Research indicates that brightly colored plastics, such as red, blue, and green, decompose into microplastics more rapidly than lighter or colorless plastics, posing risks to both users and the environment.
Many retailers are being urged to cease the production of brightly colored plastic items, such as water bottles, outdoor furniture, and toys, after researchers discovered that these items break down into microplastics faster than lighter-colored plastics.
According to results from a research project conducted by the University of Leicester, plastics in red, blue, and green colors degrade into smaller pieces within three years, while samples of black, white, and silver plastics show less degradation.
Brightly colored plastics decompose faster than other colored plastics. (Photo: The Guardian).
With the current severe environmental pollution due to plastic waste, microplastics—tiny plastic particles—can be found almost everywhere. Recently, studies have discovered microplastics in human testicles, and scientists suggest that this may lead to decreased sperm counts in men.
Scientists in the United Kingdom and at the University of Cape Town in South Africa conducted several additional studies to demonstrate that plastic products with the same composition degrade at different rates depending on their color.
Researchers in the UK placed plastic lids of various colors on the roof of the university building for three years to expose them to sunlight. Meanwhile, the study in South Africa used plastic items collected from a remote beach.
Dr. Sarah Key, the project leader, stated: “It was surprising that the plastic samples placed on the roof of the University of Leicester and those collected from a windy beach at the southern tip of the African continent yielded similar results. Both experiments found that under well-ventilated environmental conditions over three years, plastics of different colors showed differences in degradation rates.”
This research has been published in an environmental pollution journal and provides the first evidence that brightly colored plastics decompose faster.
Therefore, retailers and plastic manufacturers need to be more mindful of the colors of plastic products during production.
Adam Herriott, a senior plastics expert at the anti-waste charity Warp, noted that while colored plastics are often used to make products stand out in stores, manufacturers should avoid using them to facilitate the recycling process.
“If different colored plastics are mixed during recycling, the resulting plastic product will be an unappealing gray or green”, Mr. Adam explained.
He added: “It would be much better if we could avoid using brightly colored plastics in food packaging, especially in items that are more likely to be discarded carelessly, like snack bags or bottle caps.”
The research results indicate that white, black, and silver colorants help protect plastics from the effects of ultraviolet radiation, while other colors do not. The detrimental effects of ultraviolet rays alter the internal polymer structure of plastics, making them brittle and more prone to breaking.
“Manufacturers should consider both the recyclability and the potential for plastics to be improperly disposed of when designing plastic products and packaging”, Dr. Sarah Key stated.
She further mentioned: “For outdoor items or those that are frequently exposed to sunlight, such as plastic furniture, it is advisable to avoid using red, blue, and green plastics to maximize their longevity.”
