Small animals near Giant Mine carry the effects of long term arsenic exposure in their brains and eyes, a recent study suggests. 

Targeting some squirrels and muskrats at varying distances from Giant Mine, researchers have produced a preliminary study suggesting arsenic has impacted the animals’ brains and eyes. The research has recently appeared in science journals Chemosphere, and The Science of the Total Environment.

“What I do know for sure based on the preliminary study we just conducted, the animals around Yellowknife are definitely going through some level of environmental stress,” University of Saskatchewan Professor Solomon Amuno said about the study, which also featured researchers from his school and McGill University.

“That is definitely showing impact on their visual (system) and their brain.”

Muskrats in the Giant Mine are appear to be showing signs of arsenic exposure.
NNSL file photo

A similar study also showed poor health among hares in the vicinity of Giant Mine in 2017.

Work on this particular research was conducted from 2018 into 2019, said Amuno. There were three sampling locations, with one each at roughly two kilometres, 20 kilometres and 50 to 120 kilometres. Researchers collected 10 animals from each site. 

The findings concerning the nails of animals are good indicators of arsenic exposure over a long period of time, said Amuno. 

“The evidence definitely confirms that the animals for sure have been exposed to high levels of arsenic in their environment over a long time.”

From analysis of stomach content, the research also confirmed that the animals are also exposed to arsenic in their diets. 

This is a trend seen only in the animals closer to the mine site, and is also reflecting the nail findings, said Amuno. 

“When animals are exposed to high levels of arsenic of that range, they’re at risk of different kinds of diseases. This could range from organ damage, even to death,” he said. 

Brain damage can manifest in an animal’s retina, said Amuno. All the animals collected in the near vicinity of Giant Mine site showed signs of eye damage, such as cataracts and reduction of retina layers.

That all suggests brain damage, but Amuno cautioned against drawing conclusions. The samples were extremely limited and arsenic may not be the only factor. 

“We’re very careful not to draw any conclusions from what we’ve seen. (However,) arsenic for sure may play a very key role in this because only animals captured in the arsenic affected area show this significant eye damage,” he said. 

This was more prominent in the muskrats, he added, explaining eye damage like this is rare outside of the laboratory.

“We’ve never really seen this significant kind of eye damage in the wild,” said Amuno, adding more research is needed to get to the bottom of these circumstances.

There was also evidence of brain shrinkage in the arsenic-affected areas, particularly among muskrats, he said. Again, it’s unclear if there are other factors at play.

Squirrels, meanwhile, showed more extensive changes, particularly as their core brain structures and cortex shrank. 

“The idea of this research is not to freak anybody out,” he said, noting it is a preliminary study, and does not aim to draw any conclusions.

NWT Chief Public Health Officer Dr. Kami Kandola stated the study has no direct implications on public health.

“It would be difficult to translate the impact of arsenic or cadmium exposure and the observed adverse health effects on small animals to humans,” stated Kandola. 

Further, she stated, the study reviewed arsenic levels in the nails of muskrats and stomach content of squirrels. This did not include arsenic or cadmium levels in the animals’ meat.

“Hence, the study was not useful for assessing the risk to people who may hunt small animals for personal consumption,” she stated.

Nick Pearce

Nick Pearce is a writer and reporter in Yellowknife, looking for unique stories on the environment and people that make up the North. He's a graduate of Queen's University, where he studied Global Development...

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