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The Big (Tiny) Problem

Microplastics in our waters may threaten ecosystems and accelerate the melting of Arctic sea ice. But are we ignoring the greater danger at the heart of this climate conundrum?

By Sean Moore

Feiyue Wang was standing 20 metres from the river of lava, his thoughts bouncing between safety and scientific checklists and oh-my-is-this-cool.

“For a guy who works in extreme environments, this was a treat,” says Wang, a Canada Research Chair in Arctic Environmental Chemistry. “It was dangerous, but no matter where you’re doing field work, the basic rule is the same: Don’t do stupid things.”

He generally researches mercury in the Arctic, but last summer found himself at the foot of an erupting volcano in Iceland to study its secrets, as well as in a lab investigating microplastics. Why? Because Wang sees this trio of characters—mercury, volcanoes and microplastics—as being weaved together in an evolving story of climate change and adaptation few have yet to hear about. Humans are also a central character, doing eventful things such as, say…laundry.

A typical North American washing machine strips and expels 533 million microfibres of plastic from clothes every year, and even though municipal filters do a great job, across the continent 3.5 quadrillion plastic fibres (the weight of 10 blue whales) still slip past and find freedom to roam the world through waterways, according to the Ocean Wise Conservation Association. And much of all this plastic travels to the Arctic Ocean because, although this body of water only accounts for about one per cent of the global ocean volume, it receives more than 10 per cent of river discharge.

Laundry is just one of the many sources of marine microplastics: Every year about 20 million metric tonnes of plastic waste is mishandled and finds its way into the planet’s water systems, a 2022 paper in Nature notes.

Today, one can find plastic in the Arctic’s snow, ice, and on its ocean floor. It’s everywhere and it alarms many, but not Wang. He holds a more stoic view, for now.

“The bottom line is: If microplastics keep increasing in our environment it has the potential to affect ecosystems and, in the Arctic, sea-ice strength and the albedo effect [how a surface reflects light, which contributes to melting] but not at this stage. We’re far away from that. And let’s remain hopeful we’ll never be reaching that stage,” says Wang.

Yet microplastics, generally defined as any bits smaller than a pencil eraser, are concerning for another, lesser-known reason—one that few people seem to be talking about, explains Wang and PhD candidate Kedong Zhang, who works alongside him at the Sea-ice Environmental Research Facility, or SERF, a globally unique lab that allows researchers to run controlled experiments in ice.

“People should worry about microplastics, sure, but I think most people are worried about them from the wrong angle,” says Zhang. “Microplastics are not as bad as people think, or not as bad in the way people think they are. Microplastics carry other contaminants and that should be much more concerning to people. Contaminants such as mercury, a neurotoxin, can attach to microplastics and move around in new ways. That is what should concern people.”

Contaminants such as mercury, a neurotoxin, can attach to microplastics and move around in new ways. That is what should concern people.

Incidentally, 50 years ago, these two problems—microplastics and mercury—were identified separately around the same time in the Arctic.

In 1972 it came to light that Inuit from coastal communities such as Tuktoyaktuk and Ulukhaktok had the highest blood mercury concentrations in Canada. It confounded scientists at the time because they were far from any industrial source. The Arctic should have been one of the last places on Earth to find such high levels.

Meanwhile, during an unrelated study, scientists surveyed a 10-kilometre stretch of beach on an uninhabited Alaskan island looking for plastic and they tallied about 5,300 fragments, mostly from Japanese and Russian fishing nets. That was the first count of plastic in the Arctic.

In recent times much more attention has been given to microplastics than mercury. A quick search of mass media finds 51,015 stories involving “microplastics” in 2021, while 2,773 mention “methylmercury,” the type of mercury of deepest concern for human health. How many spoke of both? Just 70, and usually not linking them together in the same sentence, and that, recent UM studies suggest, must change.

Zhang has been testing various microplastic beads in SERF’s simulated Arctic environment to understand the chemistry of their weathering process. “There is a hint plastic weathers faster in the Arctic than in other environments,” Zhang says. “You’d think it was like a fridge, where the cold preserves it, but actually the UV and ocean chemistry in the Arctic seems to weather the plastic faster than in the Mediterranean, for example.”

New plastic doesn’t bind with mercury—it’s the porous surfaces of weathered plastic that act as a carrier for contaminants, possibly attracting more mercury through chemical and physical processes.

The resulting danger is that as creatures ingest more weathered plastic, the plastic may get excreted, but the mercury stays behind. “Mercury is one of the most concerning pollutants in the world because it can bioaccumulate and biomagnify,” Zhang says. “This should concern governments to a great deal.”

Since contaminants like mercury and plastic travel the world, it requires international cooperation to mitigate. Humanity came together and signed the Minimata Convention in 2017, which presents a legally binding international roadmap to reduce mercury emissions from industrial processes. But, Wang notes, that does not immediately solve the problem for two reasons: one, mercury pollution can linger for many decades (so whatever problem we have now, we have for the foreseeable future); and two, Earth creates it, too.

Volcanoes spew a lot of mercury. How much? That has yet to be discovered—estimates vary from 1 to 1,000 metric tonnes per year—because it is rare for a scientist such as Wang to be at an eruption when it occurs. And many volcanoes can also emit mercury gas for years without ever erupting; we just haven’t gotten around to measuring all of these events yet.

But Fagradalsfjall’s eruption in Iceland in March 2021 was on Wang’s radar, having sent his third-year PhD student Brock Edwards there to measure mercury emissions shortly after it began. And just before Wang’s planned follow-up trip in 2022, the volcano unexpectedly erupted a second time. Within a matter of days, they were standing next to that river of lava. The data Wang and Edwards are now sifting through is of tremendous value.

While we know a good deal about how humans put mercury into the environment, we know very little about the natural inventory.

What we do know is most mercury is emitted from the volcano as a gas and it can circle the globe for about a year, all the while oxidizing, before it settles down. To gloss over the chemistry, the now oxidized mercury is eager to react and so when it lands on soil or water, much of it comes into contact with specific and ubiquitous bacteria that further convert it into methylmercury, an extremely toxic substance. (To make matters worse, warmer waters resulting from climate change make these bacteria more active.)

“In this way, no part of the world is safe from airborne mercury,” Edwards notes.

No part of the world is safe from airborne mercury.

Methylmercury is the form of mercury that accumulates and magnifies in the tissue of fish and marine mammals. Indigenous Peoples who rely on these food sources are thus more susceptible to its health risks. Because mercury is transported globally, a fish from a seemingly pristine northern lake (or a seal from the Arctic Ocean) can contain as much mercury, if not more, than those caught in the more urbanized south.

“Thanks to the Minimata Convention, we will see a decline in mercury levels from anthropogenic sources,” Wang says, “but if natural and legacy mercury are still relevant, then recovery is going to take longer. And for communities reliant on traditional diets in the North, we can’t just say, ‘Don’t eat fish or seals.’ So, we work with Indigenous communities in identifying what animals contain what concentrations of mercury and in co-developing adaptation and mitigation solutions. And this is a problem everyone needs to be aware of because, even in Canada, we can have lakes that are very contaminated with mercury—more so even than countries with less regulation. It is a global problem.”

Today, many Indigenous people living in the Arctic have blood-mercury concentrations beyond the safe threshold.

How microplastics can exacerbate this problem is something the SERF lab will help answer. And soon UM will officially open the Churchill Marine Observatory—another globally unique lab, this time in the Arctic—at which Wang is the project lead. It will help us better understand this plastic-mercury soap opera we are only now tuning into.

What becomes of global health if methylmercury is hitching a ride on ever-increasing fleets of microplastics into a fish, a cow or us, over and over again?

“Research has to be driven by curiosity,” Wang once mused, on the eve of SERF opening a decade ago. “But in the environmental field, it is driven by real-world problems as well. And it can be depressing stuff, but there is always hope.”

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