Metal Binding and Sources of Humic Substances in Recent Sediments from the Cananeia-Iguape Estuarine-Lagoon Complex (South-Eastern Brazil)

Author(s):Show less -

Millo, Christian ^[1] ; Bravo, Carlo ^[2] ; Covelli, Stefano ^[3] ; Pavoni, Elena ^[3] ; Petranich, Elisa ^[3] ; Contin, Marco ^[2] ; De Nobili, Maria ^[2] ; Crosera, Matteo ^[4] ; Sutti, Bruno Otero ^[1] ; Silva, Camila das Merces ^[1] ; Braga, Elisabete de Santis ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Oceanog, Praca Oceanog 191, BR-05508120 Sao Paulo - Brazil

^[2] Univ Udine, Dipartimento Sci Agroalimentari Ambientali & Anim, Via Sci 206, I-33100 Udine - Italy

^[3] Univ Trieste, Dipartimento Matemat & Geosci, Via Weiss 2, I-34128 Trieste - Italy

^[4] Univ Trieste, Dipartimento Sci Chim & Farmaceut, Via Licio Giorgieri 1, I-34127 Trieste - Italy

• Document type: Journal article
• Source: APPLIED SCIENCES-BASEL; v. 11, n. 18 SEP 2021.
• Web of Science Citations: 0

Abstract

The Cananeia-Iguape estuarine-lagoon complex (Sao Paulo state, Brazil) is a natural laboratory to study metal binding by humic substances (HS) in subtropical settings. This transitional environment is evolving into a freshwater environment due to water input from the Ribeira River, funneled through the Valo Grande Canal (Iguape). Past mining activities in the Ribeira River basin and maritime traffic are suspected to be potential sources of trace metals in the system. In this study, the trace metal contents of Free Humic Acids (FHA), Bound Humic Acids (BHA), and Fulvic Acids (FA) extracted from sedimentary organic matter were investigated. Moreover, the sources of HS were traced using their stable carbon isotope compositions and C/N ratios. The results suggested a mixed marine-terrestrial source of FHA, BHA, and FA. Copper and Cr were the most abundant trace metals bound to HS. On average, Cu showed concentrations of 176, 115, and 37.9 mu g g(-1) in FHA, BHA, and FA, respectively, whereas Cr showed average concentrations of 47.4, 86.3, and 43.9 mu g g(-1) in FHA, BHA, and FA, respectively. Marine FHA showed the highest binding capacity for trace metals, whereas terrestrial FA derived from the decay of mangrove organic matter showed the lowest binding capacity. (AU)

• FAPESP's process: 18/08738-2 - Stable isotope characterization of humic acids and retention capacity for Pb and other heavy metals in the Cananeia-Iguape coastal system (São Paulo - Brazil)
• Grantee: Christian Millo
• Support Opportunities: Regular Research Grants