Microplastics in Arctic sea ice — ‘nowhere is immune’

PARIS: Researchers warned Tuesday of a “troubling” accumulation of microplastics in sea ice floating in the Arctic ocean, a major potential source of water pollution as global warming melts the sheets of frozen water.

A team from the Alfred Wegener Institute for Polar and Marine Research (AWI) found 17 different plastic types in ice samples gathered during three Arctic expeditions on board the research icebreaker Polarstern in 2014 and 2015.

They included plastic from shopping bags and food packaging, from ship paint, fishing nets, nylon and polyester found in synthetic fabrics, and cigarette filters.One sample contained the highest concentration of microplastics ever found in sea ice — up to 12,000 particles per litre of frozen water.

This was two- to three times higher than any past measurement, the research team wrote in the journal Nature Communications.The discovery suggests microplastics “are now ubiquitous within the surface waters of the world’s ocean,” sea ice physicist Jeremy Wilkinson of the British Antarctic Survey said in a comment on the study.

“Nowhere is immune,” he said via the Science Media Centre in London.Sea ice grows from the freezing of seawater directly underneath the existing ice, thus incorporating floating microplastics as it grows downward, he explained.

This means the plastics were present as the ice was growing, and drifting, in the Arctic Ocean.Of particular concern was the particles’ small size.Some were only 11 micrometres across — about a sixth the diameter of a human hair, the team said. A micrometre is a millionth of a metre.

This “means they could easily be ingested by Arctic micro-organisms” such as small crustaceans on which fish feed,” said study coauthor Ilka Peeken, an AWI biologist.“No-one can say for certain how harmful these tiny plastic particles are for marine life, or ultimately also for human beings,” she said.Micro-plastics are less than five millimetres (0,2 inches) long, about the size of a sesame seed.