There is almost no corner of our planet where they are not present: microplastics They are everywhere.
They have been found buried in the Antarctic ice, in the entrails of marine animals that inhabit the deepest ocean trenches, and in the drinking water consumed around the world.
They were also recently found in the testicles of humans.
But when it comes to fragmenting into these tiny pieces that measure between one and five millimeters, the brightly colored plastics do so at a much faster rate than the rest, according to a study led by researchers at the University of Leicester, in the United Kingdom.
The ones that are colored red, green and blue They degrade more quickly compared to those that are black, white or silver.
“Plastic is not just the polymer, but it has many different components. And the dye is, in fact, a significant part of its mass,” Andrew Abbott, professor of physical chemistry at the University of Leicester and co-author of the research, explains to BBC Mundo.
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And it is precisely these colorants that can protect the plastic or not (depending on the color in question) from harmful ultraviolet radiation which promotes its disintegration.
That is, all plastics degrade, but the rate at which they do so “will depend on the ability of the additive to protect them from oxidation,” adds Abbott.
Protection against ultraviolet rays
Researchers from the University of Leicester and the University of Cape Town in South Africa carried out two complementary studies to demonstrate the importance of color in plastics.
In one, they left bottle caps of different colors out in the open for three years.
“We found that the black, white and silver caps were – even after three years – almost exactly the same as when they left the factory.”
“The green, red and blue ones were quite broken, even under static conditions”dice Abbott.
The other study focused on plastics found on a remote beach, and yielded similar results.
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Rethink the design
Ultimately, it is not about favoring one color or another, but about designing the plastic objects and the color that will be given to them depending on the durability for which they are designed, point out the authors of the study.
Manufacturers, they say, must consider both the recyclability of the material and the likelihood of it becoming trash when designing plastic objects and packaging.
“For the objects used outdoors or that are heavily exposed to sunlight, such as plastic outdoor furniture, consideration should be given to avoid colors like red, green and blue,to make them last as long as possible,” explains Sarah Key, a researcher who led the project at the University of Leicester.
The same in the case of door and window frames, pipes or gutters,which are more durable when white, black or silver.
Instead, “when plastic is designed to break down, for example through the use of pro-oxidant additives, (manufacturers) should consider the role that color could play in this,” adds Key.
For short-lived plastics such as wrappers, bottle caps, etc., the study notes, “black should be avoided.” That is, the colors that make these objects more durable.
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The big problem with microplastics is that since they are present in almost all ecosystems on the planet, they end up being part of the food chain.
And although the health impact of ingesting microplastics is not yet fully understood, some research indicates it may negatively affect our endocrine system and the hormones that regulate our growth and development.
Its intake has also been linked to other health problems including cancer and coronary heart disease.