Stable isotope characterization of humic acids and retention capacity for Pb and other heavy metals in the Cananeia-Iguape coastal system (São Paulo - Brazil)

• Grant number: 18/08738-2
• Support Opportunities: Regular Research Grants
• Duration: April 01, 2019 - September 30, 2021
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Christian Millo
• Grantee: Christian Millo
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Elisabete de Santis Braga da Graça Saraiva ; Maria De Nobili ; Stefano Covelli

Abstract

Humic acids are mixtures of organic matter formed during the decay of plants and microbial remains. Humic acids are capable of binding heavy metals through surface adsorption, which makes these organic compounds extremely interesting in environmental studies of estuarine systems impacted by mining activities. The Cananeia-Iguape estuarine system (São Paulo state, Brazil), today under environmental protection, presents moderate contamination by Pb. Recent studies pointed out that the relatively high concentration of Pb in the sediment, linked to past mining activities in the Ribeira River Basin, still constitutes a potential concern for the environment. It is likely that a significant amount of Pb and other heavy metals be bound to humic acids within the sediments. This project aims at (i) identifying the dominant source (marine or terrestrial) of humic acids in the Cananeia-Iguape estuarine system by carbon and nitrogen isotopic analysis; (ii) mapping the spatial abundance of marine and terrestrial humic acids; (iii) using elemental analysis to assess the retention capacity of marine and terrestrial humic acids with respect to Pb and other heavy metals. The results of this project are expected to give insights into the role of humic acids in controlling the dispersion of Pb in estuaries. The project is of potentially high societal relevance, given that the study area is a Biosphere Reserve recognized by UNESCO, hosting numerous traditional fishing communities. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MILLO, CHRISTIAN; BRAVO, CARLO; COVELLI, STEFANO; PAVONI, ELENA; PETRANICH, ELISA; CONTIN, MARCO; DE NOBILI, MARIA; CROSERA, MATTEO; SUTTI, BRUNO OTERO; SILVA, CAMILA DAS MERCES; et al. Metal Binding and Sources of Humic Substances in Recent Sediments from the Cananeia-Iguape Estuarine-Lagoon Complex (South-Eastern Brazil). APPLIED SCIENCES-BASEL, v. 11, n. 18, SEP 2021. (18/08738-2)

BRAVO, CARLO; TONIOLO, ROSANNA; PELLEGRINI, ELISA; MILLO, CHRISTIAN; COVELLI, STEFANO; CONTIN, MARCO; MARTIN-NETO, LADISLAU; DE NOBILI, MARIA. Electron donating properties of humic acids in saltmarsh soils reflect soil geochemical characteristics. Geoderma, v. 419, p. 11-pg., 2022-08-01. (18/08738-2)