A recent study conducted by researchers from the University of Leicester in the United Kingdom and the University of Cape Town in South Africa revealed that brightly colored plastics, such as red, blue, and green, degrade into harmful microplastics more rapidly than black, white, and silver counterparts.
TOPSHOT - A photo taken on December 8, 2022, in Vaasa, shows plastic pieces in frozen water.Photo by OLIVIER MORIN/AFP via Getty Images
Brightly Colored Plastics Lead to More Microplastics
The study found that plastics with bright colors degrade more quickly into microplastics compared to plain-colored plastics.
Microplastics, or tiny plastic particles, present serious environmental and health risks since they can emit toxic additives and be consumed by wildlife and humans via the food chain and water sources.
The research involved two complementary studies conducted over three years. In the UK, researchers placed bottle lids of various colors on the roof of a university building in Leicester to expose them to the sun and elements. In South Africa, the team collected differently colored plastic items from a remote beach, analyzing items based on their manufacturing date stamps.
The research was led by Dr. Sarah Key during her PhD at the University of Leicester's School of Chemistry. Co-author Professor Sarah Gabbott from the University of Leicester's School of Geography, Geology, and the Environment also played a key role in the study.
How Plastic Color Matters
This study, published in the journal Environmental Pollution, is the first to provide field evidence that the colorant in plastic products significantly affects the rate of degradation and microplastic formation. These findings have important implications for manufacturers and retailers in designing more sustainable plastic products.
The researchers used advanced techniques to measure the chemical degradation and structural integrity of the plastics. Fourier-transform infrared spectroscopy (FTIR) was employed to assess how much the samples had reacted with oxygen in the air, while a breaking strength test measured how brittle and prone to fragmentation the plastics had become.
The results showed a stark contrast between the degradation rates of brightly colored-and plain-colored plastics. Dr. Key noted in a statement, "It's amazing that samples left to weather on a rooftop in Leicester in the UK and those collected on a windswept beach at the southern tip of the African continent show similar results."
Brightly colored plastics like red and green became very brittle and fragmented quickly, while black, white, and silver plastics remained largely intact.
The study also found that black, white, and silver colorants protect the plastic from damaging ultraviolet (UV) radiation, which otherwise makes plastics brittle and prone to breaking down.
Professor Gabbott explained that the study revealed a higher likelihood of brightly colored microplastics in the environment, as red, green, and blue plastics are more prone to fragmenting into millions of tiny, colorful particles.
These findings suggest that retailers and manufacturers should reconsider the use of bright pigments in plastic products, especially those designed for outdoor use.
Dr. Key emphasized that manufacturers should take into account the recyclability of the material and the likelihood of it being littered when designing plastic items and packaging.
She advised avoiding bright colors for items extensively exposed to sunlight, such as outdoor furniture, to enhance durability and reduce microplastic pollution.
