By Matt Simon
Welcome to the year of the plastic menace, a nonstop flow of terrible news about how the ocean and its organisms are choking on macroplastic, while microplastic particlesâ€”bits less than 5 millimeters longâ€”are wafting their way to supposedly pristine mountaintops in Europe. It seems nowhere is safe from microplastic pollution, not even Monterey Bay in California, which otherwise is one of the greatest conservation success stories in history.
Now there’s yet another reckoning over humanityâ€™s hopeless addiction to plastic. Researchers and citizen scientists collected snow from two dozen locations, ranging from remote Arctic ice floes (floating chunks of ice, essentially) and the Norwegian archipelago Svalbard to northern Germany and the Bavarian Alps. The results are devastating: In its highest concentrations in Bavarian snow, microplastic particles numbered 150,000 per liter. In Arctic snow, the highest sampling was less at 14,000 per liter, but perhaps even more horrifying in its context, given the northern remoteness of the location.
Matt Simon covers cannabis, robots, and climate science for WIRED.
The big question is, where are these microplastic particles coming from? The researchers couldnâ€™t nail down an exact location, but they reckon the particles are blowing in from the cities of Europe. â€œSnow â€˜scavengesâ€™ the particles in the air and brings them down,â€� says marine ecologist Melanie Bergmann of the Alfred Wegener Institute for Polar and Marine Research, lead author of a new paper in Science Advances. Thereâ€™s precedent here too: Previous work has shown that pollen, which is about the same size as these microplastic particles, also travels great distances north into the Arctic.
The types of plastics Bergmann and her colleagues found may lend some clues as to their originsâ€”a lot of rubber and polymer varnish in particular. â€œThat kind of surprised us, because how do varnish particles make it into the air and so far north?â€� Bergmann asks. Ships are coated with varnish to ward off fouling organisms, but if was coming from them, youâ€™d expect the particles to show up in water, not in snow samples. â€œBut then on land you have all the cars basically painted with varnish, which often contains polymer. Many buildings nowadays are also painted with varnish. Offshore platforms have these, so it’s actually quite a widespread thing.â€�
Also, nearly all of the plastic that researchers think enters the environment goes missing. â€œAt the moment, that’s a big question in this field of research,â€� says Bergmann. â€œWhere’s all the plastic? Because it’s estimated 8 million tons of plastic is being carried into the ocean every year, and we’ve only found about 1 percent of it.â€�
A bit of caution with this research: The scientists found quite a bit of variability in the concentrations of microplastic particles they found in the snow samples. So that sample from Bavaria that tallied 150,000 particles, they took near a roadâ€”the other two Bavarian samples were closer to 5,000 particles. And the ice floe sample of 14,000 particles stands in contrast to the other ice floe samples, which tallied very few or even zero particles. This raises the specter of contamination by their sampling equipmentâ€”though the researchers argue that none of this equipment contained varnish, the main polymer they found in the snow samples.
The complicating factor here may not be methodological, but temporal. The researchers canâ€™t know when these particles landed in the snow, so some areas may be cursed with certain wind events that deposit a plethora of microplastic. â€œWe have a lot of uncertainties with atmospheric plastics because we don’t know how it behaves in the atmosphere,â€� says Steve Allen, an environmental pollution scientist at the University of Strathclyde, who wasnâ€™t involved in this new work. â€œIt could be flux coming from a particular weather pattern and it wasn’t noted. So it’s entirely possible that they’re quite correct, that those numbers are right.â€�