New evidence deepening the notoriety of microplastics as a pollutant and potential threat to human health has come with three separate studies showing how pervasive they have become.
Scientists at Trinity College Dublin have discovered the tiny particles are present in glitter products and damaging marine ecosystems.
UK researchers have meanwhile found them in the male reproductive system of sea turtles, which may increase the creatures’ risk of extinction, while a study in the United States has found significant quantities in chewing gum.
Microscopic bits of plastic have been found everywhere in the human body, as well as the remotest ecosystems and deepest oceans. The sources are well known and include plastic water bottles, microwaveable plastic containers and synthetic fibres – which release minute shreds that can be inhaled or ingested – made from PET (polyethylene terephthalate), one of the most common plastics used in manufacturing.
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A team at TCD’s School of Natural Sciences found PET-based glitter microplastics can actively influence biomineralisation processes in marine environments, raising fresh concerns about the long-term environmental impact of microplastic pollution.
Their research, published in Environmental Sciences Europe on Tuesday, shows these microplastics promote crystallisation of calcium carbonate (CaCO3) minerals, potentially affecting the natural growth and stability of marine calcifying sea organisms including those with shells and skeletons.
The study, which investigated six different types of PET glitter, found glitter microplastics provide sites for CaCO3 crystallisation, accelerating mineral formation and potentially altering skeletal structures in marine organisms.
This “surface crystallisation” on glitter can occur within hours or even minutes. The rapid process may also accelerate microplastic degradation, increasing release of harmful particles into marine environments.
Glitter is widely used in cosmetics, arts and crafts, fashion, and holiday decorations to add sparkle and shine. It is also used in industrial applications, such as automotive paints, textiles and anti-counterfeiting materials.
Its versatility means it is widely used, but its small size and plastic composition raise environmental concerns as most glitter waste eventually makes its way into seawater due to its small size and lightweight nature which make it difficult to capture in waste management systems.
“Our findings suggest PET glitter can serve as artificial templates for calcium carbonate formation, which may have unintended consequences for marine life,” said lead author Kristina Petra Zubovic. “This process could influence the structural integrity of marine organisms that rely on stable conditions for biomineralisation.”
Scientists at the University of Manchester have raised concerns about levels in the reproductive system of male sea turtles. They also found significant levels of microplastics in other organs of both male and female turtles.
They studied the bodies of 10 stranded loggerhead sea turtles, recovered by the Oceanogràfic Foundation of Valencia, that suffered drowning and exhaustion when they were accidentally caught up in commercial fishing nets.
The findings, published in Marine Environmental Research, could spell disaster for the majestic creatures already found in declining numbers in the world’s oceans.
It is the first study to show microplastics from the gut can translocate in sea turtles, opening up the possibility of different organs, especially the reproductive system, being directly affected.
The scientists believe microplastics may lead to systemic inflammation in the animals.
Meanwhile researchers at the University of California, Los Angeles, found synthetic chewing gums and natural chewing gums both shed microplastics into the saliva, which are then swallowed. With each piece of gum releasing up to 637 microplastic particles, it is not yet known if they cause humans any harm.
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Prof Oliver Jones, a chemist in Australia’s RMIT University said that if the relatively small number of microplastics were swallowed, they “would likely pass straight through you with no impact”.
“An interesting finding from this [small] study is that they found very similar levels of microplastics in both the synthetic and the natural gums, even though there weren’t supposed to be plastics in the natural gums at all,” he said.
“While microplastics are something we should definitely be keeping an eye on, I don’t think you have to stop chewing gum just yet – although you should certainly dispose of it appropriately in a bin when you are finished with it.”
