Laundering synthetic garments made from polyester can cause them to release hundreds of thousands of microplastics per wash cycle. A new first-of-its-kind study shows that simply wearing them, however, can slough off even more over time.
While a gram of polyester fabric might discharge up to 4,000 tiny fibers during a single conventional wash cycle, according to the study, that same material could shed a similar amount with just three hours of normal activity.
Scaled up, the results indicate that a person could discharge nearly 300 million polyester microfibers per year to the environment by washing their clothes, and more than 900 million to the air by wearing them. The numbers were published this week in the journal Environmental Science and Technology.
“More evidence has been accumulating on the presence of synthetic microfibers not only in aquatic environments, but also in atmospheric ones,” Francesca De Falco, a research fellow at the Institute for Polymers, Composites and Biomaterials of the National Research Council of Italy (IPCB-CNR) and lead author of the paper, said in a statement. “That is why we decided to design this set of experiments to study microfiber release by garments to both media.”
Scientists from IPCB-CNR and the University of Plymouth took four different items of polyester and polyester-blend clothing, washed them at 40 degrees Celsius and collected any released fibers. They found that between 700 and 4,000 individual fibers were offloaded per gram of fabric during a single wash cycle.
They then placed multiple volunteers wearing versions of each of the four garments in a dedicated clean lab and asked them to perform a sequence of movements mirroring real-life activity. An estimated 400 fibers were released per gram of fabric in only 20 minutes.
Overall, the polyester-cotton garment released the most microfibers during both washing and wearing, while the woven polyester one shed the fewest, they found. Textiles with compact structures or highly twisted and continuous-filament yarns also released fewer microfibers to both air and water.
Based on their results, the researchers say previous estimates of microplastic pollution may be lower than reality, since they don’t take into account quantities released directly in to the air. Indeed, one recent study discovered that 92 percent of microplastics in London’s air are “fibrous microplastics” from abraded plastic textiles such as clothing, upholstery and carpets.
“The key story here is that the emission of fibers while wearing clothes is likely of a similar order of magnitude as that from washing them,” said Richard Thompson, head of the University of Plymouth’s International Marine Litter Unit and a senior author of the study.
On the other hand, the results also show that textile design can “strongly influence” both release to the air and during laundry.
“That is a crucial message highlighting the importance of sustainable design for the fashion industry,” he said. “Indeed, many of the current issues associated with the environmental impacts of plastic items stem from a lack of holistic thinking at the design stage.”
As many as 51 trillion microplastic particles inundate the seas, according to the United Nations Environmental Programme. The Institution of Mechanical Engineers estimates that more than one-third originate from synthetic textiles.
Microplastics, which are often mistaken by marine life as food, have been uncovered in the gastrointestinal tracts of fish, turtles and whales, in most drinking water, in rain, snow and Antarctic ice, in flying insects, the majority of table salt and even human stool. According to a study commissioned by the World Wildlife Fund last year, people are eating, swallowing or breathing in roughly 2,000 minuscule pieces of plastic every week, an amount equal to the weight of a credit card.