Título:	Dinâmica dos metais em ambiente costeiro contaminado por atividade metalúrgica (Baía de Sepetiba - RJ)
Autor(es):	Tonhá, Myller de Sousa
E-mail do autor:	myllerquimico@gmail.com
Orientador(es):	Garnier, Jeremie
Assunto:	Estuários Mangues Rejeitos metalúrgicos Extrações químicas Isótopos de zinco
Data de publicação:	3-Mai-2021
Data de defesa:	20-Jan-2021
Referência:	TONHÁ, Myller de Sousa. Dinâmica dos metais em ambiente costeiro contaminado por atividade metalúrgica (Baía de Sepetiba - RJ). 2021. 249 f., il. Tese (Doutorado em Geologia)—Universidade de Brasília, Brasília, 2021.
Resumen:	Metallurgical activities are the major sources of metallic contamination for ecosystems capable of effectively change the flow of these elements in the anthroposphere. Once available in the aquatic environment, metals are distributed in several compartments depending on the biogeochemical processes and behaviors at the sediment-water-biota interfaces. Due to the analytical and conceptual difficulties inherent to these processes, it becomes pertinent to develop and implement geochemical tools in an integrated way to trace sources and elucidate processes related to the biogeochemical cycles of metals. An example of analytical innovation is the accurate measurement of isotopic compositions of transition metals, such as the Zn isotopic ratio, which is widely used to trace origin (natural and/or anthropic sources) and the physical-chemical processes in which metals are submitted (precipitation-dissolution, redox reactions, complexation, biological cycle, etc.). An interesting area of study to apply this model of integrated tools in Sepetiba Bay, Rio de Janeiro. This region was heavily impacted between the 1960s and the 1990s by tons of metallurgical material spilled into sediments from successive leaching events and large-scale overflows. The tailings pile was later encapsulated in 2012, but its effects persist nowadays, affecting fragile coastal ecosystems such as mangroves and estuaries. Thereafter, the main objective of this study was to investigate the Zn dynamics (among other metals) in Sepetiba Bay. For this purpose, several geochemical tools have been combined, such as classical tools as multivariate statistics, chemical extractions (simple, sequential, and kinetic), and mineralogical characterization, to more refined tools, including Zn isotopic analysis, X-ray absorption spectroscopy, and Gadolinium anthropogenic. In this sense, samples of hydrometallurgical waste were collected, a transect of sediments along the bay, and a characterization of river inputs. The results showed that the tailings and contaminated sediments had an excess of Zn associated with the most easily extractable fractions, named exchangeable/carbonate fraction. Our study demonstrated that the Zn isotopic signature of the bulk metallurgical wastes did not correspond to the anthropogenic endmember, but it should be assigned to the exchangeable/carbonate fraction. Furthermore, this signature matched with the Zn isotopic signatures found in oysters previous studied, which highlights the applicability of the isotopic tool in biomonitoring investigations. Our study reinforces the interest of using several analytical techniques to trace the contamination routes for the food chain and to elucidate complex environmental issues in the sediment-solution-organism continuum
Unidade Acadêmica:	Instituto de Geociências (IG)
Informações adicionais:	Tese (doutorado)—Universidade de Brasília, Instituto de Geociências, Programa de Pós-Graduação em Geologia, 2021.
Programa de pós-graduação:	Programa de Pós-Graduação em Geologia
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Agência financiadora:	Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) e Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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