Last updated April 26, 2018 at 9:24 am
It’s depressing but probably not surprising to learn that there is more microplastic in Arctic sea ice than ever before.
Credit: The Crimson Monkey/iStock
Many of the particles of plastic in the Arctic sea ice are so small that they could easily be ingested by arctic microorganisms, and that has scientists particularly concerned.
“No one can say for certain how harmful these tiny plastic particles are for marine life, or ultimately also for human beings,” biologist Dr Ilka Peeken notes.
Peeken and colleagues from the Helmholtz Centre for Polar and Marine Research gathered ice samples from five regions during three expeditions over the spring and summer of 2014/15.
Transpolar drift and the Fram Strait
All samples were along the Transpolar Drift and the Fram Strait, which transports sea ice from the Central Arctic to the North Atlantic.
These samples were found to contain up to 12,000 microplastic particles per litre of ice. More than half of the particles were less than a twentieth of a millimetre wide. Two-thirds belonged to the smallest-scale category of microplastic – “50 micrometres and smaller”.
Microplastic refers to plastic particles, fibres, pellets and other fragments with a length, width or diameter ranging from a few micrometres to under five millimetres.
A considerable amount of microplastic is released directly into the ocean by the gradual deterioration of larger pieces of plastic, but it can also be created on land, such as when synthetic textiles are washed or car tyres abrade.
Paint and nylon, too
The researchers say the different types of plastic showed a unique footprint in the ice allowing them to trace them back to possible sources.
For example, the high percentage of paint and nylon particles pointed to the intensified shipping and fishing activities in some parts of the Arctic Ocean.
They were the first to analyse the ice cores layer by layer using a Fourier Transform Infrared Spectrometer, 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.
And don’t forget the cigarette butts
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.
“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,” Peeken said.
In all, the researchers found 17 different types of plastic in the sea ice, including packaging materials like polyethylene and polypropylene, as well as paints, nylon, polyester and cellulose acetate – the latter primarily used in the manufacture of cigarette filters.
They can’t yet say whether the released plastic particles subsequently remain in the Arctic or are transported farther south; in fact, it seems likely that the plastic litter begins sinking into deeper waters relatively quickly.
The paper published in Nature Communications.
