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Trillions of Plastic Pieces May Be Trapped in Arctic Ice

May 28, 2014   |   by Eric Hand   |   Science

Humans produced nearly 300 million tons of plastic in 2012, but where does it end up? A new study has found plastic debris in a surprising location: trapped in Arctic sea ice. As the ice melts, it could release a flood of floating plastic onto the world.

Scientists already knew that microplastics—polymer beads, fibers, or fragments less than 5 millimeters long—can wind up in the ocean, near coastlines, or in swirling eddies such as the Great Pacific Garbage Patch. But Rachel Obbard, a [professor of engineering and] materials scientist at Dartmouth, was shocked to find that currents had carried the stuff to the Arctic.

In a study published online this month in Earth’s Future, Obbard and her colleagues argue that, as Arctic ice freezes, it traps floating microplastics—resulting in abundances of hundreds of particles per cubic meter. That’s three orders of magnitude larger than some counts of plastic particles in the Great Pacific Garbage Patch. “It was such a surprise to me to find them in such a remote region,” she says. “These particles have come a long way.” ...

... Obbard and her colleagues based their counts on four ice cores gathered during Arctic expeditions in 2005 and 2010. The researchers melted parts of the cores, filtered the water, and put the sediments under a microscope, selecting particles that stood out because of their shape or bright color. The particles’ chemistry was then determined by an infrared spectrometer. Most prevalent among the particles was rayon (54%), technically not a synthetic polymer because it is derived from natural cellulose. The researchers also found polyester (21%), nylon (16%), polypropylene (3%), and 2% each of polystyrene, acrylic, and polyethylene. Co-author Richard Thompson, a marine biologist at the University of Plymouth in the United Kingdom, says it’s difficult to pinpoint the source of these materials. Rayon, for instance, can be found in clothing, cigarette filters, and diapers.

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