New research has shown the existence of record amounts of microplastics in Arctic sea ice. Microplastics, refer to plastic particles, fibres, pellets and other fragments with a length, width or diameter ranging from only a few micrometres – thousandths of a millimetre – to under five millimetres. These occur in the ocean primarily as the result of the gradual breakdown of larger pieces of plastic. Estimates suggest about eight million tonnes of plastic move from the land into the ocean every year ¹.
Published in Nature Communications this week, the study conducted by researchers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) sampled ice from five Arctic Ocean regions and found up to 12,000 microplastic particles per litre (approximately 1.06 liquid quarts) of ice. Overall, traces of 17 different types of plastic were found in the frozen seawater, and the differing types of plastic showed a unique footprint in the ice allowing the researchers to trace them back to possible sources.
In order to determine the exact amount and distribution of microplastic in the sea ice, the AWI researchers were the first to analyse the ice cores layer by layer using a Fourier Transform Infrared Spectrometer (FTIR), a device that bombards microparticles with infrared light and uses a special mathematical method to analyse the radiation they reflect back. Depending on their makeup, the particles absorb and reflect different wavelengths, allowing every substance to be identified by its optic fingerprint.
The types of plastic discovered during the study included particularly high concentrations of polyethylene particles. Polyethylene is primarily used in packaging material. “Accordingly, we assume that these fragments represent remains of the so-called Great Pacific Garbage Patch and are pushed along the Bering Strait and into the Arctic Ocean by the Pacific inflow.”
Other plastic particles found included high concentrations of paint particles from ship’s paint and nylon waste from fishing nets in ice from the shallow marginal seas of Siberia.
“These findings suggest that both the expanding shipping and fishing activities in the Arctic are leaving their mark. The high microplastic concentrations in the sea ice can thus not only be attributed to sources outside the Arctic Ocean. Instead, they also point to local pollution in the Arctic,” says AWI biologist and first author DR Ilka Peeken
Also found were traces of nylon, polyester, and cellulose acetate (which is primarily used in the manufacture of cigarette filters).
“During our work, we realised that more than half of the microplastic particles trapped in the ice were less than a twentieth of a millimetre wide, which means they could easily be ingested by arctic microorganisms like ciliates, but also by copepods,” says Dr Peeken. The observation is a very troubling one because, as she explains, “No one can say for certain how harmful these tiny plastic particles are for marine life, or ultimately also for human beings.”
With ocean temperatures rising across the globe and the increase in sea ice melting, these microplastics are destined to eventually be released back into the ocean.
“As climate change will accelerate sea ice melting, more microplastics will be released from the sea ice and will enter the marine environment,” said Dr Pennie Lindeque, lead plastics scientist at Plymouth Marine Laboratory.
Microplastics have long been recognised as a growing environmental hazard and the occurrence of these particles in some of the most remote regions on Earth is certainly a worrying sign.
Ilka Peeken, Sebastian Primpke , Birte Beyer, Julia Guetermann, Christian Katlein, Thomas Krumpen, Melanie Bergmann, Laura Hehemann, Gunnar Gerdts: Arctic sea ice is an important temporal sink and means of transport for microplastic, Nature Communications, DOI: 10.1038/s41467-018-03825-5
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