Voltammetric determination of water complexation capacity of the Turvo Sujo river and of the São Bartolomeu stream sub-basins in Zona da Mata Mineira

Abstract

Humic substances are formed through the decomposition of plants and animal tissues producing complex chemical structures. They are the main organic components of the environment, presenting the ability to complex heavy metals present in natural waters, making these chemical species less toxic than those that are not complexed. Thus, the complexing capacity associated with organic matter has a great environmental impact and can be used as an indicator of water quality. The complexing capacity and the conditional complexing constant of humic substances dissolved in natural waters were determined by voltammetric titration. Appropriate volumes of samples collected in the sub-basins of the Turvo Sujo river and São Bartolomeu stream in the Zona da Mata Mineira were titrated through successive additions of Cu(II) solution. The sub-basins cover the municipalities of Viçosa, Coimbra, Cajuri and Teixeiras and are important for this region in terms of water supply for livestock and agriculture. The values ??of complexing capacities and determined conditional complexing constants showed values ??compatible with those found in the literature for natural waters.