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

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