Record concentration of microplastic discovered in Arctic sea ice, study says

A study published in the journal Nature Communications on Tuesday, April 24, found higher amounts of microplastic in Arctic sea ice than ever before.

Researchers at the Alfred Wegener Institute (AWI) in Germany, Helmholtz Centre for Polar and Marine Research, studied ice samples from five regions along the Transpolar Drift and the Fram Strait throughout the Arctic Ocean.

They found that this region contained up to 12,000 microplastic particles per liter of sea ice. However, most particles were smaller than a twentieth of a millimeter (mm) or 11 micrometers.

"The different types of plastic showed a unique footprint in the ice, allowing us to trace them back to possible sources. Thus, high proportions of polyethylene indicate long-term transport routes from the Atlantic and Pacific oceans," AWI Biologist and Study First Author Dr. Ilka Peeken said.

“The high percentage of paint and nylon particles pointed to the intensified shipping and fishing activities in some parts of the Arctic Ocean,” Peeken said in an email.

It was already known from a previous study that microplastic is concentrated in sea ice. Peeken and her team hoped to reveal if sea ice is really a "sink" for microplastic and if it also can serve as a transport vehicle for microplastic.

"During sea ice growth, characteristic salt fingers are developed, which will likely enrich the particles. In addition, sea ice algae also embedded in the ice excrete exopolymer particles, which also can serve as a glue for the microplastic. Thus, during sea ice growth the microplastic are embedded in the ice," Peeken said.

The sea ice binds this plastic litter for two to eleven years, which is the time it takes for ice floes from the marginal seas of Siberia or the North American Arctic to reach the Fram Strait, where they melt.

Conversely, this means that sea ice transports large quantities of microplastic to the waters off the northeast coast of Greenland, according to the press release.

The researchers are uncertain whether the released plastic particles subsequently remain in the Arctic or are transported farther south. However, it seems likely that the plastic litter begins sinking into deeper waters relatively quickly.

The findings highlight that even remote areas of the world ocean are not spared by this type of pollution.

Most of the plastic in the sea ice traveled long range from highly polluted areas and some localized sources.

It shows that “what enters the ocean and does not degrade will finally be found everywhere,” even in Arctic sea ice, according to Peeken.

In most studies, the studied area was inspected by light microscopy and suspected microplastic particles were then analyzed individually by Fourier transform infrared (FTIR) microscopy.

"Imaging FTIR involves far more informative infrared region of the spectrum from the very onset of the analysis. It enables the detection of very small particles (11 micrometers), which are most likely overlooked by visual inspection," Peeken said.

In contrast, this study used FTIR-imaging and scanned entire areas. This likely excluded the human bias introduced by visual selection of particles, according to Peeken.

While the impact of this microplastic is largely unknown, researchers are working to discover the effects of the microplastic on the environment, ocean species and humans.

“Since the particles are very small, they could easily be ingested by arctic microorganisms like ciliates, but also by small copepods living in the ice,” Peeken said.

Particularly when subjected to the even smaller nanoplastic particles, this can lead to reactions such as inflammations or even changes in the behavior of fish.

However, there are other studies that show the particles are just excreted after ingestion without any harm.

Studies have also shown that toxins accumulate on microplastic, which in turn can be harmful to the animals receiving them, Peeken said.

In addition, these particles also serve as transport vehicles for organisms to distant areas where they are not necessarily native. Thus, they can change the biodiversity of existing biological communities.

“Overall, pollution with plastic waste is likely to have far-reaching consequences for marine ecosystems but also for humans as end users of marine food,” Peeken said.

However, a precise assessment of the actual consequences cannot yet be given, Peeken added.

“We need to close the 'plastic tape' to the ocean. I think we have to change our careless use of plastic products and start to choose more environmental friendly alternatives,” Peeken said.

There are several techniques to reduce your plastic imprint, and every single person can do this.

Policymakers and companies are also requested to come up with solutions. For example, by banning certain products, such as harmful microbeads in soaps and toothpastes, or by enhancing the production of biodegradable plastic substitutes.

Reducing microplastic and plastics worldwide will help to mitigate the impacts, according to Peeken.

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