Rare earth elements, U and Th in tunnel dusts of São Paulo City, Brazil
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2017
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INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE
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Resumo
São Paulo is one of the most populated cities in the world, with about 20 million inhabitants in its metropolitan
area, more than 12 million motor vehicles and intense industrial activity. Given its importance as a major urban
center in South America and the lack of information concerning urban dust composition, the present study
aimed to determine rare earth elements (REEs), U and Th mass fractions in tunnel dust, collected in the Jânio
Quadros Tunnel, and to assess their possible sources. The study of REEs distribution in urban environments has
become of interest over the last decades, due to the increasing industrial use of these elements. The REEs, that
are as common as the most familiar metals, are found in metallurgical additives, fluid cracking catalysts and
automobile converter catalysts, among other applications. In this study, which employed Instrumental Neutron
Activation Analysis (INAA) as analytical technique, the mass fractions of eight REEs were determined and
normalized to the chondrite concentration values. The results showed that major concentrations were found for
light REEs, following the sequence Ce > La > Nd > Sm > Yb > Eu > Tb > Lu. The pattern of the results pointed
to a natural origin for these elements. Regarding U and Th concentrations, the results varied between 1.0 – 9.4
μg g-1 and 3.3 – 35.9 μg g-1, respectively. Since there is almost no information about the concentration of these
elements in this kind of matrix in São Paulo city, these data are important to support further investigations.
Como referenciar
NORY, RENATA M.; FIGUEIREDO, ANA M.G. Rare earth elements, U and Th in tunnel dusts of São Paulo City, Brazil. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017. Disponível em: http://repositorio.ipen.br/handle/123456789/28264. Acesso em: 10 May 2024.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.