Pollutants may wind up in Arctic food chain as climate warms, ice melts

Arctic sea ice has sopped up and stored large quantities of microplastic pollution from populated areas in the south, a new study has found.

Microplastics are tiny pieces of plastic from microscopic to fingernail-sized that have been found polluting oceans and lakes around the world over the past decade, but not so far north as the Arctic Ocean. Scientists are concerned about them because they tend to suck up and concentrate other pollutants in the environment, which enter the food chain when animals swallow microplastics.

Rachel Obbard, a materials scientist at Dartmouth in New Hamphire, discovered that Arctic sea ice was contaminated with microplastics by accident when she melted the ice in order to count diatoms – microscopic algae that live under the ice.

"I was really shocked and saddened," she told CBC's Quirks & Quarks in an interview that airs Saturday. "I guess I, like most people, still consider the Arctic to be a pristine and remote area and clearly, our pollution has reached even it."

When the melted ice was filtered, the filter paper trapped not just sand and diatoms, but also a variety of brightly coloured particles. (Y.-Q. Wong and A. Khitun/Dartmouth College)

"I saw a lot of small threads, some solid chunks in oranges and reds, and a bunch of small blue nodules," Obbard recalled.

Microplastics were found in all ice cores taken from four different locations in the Arctic that were far apart, suggesting that the microplastic contamination is widespread.