Cumulative Effects of Watershed Disturbances and Run-of-river Dams on Mercury Cycling: Case Study and Recommendations for Environmental Managers.

Run-of-river power plants (ROR) represent the majority of hydroelectric plants worldwide. Their environmental impacts are not well documented and are believed to be limited, particularly regarding the contamination of food webs by methylmercury (MeHg), a neurotoxin. RORs are typically installed in small rivers where combined effects of watershed disturbances with dam construction can complicate environmental management.

Methylmercury in northern pike (Esox lucius) liver and hepatic mitochondria is linked to lipid peroxidation.

Methylmercury (MeHg) readily bioaccumulates and biomagnifies in aquatic food webs leading to elevated concentrations in fish and may thus induce toxicity. Oxidative stress is a suggested effect of MeHg bioaccumulation in fish. However, studies on how MeHg triggers oxidative stress in wild fish are scarce.

Peaks and transient dynamics of ecological and biogeochemical variables following impoundment in boreal reservoirs.

Across the globe, reservoirs represent nearly 10 % of the world's freshwater. River impoundment strongly alters the hydrological regime of aquatic ecosystems which subsequently affect the ecological (e.g.

Enhanced Bioaccumulation and Transfer of Monomethylmercury through Periphytic Biofilms in Benthic Food Webs of a River Affected by Run-of-River Dams.

Run-of-river (ROR) power plants impound limited terrestrial areas compared to traditional hydropower plants with large reservoirs and are assumed to have reduced impacts on mercury cycling. We conducted a study on periphyton and benthic communities from different habitats of the St. Maurice River (Québec, Canada) affected by two ROR power plants and their effect on the bioaccumulation and biomagnification of monomethylmercury (MMHg).