Environmental researchers, Clearwater River Dëne Nation team up to test toxicity of Po-210 in freshwater organisms

Press Release

February 24, 2025

No Canadian water quality guidelines currently exist to protect aquatic life from polonium-210 — a radionuclide that has the potential to accumulate in food webs

Returning for their third year of field work, environmental researchers from Chalk River Laboratories (CRL) travelled to the Clearwater River Dëne Nation (CRDN) in northern Saskatchewan to collect samples needed to test the toxicity of the radionuclide polonium-210 (Po-210) in freshwater environments.

Northern Saskatchewan is home to many of Canada’s uranium mines, where mining activity brings an increased amount of the radionuclide uranium-238 (U-238) from deep in the ground up to the earth’s surface in these areas. As the final radionuclide in U-238’s decay chain, it is possible for Po-210 to concentrate in nearby environments under certain environmental conditions.

Po-210 is an important contributor to the radiation dose that all living organisms receive from naturally occurring radionuclides, and it also has the potential to build up in organisms faster than they can process it, which, consequently, means it has the potential to build up in aquatic food webs. Despite this, no water quality guidelines to protect aquatic life from Po-210 exist in Canada.

“These types of guidelines provide a consistent, science-informed foundation for the government to assess water quality and ensure that the concentration of substances in the water don’t harm the health of the fish, plants, and other organisms that live in it,” explains environmental biologist Matt Bond, who’s working on a research project aiming to better understand at what levels Po-210 can become harmful to life in freshwater environments.

The project is in its third year now, building on two years of work where he and radioecology research technologist Stephanie Walsh studied the presence and behaviour of Po-210 in Canadian regions impacted by uranium mining, working closely and collaboratively with the CRDN. The goal is to gather the data needed to develop Po-210 specific water quality guidelines.

(A student from CRDN gathering environmental samples with CNL Environmental biologist Matt Bond)

Last fall, the researchers and students, teachers, and elders from CRDN collected lake water and over 500 Hyalella azteca — an amphipod crustacean species that lives near the bottom of freshwater bodies of water and feeds on decaying organic matter. Ecologically significant in North America, H. azteca are sensitive to metals and radionuclides, which make them the ideal organism for toxicity testing.

“Living things absorb radionuclides very differently, depending on the environments they exist in. Environmental factors like water chemistry, for example, significantly affect this uptake. And because of this, it was important to collect both local surface water and a wild amphipod culture to be used for the toxicity tests, so that the results would truly reflect the reality,” explains Walsh.

CRL’s Environmental Toxicity Laboratory is specialized in these tests examining how contaminants affect the species’ survival, growth, and reproduction. Currently, the collected H. azteca are acclimating to life in Chalk River, where the toxicity tests can be conducted in a controlled laboratory environment, in water identical to the chemistry that they were collected from.

(A lab culture of H. azteca)

Paul Haynes, a teacher from the Clearwater River Dëne School, says that the years of collaboration between Bond, Walsh, and the students has built meaningful relationships and proven that powerful connections can be made taking a decolonized approach to education.

“This [collaboration] benefits our students, as they’re given world-class opportunities to learn about their changing environment from both a traditional Indigenous perspective and a western scientific approach,” says Haynes. “It provides them the opportunity to not only learn in a hands-on environment, but also play an active role in monitoring the effects of natural resource extraction in their territory.”

This research project is funded by Atomic Energy of Canada Limited’s (AECL) Federal Nuclear Science & Technology (FNST) work plan program, which connects federal organizations, departments, and agencies to the nuclear science expertise and facilities we have at Chalk River Laboratories. Under this program, our researchers carry out projects designed to support the Canadian government’s core responsibilities and priorities across the areas of health, safety and security, energy, and the environment.

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