A study published in the journal Environmental Science and Technology Letters found that microfibers from jeans are polluting the oceans and lakes. In other words, the pollution has already entered the Canadian Arctic Ocean.

“It’s just a really potent example of human impact” an environmental scientist at the College of Toronto and co-author of the study says WIRED.

Plastic microfibers reach the world’s oceans and rivers through sewage treatment plants and washing machines. Therefore, one study estimates that two garbage truck microfibers enter European oceans this way every day. Therefore, these fibers are found everywhere, from the bellies of deep-sea mussels to dense hotspots in seabed sediments in the Mediterranean Sea.

Jeans are polluting the oceans and lakes, so they aren’t innocent.

About half of the world’s population wears jeans or denim clothing. So, researchers at the College of Toronto wanted to know if denim had an impact on the planet. Then, they studied water samples from the Canadian Arctic Archipelago, the Great Lakes, and suburban lakes near Toronto, and found that indigo denim microfibers make up a significant percentage of all microfibers in those locations. They also found that the new jeans removed more fibers, and one pair of jeans could release 56,000 microfibers per wash.

Read More: How to start an eco-friendly laundry routine.