Scientists have discovered that Arctic sea ice now contains record quantities of microplastic particles, many of which travel to the region from the so-called Great Pacific Garbage Patch.
Ice samples from five different locations across the Arctic contained up to 12,000 microplastic particles per litre of sea ice. Large quantities of these microplastics are released into the ocean as the result of the deterioration of larger pieces of plastic.
However, they can also be created on land through the laundering of synthetic fabrics or the abrasion of car tyres. These tiny fragments initially float through the air as dust and are then blown to the ocean by the wind, or transit through sewer networks.
To determine the concentration and distribution of microplastics, researchers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) used a Fourier Transform Infrared Spectrometer to blast the particles with infrared light. They device is then able to analyze the radiation they reflect back.
Depending upon their chemical composition, the microplastics absorb and reflect different wavelengths, allowing every substance to be identified by its optic fingerprint.
The researchers subsequently discovered 17 different types of plastic in the sea ice, including the packaging materials polyethylene and polypropylene, as well as paints, nylon, polyester, and cellulose acetate, which is a key component in cigarette filters.
“During our work, we realized 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 AWI biologist and the study’s lead author, Dr Ilka Peeken.
“No one can say for certain how harmful these tiny plastic particles are for marine life, or ultimately for human beings.”
The scientists also found that the ice floes driven in the water masses of the Canadian Basin contain unusually high concentrations of polyethylene packaging. They believe these particles originate in the Great Pacific Garbage Patch and are pushed along the Bering Strait and into the Arctic by the Pacific inflow.
In the shallower seas of Siberia, the team discovered particles of hull coating and nylon waste from fishing nets. These findings suggest that the expansion of shipping and fishing activities in the region is having an impact on the environment.
“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 Peeken.