More Synthetic Microfibers Now End up on Land Than in Water

They're spread on farmers' fields in the form of biosolid sludge.

brightly colored leggings

@akaimade via Twenty20

Many of us are now aware that synthetic microfiber pollution is a real problem. Thanks to extensive reporting in recent years, the release of synthetic fibers from laundry into the natural environment has gone from being "the biggest environmental problem you've never heard of" (as one ecologist called it back in 2011) to something that's on the personal radar of most moderately-informed adults.

But just how big a problem is this form of pollution? A group of researchers from the Bren School of Environmental Science and Management at the University of California, Santa Barbara, set out to quantify the situation in a new open-access study published in the journal PLOS One. What they found was that, between 1950 (when synthetic clothing was first created) and 2016, an estimated 5.6 Mt (million metric tons) have been emitted from apparel washing worldwide, with half of it being generated in just the past decade.

Synthetic fabrics comprise 14 percent of global plastics production, and microfibers are generated when these fabrics degrade and shed fibers of 5 millimeters in length or less. This occurs most dramatically when the fabric is washed, although it happens at all stages of production, too, from manufacturing to wearing to disposal. For this study, the researchers tried to get a comprehensive picture of how many people wash clothes in machines (top- vs. front-loading) or by hand, what quantities of synthetic garments people own on average, and what their lifespan is. It did not take into consideration the secondhand clothing market, which prolongs the use of many garments and contributes to further microfiber pollution, particularly as garments degrade with age; there wasn't enough data to account for it properly.

The researchers explained how the pollution occurs:

"Laundry effluent conveys microfibers into wastewater streams and is either processed by wastewater treatment plants or emitted directly into the natural environment. [These plants] can remove up to 98–99% of microfibers which are then retained in biosolids. Biosolids are commonly used as soil amendments [fertilizer], providing a route for synthetic microfibers into terrestrial environments where they can remain detectable in soils for up to fifteen years after application. Microfibers that are not removed during treatment typically fall within the smallest size range and are ejected into receiving fresh or marine waterbodies."

What this study revealed is that terrestrial environments have now surpassed marine environments as the primary destination for microfibers, despite the fact that ocean plastic pollution receives more media attention than land-based pollution. The authors wrote that, while waterbodies have received more microfiber pollution in the past, "annual emissions to terrestrial environments and landfill combined are now exceeding those to waterbodies." The former is calculated to be around 176,500 metric tons of microfibers annually, compared to 167,200 metric tons entering waterbodies.

Relatively little is known about the effects of synthetic microfibers being spread on the land as a fertilizer component or disposed in landfill, but it does open doors for further contamination: "The microfibers initially emitted to terrestrial environments have the potential to eventually enter other compartments, including waterbodies and biota, through runoff, resuspension, or convection over a long period of time."

Removing microfibers from the soil (or waterways) is not a feasible solution; the scale is too vast. As lead study author Jenna Gavigan said in a press release, the focus needs to be on emission prevention: "Since wastewater treatment plants don't necessarily reduce emissions to the environment, our focus needs to be reducing emissions before they enter the wastewater stream."

How Do We Do That?

Installing filters or using microfiber-trapping devices (such as the Guppy Bag or a Cora Ball) in washing machines would be a good place to start, although the lint must still be disposed of and would likely end up in landfill or an incinerator – neither of which is ideal, but arguably better than spreading contaminated sludge on agricultural fields. Re-engineering synthetic fabrics to shed less would be great, but is perhaps somewhat of a pipe dream at this stage. Encouraging people to purchase more natural, biodegradable materials such as cotton, wool, and hemp would help, as would more hand-washing, cold water, hang-drying, and less frequent laundering overall; airing out between wears helps. See here for more pointers on how to reduce microfiber shedding.

It's not an easy problem to fix, especially with people's great love of stretchy leisure clothes, but it's important to realize that improving wastewater filtration does not make the problem go away. Study co-author and industrial ecologist Roland Geyer put it well to the BBC:

"I hear people say that the synthetic microfiber problem from apparel washing will take care of itself as wastewater treatment works become more widespread around the world and more efficient. But really what we're doing is just moving the problem from one environmental compartment to another."

If it's not in the water, then it's in the soil – or it's being burned and sent up into the atmosphere in the form of gas. We need to rethink how we shop, dress, and consume, because clearly the current approach isn't working.