Analysis of potentially toxic elements in waters and sediments of the Sorocaba River following its environmental recovery

Abstract

The presence of potentially toxic elements (PTEs) in aquatic environments deserves attention, mainly due to the adverse effects they can have on water quality and ecological and human health. In this context, this study aimed to analyze and evaluate PTEs in waters and sediments of the Sorocaba River at different sampling points distributed throughout its urban extension. Element quantifications were performed by microwave plasma atomic emission spectrometry (MP-AES), after acid digestion of the samples. The PTEs Al, Fe, and Mn were above the maximum value allowed (MVA) by Brazilian legislation for waters, and As, Cu, and Cr was above the MVA for sediments. Based on the aforementioned results as well as the assessment of land use around the sampled sites, it is possible to demonstrate that the high concentrations of PTEs are probably caused and/or intensified by human activities. Additionally, the applied Enrichment Factor index (EF) indicated moderate anthropogenic enrichment for As, Cr, Cu, and Zn in three points in the study area, and very high for Zn in one location. This investigation alerts us to the parameters of attention that must be investigated in the ecosystem since the Sorocaba River has already been subjected to a program to clean up its waters.