A polar bear walks along the ice flow in the Franklin Strait, Nunavut, on Jul. 23, 2007.Jonathan Hayward/The Canadian Press
A landmark report reveals that atmospheric mercury in the Arctic Circle has swelled tenfold since the Industrial Revolution in the mid-1800s, posing increasing health risks for wildlife and Indigenous communities in the region.
The report, published Tuesday, was produced by the Arctic Monitoring and Assessment Programme (AMAP) arm of the Arctic Council, an alliance of eight countries with territories at the top of the world, including Canada and the United States. It reviewed 20 years of data from scores of smaller studies to produce the most comprehensive understanding yet of how mercury appears in the water, atmosphere and soil of the Arctic. (A 2011 AMAP mercury report was much smaller in scale.)
Signs of mercury absorption in tree rings showed the chemical first became significantly present in the Arctic during the Industrial Revolution and then continued to amass. Today, 90 per cent of mercury pollution comes from industrial emissions and other human sources. About 98 per cent of these emissions are produced far from the Arctic Circle but carried north by the atmosphere, rivers and oceans, creating higher concentrations of the element than in southern regions.
Aquatic life-forms such as plankton absorb mercury suspended in ocean water and transmit it to animals that eat them. This results in high concentrations of mercury in animals higher up the food chain, including polar bears and seals. Ultimately, toxic compounds can be passed on to Indigenous communities that hunt for subsistence or cultural tradition – endangering people who are already among the most exposed to mercury in the world.
Toxic mercury affects animal and human health in the Arctic
Mercury from emissions in southern latitudes is ferried to the Arctic Circle by rivers, oceans and the atmosphere. There, it moves around in a complex series of processes involving animals and humans. Experts say the climate crisis is affecting these processes in direct ways, such as mercury leaching into oceans from melting permafrost, and indirect ones, such as animals changing their diets and locations in search of increasingly scarce food and habitat
Source of mercury
RINGED SEALS
Micro-organisms absorb mercury in the water and pass it up the food chain to ringed seals
Mercury has been observed in seals for 45 years, though levels have been mostly steady
Warming temperatures are melting ice that seals need, driving them to new areas
PEOPLE
Inuit peoples in the Arctic Circle eat seals as part of a traditional diet that is more affordable than food shipped north
A 2007 study showed seal liver accounted for 59% of mercury exposure for adults and 15% for children
Mercury can impair brain development for fetuses in utero
POLAR BEARS
Ringed seals are a major part of polar bear diets
When seals grow scarce, bears burn mercury-laced fat to survive, introducing mercury into their bloostream
Mercury impairs the immune system and fertility
TAHMEED SHAFIQ AND MURAT YUKSELIR / THE GLOBE AND MAIL
Toxic mercury affects animal and human health in the Arctic
Mercury from emissions in southern latitudes is ferried to the Arctic Circle by rivers, oceans and the atmosphere. There, it moves around in a complex series of processes involving animals and humans. Experts say the climate crisis is affecting these processes in direct ways, such as mercury leaching into oceans from melting permafrost, and indirect ones, such as animals changing their diets and locations in search of increasingly scarce food and habitat
Source of mercury
RINGED SEALS
Micro-organisms absorb mercury in the water and pass it up the food chain to ringed seals
Mercury has been observed in seals for 45 years, though levels have been mostly steady
Warming temperatures are melting ice that seals need, driving them to new areas
PEOPLE
Inuit peoples in the Arctic Circle eat seals as part of a traditional diet that is more affordable than food shipped north
A 2007 study showed seal liver accounted for 59% of mercury exposure for adults and 15% for children
Mercury can impair brain development for fetuses in utero
POLAR BEARS
Ringed seals are a major part of polar bear diets
When seals grow scarce, bears burn mercury-laced fat to survive, introducing mercury into their bloostream
Mercury impairs the immune system and fertility
TAHMEED SHAFIQ AND MURAT YUKSELIR / THE GLOBE AND MAIL
Toxic mercury affects animal and human health in the Arctic
Mercury from emissions in southern latitudes is ferried to the Arctic Circle by rivers, oceans and the atmosphere. There, it moves around in a complex series of processes involving animals and humans. Experts say the climate crisis is affecting these processes in direct ways, such as mercury leaching into oceans from melting permafrost, and indirect ones, such as animals changing their diets and locations in search of increasingly scarce food and habitat
Source of mercury
RINGED SEALS
Micro-organisms absorb mercury in the water and pass it up the food chain to ringed seals
Mercury has been observed in seals for 45 years, though levels have been mostly steady
Warming temperatures are melting ice that seals need, driving them to new areas
PEOPLE
POLAR BEARS
Inuit peoples in the Arctic Circle eat seals as part of a traditional diet that is more affordable than food shipped north
Ringed seals are a major part of polar bear diets
When seals grow scarce, bears burn mercury-laced fat to survive, introducing mercury into their bloostream
A 2007 study showed seal liver accounted for 59% of mercury exposure for adults and 15% for children
Mercury impairs the immune system and fertility
Mercury can impair brain development for fetuses in utero
TAHMEED SHAFIQ AND MURAT YUKSELIR / THE GLOBE AND MAIL
Researchers say the climate crisis is worsening the situation as mercury compounds leach into the environment from melting ice and permafrost. Climate effects also warm and acidify ocean waters, which can drive marine animals northward where atmospheric mercury concentrations are greater.
The report urges policy-makers to consider “stringent but feasible” limits on emissions that would “reduce future Arctic mercury concentrations over both the near term and the medium term,” and to conduct future monitoring in the region in collaboration with the Indigenous communities who are most affected.
Robert Letcher, a senior research scientist at Environment Canada who coled the report’s section on consequences for wildlife, describes mercury in the Arctic as “pervasive.”
It is difficult to say how endangered Arctic animals are as whole, because each species is exposed to and affected by mercury differently. By analyzing species individually, researchers found that many animals were at low- or moderate-risk levels, but Dr. Letcher cautioned against taking these estimates as gospel because the long-term health consequences of mercury are understudied and continuously changing under the stresses of climate change.
Some localized populations of animals are more at risk than others, such as the polar bears in Canada around Hudson Bay. Ice forming later in the year has a “statistically significant influence on slightly increasing the mercury in polar bears” in that region, Dr. Letcher said. As seals become scarcer or more difficult to hunt, the bears burn their mercury-laced fat stores to survive and the contaminant enters their blood, where it can affect fertility and weaken their immune systems.
Conversely, University of Manitoba professor Lisa Loseto noted that the beluga whales in the Mackenzie River estuary her team studied had less mercury in their systems than previously observed – although that also might be the result of climate change forcing the fish beluga typically eat to migrate. These shifting beluga diets “complicate their exposure story,” she said.
In recent years, Dr. Loseto’s team has been visiting whaling camps to learn whether hunters have noticed anything different about beluga populations. Working in the Inuvialuit Settlement Region of northern Yukon and the Northwest Territories, Dr. Loseto relies on such collaborations with Inuit communities. The partnerships angle data collection toward the concerns people have about contaminants in their environment, and Indigenous knowledge can even change the way research is conducted. For example, hunters shared that oil rendered from the whales’ fat had changed in colour and consistency, which signalled to Dr. Loseto that beluga diets were changing.
Incorporating traditional knowledge into their scientific studies has long been a concern for researchers who work on issues affecting Indigenous communities. The AMAP report is clear this should be a priority for future mercury research in the Arctic, as part of a broader effort to remove patriarchal biases in the sciences and allow Indigenous communities to govern themselves.
Lucy Grey, report co-author and federal affairs liaison officer with the Makivik Corporation, a representative body for Inuit people in the northern Quebec region of Nunavik, said self-determination is particularly important in mercury health research.
The 2018 Global Mercury Assessment study from the United Nations identified Indigenous communities in the Arctic as among the most exposed to mercury in the world. The element is absorbed predominantly from locally hunted foods such as seal and Arctic char. Pregnant women are the most vulnerable, as mercury can impair brain development of a fetus in utero.
But these same foods, often called “country food,” are vital staples for Inuit communities, not just as part of a traditional diet but as an alternative to the expensive groceries shipped from the south that many families cannot afford. Many country foods also have important health benefits, Ms. Grey said, such as beluga tail skin, which contains high levels of selenoneine, a selenium-compound believed to reduce the effects of mercury absorption, and is eaten more by women than men.
She said food advisories should be data-driven but ultimately left to Inuit communities to announce, as opposed to being administered by Canadian governmental bodies.
“This is food sovereignty,” Ms. Grey said. “We’ll consider all the risks … and then we make the decision. It’s a collaborative effort within the region, led by Inuit.”
What is needed are policies that prevent mercury from entering the Arctic in the first place, she said, as the overwhelming majority of emissions are produced outside the region, but “found in our dinner plates.”
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