Integrated use of antioxidant enzymes and oxidative damage in two fish species to assess pollution in man-made hydroelectric reservoirs

This study investigated the relationship between contaminant body burden and the oxidative stress status of the gills and livers of two wild fish species in the Furnas Hydroelectric Power Station (HPS) reservoir (Minas Gerais, Brazil). Gills and livers presented similar pathways of metals and organochlorine bioaccumulation. During June, organochlorines were associated with lipid peroxidation (LPO), indicating oxidative stress due to the inhibition of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. In the most polluted areas, metal concentrations in the liver were associated with metallothionein. During December, contaminants in the gills and liver were associated with catalase activity and LPO. Aldrin/dieldrin was the contaminant most associated with oxidative damage in the livers of both species. This integrated approach shed light on the relationship between adverse biological effects and bioaccumulation of contaminants inputted by intensive agricultural practices and proved to be a suitable tool for assessing the environmental quality of man-made reservoirs. -- Highlights: ► Metals and organochlorines presented similar pathways of bioaccumulation. ► Organochlorines were associated to enzyme inhibition and LPO in June. ► Metal concentrations were associated to metallothionein in the liver. ► Contaminants were associated to catalase activity and LPO in December. ► Aldrin/Dieldrin was the contaminant more strongly associated to LPO. -- In realistic environmental conditions, a mix of organochlorines and metals inhibited antioxidant defenses, causing oxidative stress in wild fish species