Rare earth elements, U and Th in tunnel dusts of São Paulo City, Brazil
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2017
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60 YEARS OF IEA-R1: INTERNATIONAL WORKSHOP ON UTILIZATION OF RESEARCH REACTORS
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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 7 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 Jãnio 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 g g1 and
3:3 – 35:9 g g1 , 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, R.M.; FIGUEIREDO, A.M.G. Rare earth elements, U and Th in tunnel dusts of São Paulo City, Brazil. In: 60 YEARS OF IEA-R1: INTERNATIONAL WORKSHOP ON UTILIZATION OF RESEARCH REACTORS, November 28 - December 01, 2017, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Pesquisas Energéticas e Nucleares, 2017. p. 46-46. Disponível em: http://repositorio.ipen.br/handle/123456789/28743. Acesso em: 26 Mar 2026.
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.