracer cloud passage. The gamma radiation measurements were fitted with AT6101C detector installed inside a backpack so that they could be scanned along the thalweg and along the banks of the stream. The results showed the presence of significant amounts of the radioisotope in several sections of Matinha stream, which indicates the interconnection between the groundwater and the surface waters. This interconnection with aquifers justifies the increase of the flows found between upstream and downstream of the sections with larger activities of 222Rn, since there were no other superficial contributions along the section studied. The gamma radiation found denotes proximity to the base rock along with the minerals brought by the groundwater and sedimented on the flood surfaces.