Credit: Gualtiero Boffi | Dreamstime.com

By the time I take the last steps to the car on Vancouver Island’s Bedwell Lakes Trail, I’ve been hiking in the same polypropylene base-layer for three days.

The second I pull the shirt off, I smell freedom from the VBO (very bad odour). Later, I chuck it into the laundry and feel like I’m doing the world a favour. I’m not. 

Washing this synthetic shirt will unleash thousands of tiny bits of plastic into the water system. Many will float downstream into the ocean, travel around on currents, get gobbled up by microorganisms, climb the food chain and accumulate in fish, birds and other marine animals, impacting their immune and endocrine systems.

That’s the nightmarish secret afterlives of the lint falling off our clothing, according to a growing collection of research. While every shirt, sock and pant erodes every time it’s washed—wool, cotton and other natural fibres biodegrade. The micro-sized (defined as less than five millimetres) bits of plastic shed by nylon, polypropylene and acrylic clothing do not. Most slip through the filtering process of sewage treatment plants.

“We do know some marine animals ingest plastics, even down to mollusks like mussels and clams,” says Courtney Arthur, a research coordinator with the U.S. National Oceanic and Atmospheric Administration. “We know it’s possible they could be accumulating in the food chain. All spectrum of marine life has the potential to take in these small particles, but at this point, it’s hard to say how much harm is being done.”

Arthur says scientists have known about plastics in the ocean for a while, but the focus was on larger pieces of garbage like disposable water bottles and tiny plastics used in toothpaste and face-wash. Then ecologist Mark Browne, from the University College Dublin, collected sand samples from 18 beaches on six continents. Every sample contained micro-plastics and 80 per cent were polyester or acrylic. When he tested the wastewater from washing a single fleece jacket, he found 1,900 fibres. Other studies have backed up his findings and shown that micro-plastic fibre concentrations are highest near where humans live.

Bottom line, your indispensable fleece is probably killing the ocean. What should an environmentally conscious, non-body-odour loving person to do? Switching to natural fibres, like wool, is an option. But even these have issues. For instance, chlorine is often used to make wool less itchy. Cotton uses more water and tons of fertilizer. And sometimes polypropylene is the best choice for the job. That’s why the Outdoor Industry Association Sustainable Working Group, representing 250 companies, is working with the Ocean Conservancy to better understand the issue. Until they figure something out, the easiest thing—and maybe the only thing—to do is wash plastic clothing less. 

How often? There’s no magic number, but speaking as a fellow trail user, three days for that polypro base layer is probably too many.