Association of different biomarkers in vivo and in vitro to assess water quality in Ilha River, Southern Brazil.

The Ilha River is one of the main tributaries of the Sinos River, consequently contributing to its ecological impact. The present study aimed to associate the use of different biomarkers in vitro and in vivo to assess the water quality of three points along the Ilha River during 2019. For this purpose, water samples were collected at the source and mouth of the river, and in an intermediate section. In the laboratory, samples were used for in vitro toxicity tests with the V79 cell line, in which we evaluated the protein content and mitochondrial activity through the MTT assay. The results indicated a possible disruption in cellular mitochondrial activity. Acute toxicity tests were also carried out in Danio rerio and Daphnia magna , and a chronic toxicity test was performed in C. elegans. No significant differences were observed in the antioxidant defense enzymes (SOD, CAT and GPx); however, the point of greatest agricultural impact inhibited the activity of muscle AChE in zebrafish. All samples delayed the development of C. elegans , characterizing toxicity. Phosphorus was above the limit established by Brazilian legislation at the three sampling points in two of the three collections, indicating the probable presence of agricultural components in the water. The results alert to the need for the association of different bioindicators and, whenever possible, the use of chronic toxicity tests for the best environmental diagnosis. [ABSTRACT FROM AUTHOR]