History of heavy metals told by fish ear bones

Whitehorse – The Yukon Research Centre (YRC) has released a report on heavy metal concentrations found in fish in the Keno Hill mining district. Information collected from fish ear bones can be used to track heavy metal contaminants and potentially determine the success of environmental remediation.

YRC, Access Consulting Group, and Na-cho Nyak Dun First Nation worked with Dr. Norman Halden from the University of Manitoba who developed the technique of fish otolith microchemistry. This technique can determine both contaminant levels as well as life history information on individual fish and populations. Never before used in Yukon, this technique was applied to Arctic Grayling and Slimy Sculpin in the Keno Hill mining district due to the areas long mining history.

“This technique has the potential to provide First Nations, regulators, and other Northerners with robust data to inform land and water decisions in Yukon,” said Dr. Amelie Janin, NSERC Industrial Research Chair, Yukon Research Centre. “This information could advance our understanding of the local ecosystem and become an additional technique in the environmental assessment toolbox.”

This study used Arctic Grayling, a migratory species and Slimy Sculpin, a sedentary species, to measure the concentrations of various heavy metals. Sculpin are known to spend their lifespan in 1 kilometre of river, therefore having the potential of being a good indicator of local conditions. Otoliths were analyzed from fish captured in 2012 and stored by the Department of Fisheries and Oceans Canada. Results proved that grayling could be a potential indicator for zinc contamination, and sculpin a potential indicator for lead.

“Our nation is interested in using research and innovation to assist us in better understanding and managing these impacts to further support us in being successful environmental stewards,” said Chief Simon Mervyn, Na-Cho Nyak Dun First Nation.

Heavy metal contaminants are typically measured through analysis of water, sediment, or fish tissue. This new technique could prove to be more accurate and cost effective than traditional methods in determining long-term exposure trends. It also has potential to track fish movement in and out of contaminated waterways and could be used to meet Federal government requirements (Environmental Effects Monitoring) to study potential impacts on fish populations resulting from industrial activity such as mining.

“Using this technology could lead to a better understanding of contaminated sites and how contaminants fluctuate throughout the year in waterways,” said David Petkovich, Manager, Access Consulting Group. “The otoliths act like a continuous monitoring device that also stores the data for future analysis and review.”

This baseline data can be used to assess evolution of contaminants exposure over the lifespan of the fish species that have been used in this experiment. Additional project information and the results can be found on our website.

This research was facilitated by the Yukon Research Centre with the following project partners: Na-Cho Nyak Dun First Nation, University of Manitoba, Access Consulting Group, Department of Fisheries and Oceans Canada, Yukon Environment, Aboriginal Affairs and Northern Development Canada, and Capstone Mining Corporation. This project was funded by Yukon Fish and Wildlife Enhancement Trust.

The Yukon Research Centre is funded by Government of Yukon’s Department of Education and works in collaboration with the Centre for Northern Innovation in Mining at Yukon College.