Past Project

Mercury in Trout

Human activities, such as combustion of fossil fuels, industrial processes, and mining, add notable amounts of mercury to the atmosphere. Mercury is also released into the atmosphere via natural pathways, such as volcanic eruptions and ocean volatilization. However, as of 2015, human activities account for over 2000 tonne of mercury emitted annually. Because of human contributions of mercury to the atmosphere, levels are now ~500% above background. More atmospheric mercury leads to more mercury deposited to aquatic systems. While mercury is a common element present in very low amounts in most aquatic systems, even very small increases can have harmful effects on organisms, especially predators. When mercury is introduced to freshwater, it can be transformed into its more bioavailable form, methylmercury through methylation. Methylation occurs via bacteria and other microorganisms and is dependent on specific physical and chemical conditions of the body of water. Methylmercury is absorbed by aquatic organisms through diet and enters the bloodstream where it accumulates in muscle tissue and poses a threat to the central nervous system. High concentrations of methylmercury in tissues may result in decreased reproductive success, inability to avoid predators, malnourishment, and sensitivity to environmental stressors.

This collaborative research with university and provincial government (Natural Resource & Energy Development and Health) partners examines mercury in brook trout (Salvelinus fontinalis) in remote lakes across the province of New Brunswick. Brook trout are one of the commonest fish targeted by resident anglers in the maritime provinces of Canada. We aim to build upon the baseline dataset of a 1994 trout-mercury survey by re-sampling 20 of 35 lakes. For each strategically selected study lake, up to seven brook trout ranging from 20-40 cm in size will be collected. The total mercury content of muscle tissue will then be measured with partners at Universite de Moncton.

Our 2023 findings will be compared to the 1994 provincial survey to determine trajectories of mercury within brook trout from New Brunswick lakes. Findings will address the risk of mercury in the aquatic environment and will also have implications for global pollutant monitoring and human health.

 
 

Collaborators on this project include

We also acknowledge Acadian Timber and J.D. Irving, Limited for granting access to several study lakes within their land holdings. Funding for this study was provided by New Brunswick Wildlife Trust Fund and Mount Allison’s Independent Student Research Grant program.