Are We Eating Our Fleece Jackets? Microfibers Are Migrating Into Field And Food

The innovation of synthetic fleece has allowed many outdoor enthusiasts to hike with warmth and comfort. But what many of these fleece-wearing nature-lovers don't know is that each wash of their jackets and pullovers releases thousands of microscopic plastic fibers, or microfibers into the environment — from their favorite national park, to agricultural lands, to waters with fish that make it back onto our plates.

This has scientists wondering: are we eating our sweaters' synthetic microfibers?

Probably, says Chelsea Rochman, an ecologist and evolutionary biologist at the University of Toronto, St. George. "Microfibers seem to be one of the most common plastic debris items in animals and environmental samples," Rochman says.

In fact, peer-reviewed studies have shown that these synthetic microfibers — a type of plastic smaller than a millimeter in length and made up of various synthetic polymers — have popped up in table salt in China, in arctic waters and in fish caught off the coast of California. These tiny fibers make up 85 percent of human debris on shorelines across the globe, according to a 2011 study. They're basically inescapable. So it's not unlikely they're finding their way into the human diet, especially in seafood.

In an effort to increase transparency and minimize pollution from their products, California-based clothing company Patagonia, popular for their microfiber-containing vests, pullovers, and jackets, has started to partner with research groups to get to the bottom of how these fibers might be affecting both wildlife and human health.

Last year, the company worked with a research group led by Patricia Holden, a professor of environmental microbiology at University of California, Santa Barbara, on a study to quantify microfiber release in washing machines. The group ran both name-brand and off-brand polyester fleece jackets through the wash without detergent to get a handle on the mass of microfibers shed each time.

The results, published in September of last year in Environmental Science and Technology, were eye-opening. Each wash of a jacket shed microfibers up to two grams. (For reference, a paperclip weighs 1.5 grams.) Also, each fleece jacket released seven times more fibers when washed in a top-load washing machine versus a front-load.

The dryer traps extra fuzz in the lint filter, says Holden. "But in the washer, they're carried down the drain." From there, they end up in wastewater treatment plants, where many fibers can't be filtered out, and are released into the environment. Holden notes that this is just one pathway microfibers take into the environment. There could be additional pathways that scientists have yet to understand, she says.

And then there is the larger question: are these tiny synthetic fibers harmful to humans and wildlife?

The answer is still fuzzy. Some research shows certain wildlife might be affected: two studies showed that ingesting microfibers leads to increased mortality in water fleas and makes common crabs eat less food overall. But it's unclear what effects, if any, they have on you and me.

So the question for us is: Do we choose to eat seafood, knowing that we'll probably get a few microfibers woven in? Or do we quit seafood altogether at the chance that they could have adverse health effects?

"I have no doubt that every time I eat oysters and mussels I eat at least one microfiber," says Rochman, who studies microplastics in marine habitats and continues to indulge in seafood. "I see dust in the air and we inhale that. The question is, at what point does it become a problem? Here, the benefits outweigh the costs."

Gregg Treinish, founder and executive director of the non-profit Adventurers and Scientists for Conservation, has a different take. "If you're eating fish, you're eating plastic," Treinish says. "There's no proven causal relationship with health issues, but I don't want to spend the next 50 years eating it and then learn I shouldn't have been."

Holden, Rochman, Treinish, and others all agree that we don't understand everything about how microfibers traverse ecosystems and what they do inside human and wildlife bodies. But to minimize pollution in the first place, there are short-term solutions we can adopt.

Treinish rigged his washing machine with a filter designed for septic systems, hoping to catch some microfibers before they escape into the waterways. So far, he's filled two Nalgene water bottles with the filtrate. He continues to use the filter.

And he suggests a simpler solution: just wash your fleece less often. "Obviously I'll wash my jacket if a kid throws up on it," Treinish says, "but not if I just wore it once. It's important what individuals do. I hope that doesn't get lost."

Copyright 2017 NPR.