The most common microplastics in the environment are microfibers—plastic fragments shaped like tiny threads or filaments. Microfibers come from many sources, including cigarette butts, fishing nets and ropes, but the biggest source is synthetic fabrics, which constantly shed them.
Textiles shed microfibers while they are manufactured, worn and disposed of, but especially when they are washed. A single wash load can release several million microfibers. Many factors affect how many fibers are released, including fabric type, mechanical action, detergents, temperature and the duration of the wash cycle.
My research focuses on coastal ecology and water pollution, including work in New York and New Jersey marshes and estuaries that are heavily affected by human activities. Here are some things to know about reducing microplastic pollution from your washing machine.
From fabric to water and soil
Once garments release microfibers in washing machines, the fibers enter the wastewater stream, which generally goes to a wastewater treatment plant. Advanced treatment plants can remove up to 99% of microfibers from water. But since a single laundry load can produce millions of fibers, treated water discharged from the plant still contains a huge number of them.
Microfibers that are removed during treatment end up in sewage sludge—a mix of solid materials that is processed to remove pathogens. In many cases, treated sewage sludge is applied to soil as a fertilizer. This allows microfibers to enter air and soil, and to be transferred to soil organisms and up the terrestrial food web or taken up by crops.
Microplastics that wash into rivers, lakes and bays can have many harmful effects. They may be consumed by fish and other aquatic animals, affecting their biochemistry, physiology, reproduction, development or behavior. These microplastics contain chemical additives, including substances like phthalates and bisphenol A that can leach out and may have health effects in humans and animals, including effects on the endocrine system.
Textile microfibers also contain additional chemicals that have been shown to be toxic, such as fabric dyes, anti-wrinkle agents and flame retardants. In addition, contaminants that are present in the water, such as metals and pesticides, can stick to microplastic particles, turning them into a veritable cocktail of contaminants that may be transferred into animals that eat them.