You know that black t-shirt that you love to wear in the summer because it “goes with everything”? Well, under the sun and in water, that same shirt could turn into a tiny generator of microplastics.
According to a new study conducted by the Chinese Research Academy of Environmental Sciences and Nanjing University of Information Science and Technology, darker synthetic fabrics degrade faster in sunlight, releasing huge amounts of microfibers into the marine environment.
How the sun turns clothes into invisible pollution
The researchers tested different types of colored polyester in simulated seawater. After just 12 days of exposure to light, the equivalent of about a year of sunshine in coastal waters, the fibers were already starting to crumble. And the numbers are impressive: from just 0.1 grams of purple fabric, almost 47,400 microfibers broke off.
The green fabrics lost 37,020, the yellow ones 23,250, and the blue ones “only” 14,400. Each fiber is thinner than a human hair, but once in the sea it can be ingested by fish, plankton and molluscs, entering the food chain — and, inevitably, onto our plates.
Dr. Xiaoli Zhao, lead author of the study, explained:
Sunlight acts like a slow but relentless pair of scissors.
Ultraviolet radiation breaks the chemical bonds of plastic polymers and activates the formation of reactive oxygen species (ROS), molecules that “corrode” the fibers from the inside, making them brittle and prone to breaking.
Why do dark colors pollute more?
Darker fibers — like purple or green — absorb more solar energy, speeding up degradation. The dyes used (often nitro and azo) amplify the problem, trapping UV rays and promoting the production of free radicals. In contrast, lighter colors such as yellow or blue reflect some of the light and deteriorate more slowly.
The research also highlights another interesting detail: the structure of the fabric matters. Dense fibers resist longer, while light or loosely woven fabrics fall apart sooner. In short, the fashion and chemistry of materials directly influence sea pollution.
And it doesn’t end here. Microfibres not only accumulate in the water, but absorb pesticides, heavy metals and other toxic substances, becoming vehicles of contamination for the entire marine ecosystem. Once ingested by organisms, they can cause inflammation, hormonal imbalances and a weakened immune system. It’s an invisible but constant domino effect.
What can we do
As researcher Xiaowei Wu, co-author of the study, recalls:
Fabric colors and dyes are not just an aesthetic issue: they have a direct impact on the environment.
For this reason, the solution could start from textile companies: choose dyes that are less reactive to light and design fibers that better resist sun exposure. And for us consumers? Small but concrete gestures: prefer natural fabrics, avoid washing synthetic items too often and above all choose light colours, which release fewer microfibres.
Because yes, even our wardrobe can contribute – for better or worse – to the health of the sea. Every dress that fades in the sun releases a tiny piece of itself into the water, a fragment that ends up in the bodies of the fish, in the seabed and, finally, in us. You don’t need to be a scientist to understand that the blue of the sea also depends on the color of our clothes.
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