Sea ice can capture huge amounts of microscopic plastic pollution, transport it across the Arctic and dump it into the ocean as climate change causes melting, according to a new study.
Scientists from the Alfred Wegener Institute (AWI) at Helmholtz Centre for Polar and Marine Research in Germany have discovered the highest concentrations of microplastic ever found in ice cores taken from five regions throughout the Arctic Ocean.
Tests showed each litre of sea ice contained up to 12,000 plastic particles, the majority of them microscopically small.
A total of 17 types of plastic were present in the samples, with packaging materials such as polyethylene and polypropylene, plus paints, nylon, polyester and cellulose acetate, a component widely used in cigarette filters, being the most common.
The researchers said the findings are alarming as the tiny fragments can easily be eaten by the smallest marine creatures and then make their way up the food chain.
AWI biologist and study leader Dr Ilka Peeken said: “During our work we realised that more than half of the microplastic particles trapped in the ice were less than a 20th of a millimetre wide, which means they could easily be ingested by arctic micro-organisms 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.”
The researchers were also able to pinpoint possible sources of the pollution, due to the unique footprints left in the ice by different types of plastics.
Huge quantities of polyethylene found in one area are believed to have come from the massive “floating garbage patch” of plastic waste in the Pacific Ocean.
Meanwhile, high levels of paint and nylon particles have been linked to an increase in shipping and fishing in some parts of the Arctic Ocean as climate change causes sea ice to melt and opens the region to more human exploitation.
Microplastics are particles, fibres or fragments measuring less than five millimetres.
They end up in oceans via a variety of sources, including the breakdown of bigger plastic items such as fishing gear and litter, from waste water washed into the sea after laundering synthetic clothes and in dust created by car tyre friction on roads that is blown into waterways or sewers.
The study has just been published in the journal Nature Communications.