Ecotoxicological impacts of the Fundão dam failure in freshwater fish community: Metal bioaccumulation, biochemical, genetic and histopathological effects.

This study investigates the ecotoxicological impacts of the Fundão dam rupture, one of the major environmental disaster that occurred in Brazil and in the world mining industry history, through multi-biomarkers responses and metals bioaccumulation in the fish community of different trophic levels. Specimens of the fishes (omnivorous/herbivorous and carnivorous) were collected along the Doce River channel and its affluent Guandú River, and in different lakes and coastal lagoons adjacent to the river channel, in the Espirito Santo State, Southeast of Brazil. Four sampling collections were carried out over two years (2018 to 2020, during dry and rainy seasons). For both trophic groups the biomarkers responses indicated physiological alterations related to metals exposure and showed strong seasonal variations. The principal component analysis and integrated biomarker response index showed that DNA damage and lipid peroxidation were more associated with dry season 2 (Sep/Oct 2019) and the oxidative damage in proteins, metallothioneins concentration and the activity of superoxide dismutase in the gills showed a greater association with rainy season 2 (Jan/Feb 2020). On the other hand, the enzymes of energy metabolism, catalase and histological damage in the liver and the gills, were more associated with the dry and rainy campaigns of the first year of monitoring. The multivariate approach also suggested a temporal intensification in the bioaccumulation of metals and biological effects in the lacustrine environments. Thus, these results demonstrate that the release of mineral residues from the rupture of the Fundão mine dam affects the health status of the fish from the Doce River basin, provoking metals bioaccumulation, hepatic and branchial damage in the fish besides inducing of enzyme activity related to metal contamination, even four years after the rupture.

Impacts of tailings of Fundão dam (Brazil) rupture on marine fish: Metals bioaccumulation and physiological responses.

This study evaluated the impacts of the mining tailings after the rupture of the Fundão dam on fish communities on the Atlantic Ocean southeast coast. Four sample collections were carried out over two years (2018-2020), in seasonal periods. Omnivorous/herbivorous and carnivorous fish were collected for analysis of metal bioaccumulation, multibiomarkers of environmental contamination and histopathology. Metal bioaccumulation was stronger correlated in carnivorous fish in the dry-2018 collection, besides higher activity of antioxidant enzymes, energy metabolism and higher morphological damage; however, there was less oxidative damage and less metallothioneins induction, and these variables were strongly associated with the wet-2020 collection. In a temporal view, it was possible to observe a reduction in metal levels in fish, except in the mouth of the Doce River. These events can be explained by seasonal natural events, which tend the resuspension and boost metal levels, mainly in the mouth region during the rainy season.