In partnership with the Atikamekw community of Wemotaci, our research aims to better understand how human activities and environmental disturbances can affect mercury (Hg) cycling and methylmercury (MeHg) production in the St. Maurice River (Québec, Canada). This stretch of river has experienced multiple stressors, including the construction of two run-of-river dams (2008), a major wildfire (2010), and ongoing logging activity—factors that can mobilize organic matter and mercury into aquatic systems and potentially increase MeHg formation and transfer through food webs. These processes are particularly relevant for fish consumption, as temporary increases in mercury concentrations have been reported in fish from dam-affected areas, leading to consumption advisories. Through field-based sampling and interdisciplinary approaches, our collaborative work investigates mercury-methylating microbial communities, sediment processes, and bioaccumulation pathways to support a stronger understanding of contaminant dynamics, ecosystem health, and local priorities in this culturally and environmentally important region.

Explore selected recent projects and publications:

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

• A genome catalogue of mercury-methylating bacteria and archaea from sediments of a boreal river facing human disturbances

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

• Effect of cooking temperature on metal concentrations and speciation in fish muscle and seal liver

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