Quantifying the Impact of Wildfire on MeHg Production

Subarctic regions are undergoing rapid climate change, leading to increased permafrost thaw and more frequent wildfires. These environmental changes significantly impact water quality, which is critical for ecosystems, community health, and food security. Permafrost stores organic material, nutrients, and contaminants such as mercury. When thawed, these substances are released into surrounding water systems, enhancing hydrological connectivity and facilitating contaminant transport. Wildfires further alter hydrological pathways by burning vegetation and organic matter, increasing the release of nutrients and contaminants. Burnt landscapes can accelerate the production of methylmercury (MeHg), a highly toxic and bioaccumulative form of mercury that poses risks to aquatic and terrestrial food webs. This project examines how wildfire affects the production of methylmercury in boreal peatlands by comparing pre and post wildfire water quality data from Scotty Creek Research Center, Northwest Territories Canada. In 2022, the research station and surrounding area were affected by a devastating wildfire. Water quality data at sited examined by Gordon et al. in 2013 were revisited in 2024, allowing for direct comparisons of pH, temperature, dissolved organic carbon (DOC), total mercury, and MeHg concentrations. This study specifically investigates how MeHg concentrations have changed over time and how they correlate with other environmental variables. Additionally, it explores which landcover types exhibit the highest MeHg concentrations and the most significant post-fire changes. Preliminary results indicate a general increase in MeHg concentrations across all landcover types from 2013 to 2024. These findings provide critical insights into how wildfire-driven permafrost thaw influences contaminant dynamics in boreal peatlands. The results of this study will help inform water quality policies and mitigation strategies for managing post-wildfire water quality in northern regions.