Study Shows Synthetic Clothing Microfibers Account for Major Pollution

According to a new study, 176,500 metric tons of synthetic microfibers—mainly nylon and polyester—are discharged into terrestrial environments every year around the world.

The study was published in the open-access journal PLOS ONE by Jenna Gavigan and collaborators from the University of California at Santa Barbara.

These microfibers detach from clothing during washing, and the quantity that ends up on land currently surpasses the quantity that enters water bodies.

Plastic pollution in the ocean has recently attracted a great deal of attention. However, waterways are not the sole place in which plastic gets accumulated. A total of 14% of all plastic is used for making synthetic fibers, mainly for clothing.

Microfibers, which are particles measuring less than 5 mm in length, are produced in huge quantities at each stage of a fiber’s life cycle, particularly during washing, which mechanically breaks down the synthetic fibers.

However, when wash water becomes a part of the flow to a wastewater treatment plant, the microfibers present in this flow may be retained together with biosolid sludge, which may be buried in landfills or used on cropland.

To gain a deeper insight into the scope and distribution of the synthetic microfibers at a global level, the study’s authors gathered information on the worldwide production, consumption, and discharge of plastics, integrating additional data on microfibers discharged during washing both by hand and by machine, and the fate of the wastewater sludge containing much of this plastic waste and the buildup and distribution of microfibers in wastewater treatment plants.

Since several areas lack a comprehensive data on wastewater treatment, the study’s authors estimated where it is necessary to create a detailed picture, utilizing median income as a proxy for the potential level of wastewater treatment.

The information does not indicate the entire emissions generated from clothing all through its lifetime—for instance, secondhand clothing is not considered.

But according to the authors' calculations, around 5.6 million metric tons of synthetic microfibers were discharged from apparel washing between 1950, the beginning of the extensive use of synthetic fibers, and 2016—50% of it in the last one decade.

Almost 50% of synthetic microfibers ended up on land, either on the landfills (0.6 million metric tons) or on the surface (1.9 million metric tons). Emissions are increasing 12.9% every year, and present annual emissions to land (176.5 thousand metric tons annually) surpass those to water bodies (167 thousand metric tons every year).

Large-scale removal of microfibers from the environment is unlikely to be technically feasible or economically viable, so 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.

Jenna Gavigan, University of California, Santa Barbara

The study was financially supported by Ocean Conservancy, Purnell, and the Outdoor Industry Association Microfiber Research Cohort; S.S. acknowledged the financial support of the US Environmental Protection Agency’s Science to Achieve Results Program under Grant No. 83557907; and the authors expressed their thanks to H. William Kuni for his substantial support for TK’s and RG’s involvement through the H. William Kuni Interdisciplinary Fellowship.

Journal Reference:

Gavigan, J., et al. (2020) Synthetic microfiber emissions to land rival those to waterbodies and are growing. PLOS ONE. doi.org/10.1371/journal.pone.0237839.