Are Microplastics in the Atmosphere a Health Risk?

Ute Eppinger

August 23, 2019

Microplastic particles have already been detected in seawater, mussels, seafood and fish, as well as in drinking water. Now researchers have found high concentrations of microplastics even in the snow of the Arctic and the Alps.

A study by Dr Melanie Bergmann and Dr Gunnar Gerdts from the Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research in Germany shows that the atmosphere absorbs these tiny particles, transports them over long distances and then washes them out of the air again through snow.

The study results were published on the 14th August in Science Advances . Dr Bergmann and Dr Gerdts’ team has provided the first international data on microplastics in snow, and also demonstrated that significant concentrations of artificial materials are detectable in remote arctic and alpine locations.

So far, there has been little research into whether, and what quantity, of microplastic particles are transported through the atmosphere. Only a few studies have been carried out on this.

A study published in Nature Geosciences in April this year showed that in a remote mountainous region in the Pyrenees, it rained more than 350 microplastic particles per day per square metre – even though there are no large cities or industrial facilities nearby.

In 2015, French scientists were able to prove that rain and sewage in Paris contained microplastic particles.

"It is obvious that a large quantity of microplastics gets into snow through the air. Some of it probably comes from Europe," says study author Dr Bergmann in an AWI news release.

The theory is supported by older studies on pollen grains. These, too, can reach the Arctic through the air. Pollen is similar in size to microplastic particles. Saharan dust is also capable of covering distances of 3500 km or more, as far as the Northeast Atlantic.

Given the meteorological conditions, there is no doubt amongst AWI experts that a majority of these particles in Europe, and especially in the Arctic, are found in air and snow. "This additional transport route also explains the high levels of microplastics we have found in previous studies in Arctic sea ice and the deep sea," says Dr Bergmann.

What Is the Inhalation Risk?

Just how dangerous is microplastic for us humans? Hardly any studies have been carried out on this, Dr Gerdts confirms to Medscape's German Edition . "We have always felt that it is necessary to look at the atmosphere, because it could play an important role, but research depends on a lot of things, including funding."

"When we discover that large quantities of microplastics are transported by air, the question naturally arises as to the extent to which we inhale plastic and we are polluted in this way. Older results from medical research provide the first clues," says Dr Bergmann.

"Microplastics not only reach humans via the seas, but also through the air. Microplastics are definitely there. The question is, in what concentration are they present in the air," emphasises Prof Frank Kelly, director of the Environmental Research Group at King's College London, which researches microplastics in London air, speaking to CNN.

Prof Kelly and colleagues examined 50 pupils at Lordship Lane Primary School in Haringey, north London, and concluded that children's lung development was being inhibited by the release of microplastics from car tyres. "We know that some of the components from brake wear, together with micro-plastics from tyres, will be irritating and causing reactions in the lung, which over time would not be good for our health," Prof Kelly explained to Channel 4's Dispatches.

There are no available estimates of inhalation risk: "There has been virtually no research on the risk of inhalation of airborne microplastic particles," confirms Dr Gerdts.

One of the few works is a Danish study published in Scientific Reports in June. Whether, and to what extent, indoor atmospheres are contaminated with microplastic particles, was investigated using a breathing thermal manikin (an anatomical model of the human body). Samples were taken from three flats and analysed using Fourier Transformation Infrared Spectroscopy (FTIR Spectroscopy). All samples were contaminated with microplastics, with concentrations between 1.7 and 16.2 particles per cubic metre.

The study suggested that microplastic particles represent a non-negligible proportion of indoor air particles that can be inhaled and have negative health effects.

Polyester was the predominant synthetic polymer in all samples (81%), followed by polyethylene (5%) and nylon (3%).

Particles of Varnish, Rubber, Polyethylene and Polyamide

In the new study, Dr Bergmann and colleagues analysed snow samples from ice floes from the Fram Strait (the sea route between the Greenland Sea in the North Atlantic and the Wandel sea in the Arctic Ocean). For comparison, they used snow samples from remote locations in the Swiss Alps and populated European locations, such as Bremen and Bavaria.

FTIR spectroscopy was used to identify microplastics in 20 out of 21 samples. Although the microplastic concentration of Arctic snow was significantly lower (14,400 particles per litre) than near a road in the Bavarian Alps (154,000 particles per litre), it was still significant.

The snow contained high concentrations of microplastics at all sites – even in remote areas of the Arctic, on the Svalbard archipelago and in the snow of drifting ice floes.

The polymer composition of the particles found varied greatly, but varnish, rubber, polyethylene and polyamide dominated overall.

In the Arctic, nitrile rubber, acrylates and paints were found, suggesting the origin was ships and oil platforms. Nitrile rubber is often used in seals and hoses, plastic-containing paints for surface coating of buildings, ships, cars and offshore oil platforms.

In the area around a major road in Bavaria, on the other hand, the samples mainly contained various types of rubber, which can be found in car tyres.

According to the researchers, detection of unexpectedly high amounts of these smallest plastic particles in the fresh snow of the most isolated areas of the world underlines the extent of potentially toxic contamination in the earth's atmosphere.

Concentrations Higher Than in Studies by Other Researchers

The microplastic concentrations found by Dr Gerdts, Dr Bergmann and colleagues are several times higher than those in studies by other researchers who have investigated dust deposits, for example.

Dr Gerdts explains why this might be the case: "Firstly, snow is extremely efficient when it comes to washing microplastics from the atmosphere. Secondly, it could be due to the infrared spectroscopy we used, which allowed us to detect even the smallest particles – up to a size of only 11 microns."

Dr Gerdts and colleagues melted the snow, poured the melted water through a filter and examined the residue trapped in the filter using an infrared microscope. Depending on the type of plastic, different wavelengths of infrared light are absorbed and reflected, so that these can be attributed to a specific plastic.

In contrast to other studies in which microplastics were sorted out by hand under the microscope, the AWI researchers chose a more advanced method: "We have automated and standardised the technology to eliminate errors that sometimes creep in with manual analysis.

"It is important and desirable that the topic of microparticles is now pursued by as many disciplines as possible and that the results are mutually beneficial," concludes Dr Gerdts.

On the 22nd August 2019, the World Health Organisation issued an assessment on the risk of microplastics in drinking water. It concluded there is no evidence so far that they pose a risk to humans.

Bergmann M, et al: Science Advances (online) published 14th August 2019.

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