Microplastics can now be detected in the most remote regions, such as in Arctic sea ice or deep-sea sediments. The tiny particles get there with the help of ocean currents. But this may not be the only way: tyre tread abrasion, paint particles, synthetic clothing fibres and other materials could also be transported through the atmosphere by wind. There, snow catches some of the particles and brings them down to the earth. At least, this is what is known to occur with other types of air pollution.
Recently researchers have, for the first time, detected microplastics in snow samples. The study, under the direction of the German Alfred Wegener Institute, also included
scientists from SLF. In winter 2017/18, they collected new snow in the Flüela Valley near Davos. The samples and others from Bavaria and the North Sea island of Helgoland were compared with Arctic snow from Svalbard and various ice floes north-east of Greenland.
The samples with the largest quantities of microplastics were those from Bavaria, which were collected directly next to a country road: up to 150,000 particles per litre of melted snow. But even the Arctic samples contained up to 14,000 particles – an astonishing amount for such remote regions. The concentrations in the
alpine Flüela Valley were similarly high.
The results indicate that microplastics probably reach the Arctic with the global wind systems. Further studies are, however, needed to find out how the particles enter the atmosphere in the first place.
(Claudia Hoffmann, Diagonal 2/19)