Ecotoxicological assessment of water and sediment river samples to evaluate the environmental risks of anthropogenic contamination

Abstract

Several studies have shown the issue of effluent discharges as a source of contamination into waterways. Still, the impact of chemical pollutants on sediment is less well understood, especially from an ecotoxicological perspective, even though it is known that chemicals from industrial processes are frequently released into river systems. Therefore, here we compared water-sediment samples collected in high-anthropogenic urban area and low-anthropogenic peri-urban area. We have used physicochemical parameters, genotoxicity assay, bioindication and acute and surviving chronic toxicity tests - in an integrated biological assessment. Results suggest no acute toxicity related to exposure to samples from both areas. Still, samples collected in the high-anthropogenic urban area were associated with chronic toxicity effects in D. magna. Heavy metals Pb, Cu, and Cr were found in all samples. Even having all averages below the allowed level as determined by CONAMA (Resolution 420-Class 2), the Water Quality Index (WQI) score showed us that samples from high-anthropogenic sites were identified as “Poor,” and samples from low-anthropogenic sites were identified as “Good.” Ephemeroptera, Plecoptera, and Odonata, which are very sensitive organisms, were largely absent in high-anthropogenic areas, showing that it is likely to be associated with WQI. Therefore, careful consideration should be applied to monitoring effluent discharges using predictive tests, considering the environmental risks of sediment contamination and its consequences on the total environment.