Our synthetic clothes are quietly polluting the oceans

The ocean is not where plastic belongs.
The ocean is not where plastic belongs.
Image: Reuters/Eliseo Fernandez
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Polyester and acrylic fabrics are used for all sorts of clothing, from dresses to gymwear. But they could be leaching upward of 700,000 tiny plastic fibers into the environment for each 13 lb load of laundry washed, according to new research from Plymouth University.

The study, led by PhD student Imogen Napper and professor Richard Thompson, an expert on marine debris, looked at the effects of washing clothes made of acrylic, polyester, and a polyester-cotton blend in a typical household washing machine. They chose those materials because they were readily available at retailers close to Plymouth, England, and laundered four sweaters of each, using a variety of standard washing temperatures and different cleaning products. They found synthetic fabrics can shed heavily in the wash, suggesting our laundry contributes significantly to the growing accumulation of plastic in the world’s lakes, rivers, and oceans.

For each wash load of 6 kg (about 13 lbs), the acrylic sweaters shed an estimated 729,000 fibers. Polyester let off about 496,000 fibers, and the polyester-cotton blend shed approximately 138,000. The fibers are tiny—depending on the material, they ranged from about 12 μm to 18 μm in diameter and 5mm to 8mm in length—but they collect into plastic lint that can add up over time. The type of detergent or softener, also known as conditioner, used in the wash also had an effect on the amount of fibers shed, though there was no clear trend showing that either increased or decreased shedding.

While the full effects of this sort of plastic pollution are still being studied, separate research has found that plastic bits can be harmful to aquatic life. Fish may eat the plastic instead of actual food, and absorb toxic chemicals from it. In some cases, the microplastics kill the fish before they reach reproductive age, effectively decimating populations.

But fish aren’t the only animals at risk. The plastic bits can build up in sperm whales, for instance, contributing to their deaths. And they contaminate fish consumed by humans, too. One small study of fish sold in a few local markets in the US and Indonesia found that 28% of the fish in Indonesia and 25% of the fish in US markets contained plastic debris.

The problem is great enough that the UN has warned that microplastics pose a threat to human health, while the US has banned products from using plastic microbeads—often included to make cosmetic products slightly abrasive so they work as exfoliants. A recent study found that US waterways are now basically full of microplastics. In that study, the most common type found was thin plastic fibers from textiles, which accounted for around 71% of the total plastic pollution in the samples collected.

“The quantity of microplastic in the environment is expected to increase over the next few decades,” the authors of the washing machine study say. “Due to the persistent nature of plastic contamination, there is growing awareness of the need to reduce inputs at source; this includes the direct release of microplastic-sized particles including microbeads from cosmetics, and fibres from textiles.”

In the world of clothing, that’s not likely to happen soon. Production of polyester is already outpacing cotton and wool, and it’s only expected to grow.