By simply washing your clothes, you might be flooding the oceans with plastic pollution, a new study showed. Researchers found that nearly three-quarters of the microplastics in the Arctic seawater were polyester fibers, which are most likely coming from textiles manufacturing and household laundry.

Millions of tons of plastic enter marine ecosystems every year, and quantities are expected to increase in the coming years. Over time, plastic items in the ocean can break down into smaller pieces, known as microplastics. They can be the size of a rice grain or even smaller, making them easy to be ingested by sea creatures.

These very small pieces of plastic are literally all over the place, even on some of the world’s most seemingly unaccessible regions. Scientists are frequently finding them in the most remote regions of the world such as the Pyrenees mountains between France and Spain or the chilling Arctic sea. But questions remain regarding where this severe plastic contamination is actually coming from.

Researchers from Canada’s Department of Fisheries and Oceans and the Ocean Wise conservation group sampled seawater from the Arctic and found that synthetic fibers accounted for 92% of the plastic pollution. Of this, 73% was polyester, which resembles the dimensions and chemical identities of synthetic textiles.

“The striking conclusion here is that we now have strong evidence that homes in Europe and North America are directly polluting the Arctic with fibers from laundry (via wastewater discharge),” lead author Peter Ross told AFP, adding that ocean currents are playing a big role in moving the fibers northwards to the Arctic.

Ross and his team gathered near-surface seawater samples from a 19,000-kilometer section from the city of Tromso in Norway to the North Pole, through the Canadian Arctic, and into the Beaufort Sea. They looked at samples up to a depth of around 1,000 meters. All had microplastics except one, which shows the extent of the problem.

The researchers worked with microscopy and infrared analysis to identify and measure the microplastics. They found almost three times more microplastic particles in the eastern Arctic compared to the west, which supports the idea that the polyester fibers could be arriving at the east of the region by the Atlantic.

Ocean Wise has done tests on washing machines in the past, finding that a single item of clothing can release millions of fibers during a normal domestic wash. They also warned that wastewater treatment plants often don’t catch the plastic fibers, with households in the US and Canada releasing almost 900 tons of microfibers per year.

“The textile sector can do much to design more sustainable clothing, including by designing clothes that shed less,” Ross told AFP. Governments have to make sure wastewater treatment plants have installed technologies to remove microplastics, while households should choose products with more environmentally-friendly fabrics, he added.

A study in 2019 found as many as 10,000 microplastics per liter of snow in the Arctic. Being small and lightweight, the microplastics are easily blown by winds which transport them over long distances through the atmosphere. Finally, they’re washed out of the atmosphere by rain or snow. This means no place on the planet is spared from our plastic pollution.

The study was published in the journal Nature Communications.