Sunlight turns everyday fabrics into ocean microfibers

Researchers uncover how sunlight and seawater transform synthetic textiles into microplastic pollution

Peer Reviewed Publication

Biochar Editorial Office, Shenyang Agricultural University

News Release 29-Oct-2025

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

A new study has revealed that sunlight can transform common synthetic fabrics into tiny plastic fibers that pollute coastal oceans. The findings shed light on how clothing and household textiles contribute to the growing problem of microplastic pollution in marine environments.

Scientists from the Chinese Research Academy of Environmental Sciences and Nanjing University of Information Science and Technology examined how different colored polyester fabrics break down when exposed to sunlight in seawater. They discovered that long-term exposure to ultraviolet light can convert polyethylene terephthalate (PET), a widely used textile fiber, into thousands of microscopic fragments.

After 12 days of laboratory sunlight exposure, just 0.1 grams of purple fabric released about 47,400 microfiber fragments. Green, yellow, and blue fabrics released fewer particles, at 37,020, 23,250, and 14,400 respectively. The researchers estimate that this accelerated test represents roughly one year of natural sunlight exposure in coastal waters.

“Sunlight acts as a slow but powerful scissor,” said co-corresponding author Dr. Xiaoli Zhao. “Our results show that the colors and dyes used in fabrics can influence how quickly they degrade and release microfibers into the ocean.”

The study found that darker colors, particularly purple, degraded faster because their dyes absorbed more sunlight energy and produced higher levels of reactive oxygen species such as hydroxyl radicals. These highly reactive molecules accelerate the breakdown of plastic chains, causing fibers to weaken and shed. Purple PET fibers generated about 6.2 × 10⁻¹⁵ molar hydroxyl radicals, more than those from green, blue, or yellow fibers.

The microscopic damage caused by this photoaging process was confirmed using advanced imaging techniques, showing cracks, rough surfaces, and separated threads on the fabrics. Over time, these weakened threads can fragment into smaller microfibers, which can further degrade into even tinier particles.

Microfibers, which are thinner than a human hair, are one of the most common forms of microplastic found in oceans. They can be ingested by fish, shellfish, and plankton, entering the food chain and potentially affecting marine ecosystems and human health.

The researchers emphasize that understanding how microfibers form is crucial for reducing their environmental impact. “Our study highlights that textile color and dye chemistry are not just aesthetic choices,” said co-author Dr. Xiaowei Wu. “They can directly affect how much microplastic ends up in the ocean.”

The team suggests that textile manufacturers consider the light-absorbing properties of dyes when designing fabrics, as choosing colors and pigments with lower sunlight absorption could help slow down microfiber generation. Further studies will explore how additional factors such as biofouling, ocean currents, and fabric composition affect the environmental fate of microfibers.