New 'nanoplastics' could pose environmental risk, UCC scientists find

New 'nanoplastics' could pose environmental risk, UCC scientists find
Stock image: A Hawksbill turtle with a plastic bag.

UCC scientists have discovered that small crustaceans can break down microplastics into smaller 'nanoplastics' in just four days.

The new findings will have significant consequences on our understanding of microplastics and how they affect our environment.

The University College Cork researchers discovered that in our freshwaters, microplastics, which are plastic pieces smaller than 5 mm, are being broken down into even smaller nanoplastics that are at least five thousand times smaller in size (smaller than 1 µm).

The nanoplastics are being broken down by a very common Irish freshwater invertebrate animal, at a much faster speed than previously thought.

The alarming results of this EPA-funded study also reveal a potential new health hazard. While microplastics can become stuck in the gut of seabirds and fish, current understanding suggests that the smaller nanoplastic particles could penetrate cells and tissues, where their effects could be much harder to predict.

Top image the freshwater amphipods Gammarus duebeni and their plant food source Lemna minor. Bottom left image shows two fragmented microplastics in an amphipod’s gut. Bottom right image shows a nanoplastic fragment inside an amphipod’s gut. Photos credit: UCC Researcher Alicia Mateos-Cárdenas.
Top image the freshwater amphipods Gammarus duebeni and their plant food source Lemna minor. Bottom left image shows two fragmented microplastics in an amphipod’s gut. Bottom right image shows a nanoplastic fragment inside an amphipod’s gut. Photos credit: UCC Researcher Alicia Mateos-Cárdenas.

Until now, the breakdown of plastics was thought to occur mainly through sunlight or wave action — both very slow processes in the marine environment, and the breakdown took years or decades. 

"We have found that the freshwater amphipod, a small crustacean, called Gammarus duebeni is able to fragment microplastics into different shapes and sizes, including nanoplastics, in less than four days," said the study's leader, Dr Alicia Mateos-Cárdenas, of UCC's School of BEES and Environmental Research Institute.

"Whilst this species lives in Irish streams, they belong to a bigger animal group of invertebrates commonly found around the world in freshwaters and oceans.  

Our finding has substantial consequences for the understanding of the environmental fate of microplastics.

"These invertebrates are very important in ecosystems because they are prey for fish and birds, hence any nanoplastic fragments that they produce may be entering food chains. The data in this study will help us to understand the role of animals in determining the fate of plastics in our waters, but further research is urgently needed to uncover the full impact of these particles."

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