A group of researchers has discovered elevated levels of two toxins 鈥� arsenic and cadmium 鈥� in a small sample of snowshoe hares in the Yellowknife area.
Solomon Amuno and Som Niyogi, wildlife toxicology researchers at the University of Saskatchewan, compared the health of 10 snowshoe hares within two kilometers of Giant Mine to that of 10 snowshoe hares within 20 kilometres of the site.
鈥淲e generally came to the conclusion that the animals in the Giant Mine area are in poorer health condition,鈥� said Amuno, who has worked on similar studies in Nunavut.
鈥淲hat we have tried to generate through our study is to provide useful data that we think the responsible government authorities or agencies could use 鈥� to establish any criteria for arsenic concentration in animal tissues.鈥�
For their study, the researchers examined arsenic and cadmium levels in the bones, kidney, liver and stomach of the small mammals.
Arsenic can occur naturally in the environment, according to a GNWT fact sheet, however inorganic forms like those produced by Giant Mine can be toxic at high levels of exposure.
Cadmium is another highly toxic element that can cause adverse health effects and has been found in the Arctic, said Niyogi. It can be released into the air through human activities like smelting, according to Environment and Climate Change Canada.
The researchers鈥� study found stomach contents of snowshoe hares around Giant Mine had the highest concentration of toxins, with arsenic levels up to 17 to 49 times higher than in hares captured 20 kilometres away.
Arsenic levels were three to 12 times higher in the livers of snowshoe hares found by the mine site compared to those within 20 kilometres, said Amuno.
鈥淔or the kidney we found also a similar trend,鈥� he said, explaining those results were four to 14 times higher in hares at the mine compared to those found further away.
鈥淭hat suggests that the animals from the Giant Mine area seem to be exposed to high levels of arsenic in their diet,鈥� said Amuno.
All of the hares sampled showed signs of osteoporosis, meaning their bones were susceptible to fracture and in poor condition, said Amuno.
Cadmium levels were also high in both sets of hares, said Niyogi.
鈥淲e also found quite a bit of cadmium in the animals that were collected 20 kilometres away from the mine site,鈥� he said. 鈥淣ot as high as compared to the animals that were collected close to the mine, but nonetheless there was still some cadmium.鈥�
Hares鈥� relatively low mobility during their lifespan and their tendency to ingest soil during times of physiological stress make them an important indicator species for understanding environmental conditions, said Amuno.
That鈥檚 part of the reason the researchers chose the small mammal for their study.
Hares are also trapped and used for pelts, Amuno said.
However, the findings are only a baseline study meant to help paint a picture of the health condition of snowshoe hares in the Yellowknife area, Amuno said.
The pair was unable to comment on what their findings mean for human health.
鈥淲hat we have here is just the data,鈥� said Amuno. 鈥淲e鈥檝e already shared it with the GNWT and it鈥檚 up to them to make that decision if the levels reported in our study (are) a safe level or not (for consumption).鈥�
Dr. Andre Corriveau, the NWT鈥檚 chief public health officer, said the study isn鈥檛 concern enough to issue a public health advisory.
The sample size was fairly small, he said, adding it would be difficult to assess the health effects of consuming snowshoe hares from around the mine because the study didn鈥檛 examine the animals鈥� meat.
鈥淚t鈥檚 best to avoid harvesting any traditional or local foods around contaminated sites, whether it鈥檚 Giant Mine or around Con Mine or around other mines in the territory,鈥� Corriveau advised. 鈥淯sually if there鈥檚 one contaminant, there鈥檚 more.鈥�
He said he expects an ongoing study by University of Ottawa researcher Dr. Laurie Chan, which is exploring human health effects of the Giant Mine remediation project, to provide the most telling results.
Yellowknifer requested an interview with the Department of Environment and Natural Resources to ask about whether the GNWT is using the study鈥檚 findings on snowshoe hares and what other work is being undertaken on arsenic and the environment.
鈥淭he results of the study on snowshoe hares were shared with the (Giant Mine Remediation Project) team but have not been incorporated into the (Human Health and Ecological Risk Assessment) since the study was designed to detect arsenic concentrations in bones and teeth rather than the muscle/meat that humans typically consume,鈥� said Meagan Wohlberg, spokesperson for the department, in an email.
鈥淭he (assessment) did have an ecological component, and determined that there may still be ecological impacts to small mammals using the site. These impacts are expected to lessen following remediation.鈥�
The GNWT reviews new studies, which may result in new or updated public health advisories, she added.
In May, Environment and Natural Resources Minister Robert C. McLeod announced the department was collaborating with the federal government and universities on studies about contaminants in fish, soil, water and sediment in the Yellowknife region.
