No abstract

For several decades, Northern Québec has been exploited by mining companies for its mineral resources, yet, research documenting the effects of toxic stress on fish health in subarctic environments remains limited. In this study, one lake directly affected by mining activities in the Schefferville area, two lakes close to mining facilities in the Fermont and Schefferville areas, and one reference lake were sampled for water, sediment and fish. Our results suggest that manganese bioaccumulation induced an oxidative stress in Catostominæ, as demonstrated by the positive relationships between manganese concentrations and catalase activity and 8-hydroxy-2’deoxyguanosine concentrations, as well as the negative relationship with glutathione peroxidase activity (both catalase and glutathione peroxidase activities being biomarkers of antioxidant capacities and 8-hydroxy-2’deoxyguanosine an indicator of DNA oxidative damage). Similarly, selenium bioaccumulation was positively correlated with 8-hydroxy-2’deoxyguanosine concentrations in Salmoninæ. These results suggest a prooxidant role of excess selenium and manganese, and highlight the interspecific variability of fish responses to contaminated areas around historical and current iron ore mining operations.