Snowshoe hares near the now closed Giant Mine outside of Yellowknife have elevated levels of arsenic. Photo: Denali National Park and Preserve, via Flickr
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Even though it was closed decades ago, the Giant Mine on the outskirts of Yellowknife has left a long environmental legacy.
Elevated arsenic levels have also been reported in soil, vegetation and fish around Yellowknife, but we knew little about how it has affected the health of the small mammals that live in the area.
Many of these fur-bearing animals are still being trapped for their pelts and for food, so knowing their arsenic levels is also important for human health.
Weak bones
Small mammals can serve as sentinels for environmental contamination. Snowshoe hares (Lepus americanus) live in a relatively small area and eat soil, so they are likely to accumulate higher levels of arsenic and other trace metals from the environment.
Exposure to elevated levels of arsenic can cause damage to the liver and other organs. And cadmium, a toxic metal and another byproduct of the gold extraction process, can replace calcium in the bones, leading to bone deformities and weakness.
When we measured arsenic and cadmium levels in hares living within two kilometres of the Giant Mine and compared them to hares living about 20 kilometres away from Yellowknife, the results were striking.
The arsenic levels in the guts of snowshoe hares living near the Giant Mine were 20-50 times greater than those living away from it. We also saw higher concentrations of arsenic in the organs and nails of the Giant Mine hares.
Cadmium levels were also higher but the difference wasn’t as marked. Hares from both locations had weaker bones and showed signs of osteoporosis, probably due to chronic exposure to cadmium.
This chronic exposure to elevated levels of arsenic and cadmium may explain why snowshoe hares living near the Giant Mine are in poor health.
Wildlife living in metal contaminated areas in other parts of the world have also shown problems with reproduction, osteoporosis, neurological damage and chronic metabolic disease. But in Canada, it’s the first time we’ve seen small wild mammals with chronic arsenic poisoning.
The high levels of pollutants could compromise the long-term survival of the snowshoe hare and other small mammals in the Yellowknife area.
The high arsenic and cadmium burden in hares could have consequences for other animals that prey on them, such as foxes, wolves or other carnivorous mammals, and for the people who hunt them
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Here at The Narwhal, we don’t use profit, awards or pageviews to measure success. The thing that matters most is real-world impact — evidence that our reporting influenced citizens to hold power to account and pushed policymakers to do better.
And in 2024, our stories were raised in legislatures across the country and cited by citizens in their petitions and letters to politicians.
In Alberta, our reporting revealed Premier Danielle Smith made false statements about the controversial renewables pause. In Manitoba, we proved that officials failed to formally inspect a leaky pipeline for years. And our investigations on a leaked recording of TC Energy executives were called “the most important Canadian political story of the year.”
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The high arsenic and cadmium burden in hares could have consequences for other animals that prey on them, such as foxes, wolves or other carnivorous mammals, and 
