Temporal analysis of eutrophication and water toxicity in the Jundiaí Mirim river basin, São Paulo State, Brazil

Natural and anthropogenic pressures generate numerous negative impacts on the physical and biotic environment of the watersheds. Such impacts cause risks to the water security of the basins, due to the increase in consumption, concentration of pollutants and siltation of water bodies. The objective of this research was to perform a temporal analysis of eutrophication and water toxicity in the Jundiaí Mirim River Basin (BHJM), in the state of São Paulo, Brazil. The methodology was based on the analysis of data published in public reports, including the Trophic State Index (TSI) and the Quality Index for the Protection of Aquatic Life (QIAF), in the period from 2017 to 2022. The results indicate eutrophication along the water bodies of the basin, inferring about the discharge of domestic sewage and carried fertilizers. The QIAF was influenced by high concentrations of Lead and Mercury, above those recommended for Class 1 rivers by the Brazilian federal legislation.