Mystery of 'Missing Plastics' Solved in Arctic Ice

So about the hundreds of millions of tons of plastics we've been releasing into the oceans—it went where, exactly? According to a new study, much of it was trapped in Arctic ice and will be released as the ice melts, USA Today reports. At current melting rates, more than 1 trillion pieces of microplastic—like fibers, polymer beads, and fragments under 5 millimeters in length—will reach Earth's oceans over the next decade. "It was such a surprise to me to find them in such a remote region," co-author Rachel Obbard tells Science. "These particles have come a long way."

Obbard and her colleagues based their figures on ice cores taken over two expeditions and analyzed under a microscope. What they found: 54% rayon (not technically a plastic, since it's wood-based, but it's still a "manmade semi-synthetic"), along with polyester (21%), nylon (16%), polypropylene (3%), and others in smaller amounts. So should we worry? Scientists don't know yet, but a California ecologist has studied how plastics can remain in the tissues of marine organisms and possibly release pollutants upon ingestion. "We’re starting to worry a bit more," he says. (More plastic stories.)