Sunlight and Seawater Break Down Synthetic Fabrics into Microfibers Polluting Oceans

Sunlight and Seawater Break Down Synthetic Fabrics into Microfibers Polluting Oceans
by Riko Seibo
Tokyo, Japan (SPX) Oct 30, 2025

A team of scientists from the Chinese Research Academy of Environmental Sciences and Nanjing University of Information Science and Technology conducted experiments to analyze how common polyester textiles degrade when exposed to sunlight in coastal seawater. Their study simulated environmental conditions to observe the release of microscopic plastic fibers-known as microfibers-over time.

The researchers placed samples of colored polyethylene terephthalate (PET) fabrics into seawater and exposed them to ultraviolet light in laboratory conditions for 12 days, representing about one year of natural sunlight exposure. Their findings showed that just 0.1 grams of purple PET fabric emitted close to 47,400 microfibers, while green, yellow, and blue fabrics released between 14,400 and 37,020 microfibers in the same time frame.

Advanced imaging revealed structural damage to the fabric surface, including roughened threads, fragmentation, and visible cracks. The study confirmed that darker colors, particularly purple, promote faster degradation due to higher absorption of light energy by the dyes. This triggered increased production of reactive oxygen species such as hydroxyl radicals (measured up to 6.2 + 10?5 molar for purple fibers), which speed up the breakdown of plastic molecules and generate more microfibers.

Microfibers shed from textiles are finer than a human hair. Once in the ocean, these particles persist and are consumed by marine organisms, posing risks to both ecosystems and human health via bioaccumulation in the food chain.

Co-author Dr. Xiaoli Zhao stated, "Sunlight acts as a slow but powerful scissor. Our results show that the colors and dyes used in fabrics can influence how quickly they degrade and release microfibers into the ocean." Dr. Xiaowei Wu observed, "Textile color and dye chemistry are not just aesthetic choices. They can directly affect how much microplastic ends up in the ocean."

The findings point toward the need for textile manufacturers to factor in light absorption by dyes when considering microfiber pollution reduction. Future studies will focus on how biofouling, ocean currents, and fabric composition further affect microfiber behavior in marine settings.

Research Report:Polyethylene terephthalate microfiber release from textiles in coastal seawater ecosystems under sunlight-driven photochemical transformation