Microplastic is everywhere: in the deep sea, between the grains of sand of the local rivers, in the perpetual ice and isolated reports also in our bodies, even in beer brewed according to the German purity law. Now researchers have been able to detect the microfine particles even in the snow - in the Bavarian Alps and on deserted ice floes in the Arctic. Does that change anything? Yes. Because the finds in the snow are a clear indication of a new, bigger problem: Microplastic spreads in the air all over the world. The air we need to breathe.

For the study, the research team of the German Alfred Wegener Institute compared snow samples from densely populated areas around Bremen and in the Bavarian Alps with completely abandoned places such as Spitsbergen or Arctic ice floes. Their result, which they published in the journal Science Advances (Bergmann et al., 2019), contained tiny microplastic particles in all samples. In the Arctic as well as in populated areas, the microplastics mostly consisted of tiny remnants of paints, rubber, PET bottles or synthetic textiles - all materials that we use in everyday life.

In densely populated areas, the concentrations were significantly higher than in the Arctic - most contained a sample from the edge of a highway in Bavaria with more than 150,000 particles per liter of molten snow. But also freshly fallen snow in the far north contained microplastic in remarkably high concentrations, considering how rarely an Arctic ice floe comes into contact with humans and thus also with plastic. For example: on a plaice on the Fram Strait, the sea route between Spitsbergen and Greenland, the researchers found more than 14,000 particles per liter of snow.

Microplastic hovers over thousands of miles to the Arctic

Snow has a special property, which the scientists used in their investigation: While the frozen ice crystals slowly fall from the clouds to the earth's surface, they filter small particles of airborne particles - including the tiny microplastics. If you find the particles in freshly fallen snow, it is very likely that they previously floated in the air. In contrast, particles in the ice of the Arctic can also come from the seawater.

"The study shows that the air from which microplastics has been deposited with the snow is an important transport route for microplastics," says the deep-sea ecologist Melanie Bergmann, the lead author of the study. This way it could reach even the most remote regions of our earth. According to Bergmann, the particles are very likely transported by the wind over long distances. The majority of the particles that reach the Arctic probably originate from the European area. A look at the transport of other suspended particles to the north makes this plausible: Large pollen grains fly in a few days from Central Europe to Spitsbergen, and Saharan dust is blown for at least 3,500 kilometers, ie to the Northeast Atlantic ( Science Advances: van der Does et al. , 2018).

Really surprising, therefore, the new find does not come. Researchers have long suspected that microplastic floats in our atmosphere, which then either slides to the ground or is captured by rain and snow and transported to the ground ( Environmental Science and Pollution Research: Cai et al., 2017). For example, when measurements were taken in French rivers, scientists found fivefold higher microplastic concentrations after it had rained ( Environmental Chemistry: Dris et al., 2014).

It is hardly known what microplastic causes

The new study says nothing about the consequences of microplastic contamination. Exactly how plastic residues affect ecosystems is the subject of many current - and not yet completed - research projects. However, as the study shows, people probably take in more microplastic into their bodies every day than previously thought, through breathing and precipitation, which flushes floating microplastic into our water cycle.

Nobody can say for sure what exactly that means for our health. Scientists suspect that pollutants can accumulate on plastic particles, be carried into the body via food or the air and cause inflammation there ( Environmental Science & Technology: Wright et al., 2017), or that inhaled plastic damages or even damages the lung tissue Cancer ( Environmental Pollution: Prata, 2018) - however, there is no conclusive evidence for any of these hypotheses; so far, these are purely guesses.

Nevertheless, the study authors urge to take the results seriously. For example, they warn against randomly sweeping freshly fallen snow off roads into nature. A large pile of snow can contaminate the soil, according to the study.

You can read more about plastic and garbage in our focus on "Life in Disposable Mode". ZEIT ONLINE follows the routes of the garbage and shows what he does with humans and animals and how he could better avoid them.