Researchers have recently found higher amounts of microplastic in Arctic sea ice than ever before, with samples containing up to 12,000 microplastic particles per litre of sea ice.
Researchers at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), Germany, conducted the study and found that most particles discovered in the Arctic sea ice were microscopically small, however, these particles showed a unique footprint.
The different types of plastic showing a unique footprint allowed the researchers to trace them back to possible sources, this includes the litter in the ocean and a high percentage of paint and nylon products pointing to the intensified shipping and fishing activities.
The AWI research team had gathered ice samples over the course of three expeditions to the Arctic Ocean on board the research icebreaker, Polarstern. The samples were sourced from five regions along the Transpolar Drift and the Fram Strait, which transport sea ice from the Central Arctic to the North Atlantic.
Dr Ilka Peeken, AWI biologist said: “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.
“No one can say for certain how harmful these tiny plastic particles are for marine life, or ultimately also for human beings.”
With large amounts of plastics working their way into the ocean, the gradual deterioration means that more and more microplastic particles are being found. However, these particles can also be created on land, for example: Laundering textiles or abrasion of car tyres, which are dust particles initially, finding their way into the ocean.
For the research to determine the amount of microplastic particles in the Arctic sea ice, the AWI researchers needed to analyse the ice cores layers. To do so they used a Fourier Transform Infrared Spectrometer (FRIT), which is, according to AWI, a device that loads microparticles with infrared light and uses a mathematical method to analyse the radiation they reflect back.
Depending on their makeup, the microplastic particles absorb and reflect different wavelengths, allowing every substance to be identified by its optic fingerprint.
Regions of origin
The particle density and composition varied significantly from sample to sample. At the same time, the researchers determined that the plastic particles were not uniformly distributed throughout the ice core.
Peeken said: “We traced back the journey of the ice floes we sampled and can now safely say that both the region in which the sea ice is initially formed and the water masses in which the floes drift through the Arctic while growing, have an enormous influence on the composition and layering of the encased plastic particles,”
A total of 17 different types of plastic in the Arctic sea ice, including:
- Packaging materials such as polyethylene and polypropylene;
- Polyester; and
- Cellulose acetate.