When Melanie Bergmann, an ecologist at the Alfred Wegener Institute in Germany, collected snow and ice samples for her new study, she had to work extra hard not to contaminate them. She and her colleagues always looked for the freshest snow. They always stood with their backs to the wind. They picked up the ice with unorthodox metal tools—including, at one point, a household soup ladle—and deposited it in glassware.
And—most unusually—they always worked with their bare hands, never touching the plastic gloves that most scientists automatically don in the field. “Plastic gloves,” Bergmann told me, “are not the best if you want to sample microplastics.”
In just the past decade, scientists have discovered that microplastics—defined as any plastic detritus that’s about the size of a sesame seed or smaller—are a major new pollutant, the spread of which we’re only now understanding. Microplastics are present in 94 percent of tap water in the United States, according to one study. They form as larger plastic items—toys, clothing, paint chips, car tires—get worn down and torn to shreds.
In a new study, published today in Science Advances, Bergmann and her colleagues looked at whether microplastics collect in the air, as well. They looked for microplastics trapped in snow from the Alps, sea ice from the Arctic Ocean, and snow from the High Arctic island of Svalbard. Snow tends to be good at shaking out particles hanging in the air, so any microplastics in the snow would likely have come from the air, especially in the remote Arctic locations.
Not only did they find microplastics; the “sheer number” the team uncovered shocked Bergmann. “We did expect to find microplastics, but the numbers that we found were a big surprise,” she said. Thousands of particles of microplastic were in nearly every sample from the Arctic; a single liter of snow contained 14,000 grains of the stuff. Microplastics were even more abundant in Europe, where there were as many as 150,000 grains of microplastic per liter of snow.
To translate: If you melted down enough Arctic ice to fill a one-gallon milk jug, it might contain as many as 53,000 shreds of microplastic.
Those microplastics may have fallen as snow, but they arrived in the Arctic through the atmosphere. The study shows that microplastics, shorn from human products and carried by global trade winds, are now accumulating in some of the harshest, most remote places on Earth.
The study also offers some of the strongest evidence so far that microplastics—for which human health risks are still very poorly understood—might be virtually ubiquitous in the air, water, and human environment. Tiny shreds of plastic might enter your lungs when you sniff a spring breeze, the study suggests, and they might slosh around your stomach when you drink a glass of water. Yet we still have little grasp on what, if anything, microplastics do once inside the human body.
In the animal world, microplastics seem to already be causing harm. They can block the digestive tracts of fish and insects. Some chemicals present in plastic might affect animal endocrine systems. In April, a dead sperm whale with 48 pounds of plastic in its system washed ashore in Sardinia.
Microplastics may pose a particular threat to Arctic life because the Arctic serves as a meeting point for ocean currents and trade winds from across the Northern Hemisphere. A recent study found that the Arctic Ocean contains more plastic waste than any other ocean, with roughly 300 billion pieces of detritus. When Bergmann and her colleagues combed the deep-sea floor, they found roughly 6,000 pieces of microplastic per kilogram of dry sediment. “That’s a lot,” she said.
The new study makes for “interesting and terrifying stuff,” said Joe McConnell, a professor at the Desert Research Institute, in an email. He studies how Arctic snow collects other forms of air pollution, and he was not connected to the microplastic research. “The Arctic has been contaminated by mid-latitude industrial emissions for most of the past three millennia—starting as early as the Romans and likely even earlier—so I don’t find it too surprising that very small [microplastic] particles are transported to and deposited in remote regions such as the Arctic or the Alps,” he said.
What was worrying, he said, was that Bergmann and her colleagues found the most particles at the smallest range they looked for. (The new paper could not detect microplastics smaller than 11 micrometers across, which is about the same width as cling wrap.) Since pollution particles are generally more harmful at smaller sizes, it suggests that the study doesn’t capture the most dangerous risks. “The very, very small particles—which likely have the most serious health risks—may be even more ubiquitous in the remote environment, which is especially troubling,” McConnell said.
Bergmann, meanwhile, found herself most surprised by the origin of the microplastics. When she and her colleagues analyzed their samples, they imagined they might find a lot of polyethylene, the most common plastic in the world, which makes up kids’ toys and single-use plastic bags. And they did. But far and away the most common type of plastic was from varnish. It occurred in every sample, in many different sizes, “even in the Arctic,” she said.
It seemed weird. “I’ve seen [varnish microplastic] in deep-sea sediment, but there you can assume it’s from ship paint,” she told me. But how does varnish get into the air? “I started thinking, and it occurred to me how many of our surfaces are actually coated in polymer-based varnish these days,” she said. “Many buildings, offshore construction, cars, ships. [Then] it’s exposed to sunlight, wind, wear and tear, and smaller fragments become loose and get transported with the air.”
And the second-most-common type of microplastic in their samples was rubber, like the kind used to make car tires. Bergmann, with admirable understatement, called these results “kind of problematic.”
“With our current political and economic system, we find it difficult to reduce single-use plastic, but that’s actually the easy part,” she said. “Reducing varnish or the use of car tires … that’s a lot more difficult.”