Tackling Mercury Risks in the Mackenzie River Basin

1. Why is mercury contamination in the Mackenzie River Basin an important issue?

The Mackenzie River Basin supports freshwater, coastal, and marine food webs that northern communities depend on for food security. The Basin drains an enormous geographic area, meaning local conditions can be influenced by far-away stressors such as atmospheric deposition, wildfires, etc.

Mercury levels are increasing in some regions due to industrial activity and climate-driven mobilization of mercury. People who rely on fish and country foods are more exposed to mercury and therefore more vulnerable to changes in mercury levels. Sensitive species, including key food fish, accumulate mercury at levels that can affect health and ecosystem integrity.

2. How does this project help us understand the real risks that mercury poses to people and ecosystems in the North?

Our chosen models (Bayesian Network model) are able to integrate multiple mercury sources (permafrost thaw, erosion, deposition) to identify which ones have a stronger relationship to higher mercury levels. They also allow for scenario testing under future climate conditions, such as increased rainfall intensity, thaw slumps, or coastal erosion. The models combine Western scientific datasets with community-informed indicators, offering a more complete picture of risk. Developing community-specific models, such as the ones for Tuktoyaktuk, can improve relevance for people’s lived realities.

The end products of our research project will provide accessible, interactive models that visualize exposure pathways for fish, wildlife, and human consumers. The outputs can aid policy and decision-makers in prioritizing mitigation, monitoring, or adaptation strategies.

3. How can environmental changes in the Arctic influence the way mercury moves through freshwater systems and into fish?

Thawing permafrost releases previously stored mercury into rivers and lakes. More frequent and intense rainfall events, flooding, and riverbank erosion can mobilize mercury-rich soils and redirect where mercury accumulates and enters freshwater food webs. Wildfires, which are increasing with warming, release mercury stored in vegetation and soils into the atmosphere. Warmer waters can shift fish growth rates, restructure food webs, and alter mercury bioaccumulation patterns by changing microbial activity and the conditions that promote mercury methylation.

4. What are the biggest knowledge gaps this project is trying to fill?

Some of the knowledge gaps that this project addresses are:

• Which of the different mercury sources (atmospheric, permafrost thaw, erosion, waste-related) are relatively most important under current and future conditions.
• How can we best integrate Indigenous Knowledge indicators of ecosystem health into probabilistic risk models. This involves identifying the community-specific exposure pathways that influence mercury risk estimates, including cultural, dietary, and economic variables.

5. How are Indigenous communities being involved in the project?

Community engagement is a key component of this project. Community interviews (e.g., through the NUNA project) provide social, cultural, and ecological indicators for the models. Stakeholder consultations in Tuktoyaktuk are planned to validate model structure and ensure relevance. Indicators such as water vitality, fish texture, taste, and observed abnormalities come directly from community knowledge. Co-development of the community-specific model ensures that local priorities shape the research questions. Communities help define what “healthy ecosystems” and “safe foods” mean in locally grounded terms.

6. What role does Indigenous Knowledge play in understanding long-term environmental change in the basin?

Indigenous Knowledge captures multi-generational observations of fish, water, weather, and harvesting conditions and contextualizes environmental changes within cultural, seasonal, and land-use patterns. It helps identify meaningful model variables that Western science might overlook (e.g., fish health markers based on Indigenous ecological knowledge) and strengthens interpretations of scientific datasets by providing local explanations for observed trends. Besides, Indigenous Knowledge informs spatial context, including where people harvest and how landscapes are changing.

7. How does the project ensure that research outcomes are relevant and useful for communities who depend on fish for food?

Community input is built directly into the model through interviews, Indigenous ecological knowledge indicators, and consultations. Outputs will be shared in plain-language formats and through user-friendly interactive visualizations that enable communities to explore how climate change or local development may affect food safety.

Community priorities (e.g., coastline stability, water quality, fish texture) are foundational parts of the modeling framework.