Modeling the quenching of fluorescence from organic matter in Amazonian soils

Autor(es)

Tadini, Amanda Maria ^{[1, 2, 3]} ; Mounier, Stephane ^[3] ; Bastos Pereira Milori, Debora Marcondes ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Chem Sao Carlos, Sao Carlos, SP - Brazil

^[2] EMBRAPA Agr Instrumentat, Sao Carlos, SP - Brazil

^[3] Univ Toulon & Var, Lab MIO, Equipe CEM, CS 60584, F-83041 Toulon 9 - France

• Tipo de documento: Artigo Científico
• Fonte: Science of The Total Environment; v. 698, JAN 1 2020.
• Citações Web of Science: 0

Resumo

Knowledge of the interactions of soil organic matter (SOM) with metal species is important in order to obtain information concerning the fates of the metals in environment, whose reactive functional groups present in SOM can provide high complexation capacity. The aim of this study was to evaluate the interactions involving humic acids (HA) and fulvic acids (FA), extracted from Amazonian soils, with Cu(II) and Al (III) ions, using fluorescence quenching spectroscopy. The obtained results showed that the data for the humic fractions of the Amazonian Spodosols could be fitted with one to one complexation model, which provided the best representation of the changes in fluorescence quenching after addition of Cu(II) or Al (III) ions. It was found that the HA presented fewer complexation sites and lower stability constants, compared to the FA samples. Furthermore, the FA showed selective interaction with the metals, while the HA fraction was less selective and could be associated its homogeneous structure. The results showed that the humic acids required 10 times more carbon in their structures than fulvic acids for complexing a metal atom. This behavior can be associated to the fact that the Fulvic Acid fraction has higher mobility and greater interaction during the profile when compare humic acids. Hence, given the diversity of metals to which the HA has affinity, this soil fraction appears to be mainly responsible for soil fertility, while the FA fraction has higher mobility and greater interaction with water. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/13013-3 - Caracterização das Substâncias Húmicas extraídas de Solos da Região Amazônica
• Beneficiário: Amanda Maria Tadini
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 11/03250-2 - Quantificação e dinâmica do carbono associado a horizontes espódicos profundos de solos da Floresta Amazônica, face a possíveis mudanças climáticas
• Beneficiário: Célia Regina Montes
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/07276-1 - CEPOF - Centro de Pesquisa em Óptica e Fotônica
• Beneficiário: Vanderlei Salvador Bagnato
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 12/51469-6 - Modelling the dynamics of equatorial forest soil deep carbon in changing environments - C-PROFOR
• Beneficiário: Adolpho José Melfi
• Modalidade de apoio: Auxílio à Pesquisa - Temático