Over 21 tons of plastic nanoparticles in the Wadden Sea, study shows

The Wadden Sea contains more than 21 tons of invisible plastic particles, researchers from Utrecht University concluded in a study published on Friday. This finding may explain why a large part of the plastic that disappears into the ocean every year can no longer be recovered by researchers. The study suggests the plastic breaks down into nanoplastics that are difficult to detect.

The amount of nanoplastic found was unexpectedly large, says lead researcher Dušan Materić of the Institute for Marine and Atmospheric Research Utrecht (IMAU). "Especially because apparently there is just as much nanoplastic as microplastic in the Wadden Sea, while we expected less. That is worrying." Nanoplastic is even smaller than microplastic. It is so small that it can enter the cells of an organism if it is swallowed, inhaled or lands on the skin.

It is not yet known what exactly happens when fish and other animals ingest the invisible plastic particles. "There is a chance that some types of plastic are more toxic than others. This is still being researched. Once we know more, we can also take more targeted measures against the most toxic plastics," explains Materić. There is also a chance that nanoplastics will eventually break down into even smaller particles, until only organic molecules remain. "That too is still under investigation."

The new technique used for the analysis was carried out by Materić and another Utrecht researcher, Rupert Holzinger, together with Helge Niemann of the Royal Netherlands Institute for Sea Research (NIOZ). Water from the Wadden Sea was filtered and the plastic particles found were examined. Most of the plastic found was polystyrene.

"That is a plastic that quickly falls apart and is used, for example, in polystyrene foam," says Materić. The researchers also found many PET nanoparticles. This is widely used in clothing and for plastic bottles.

The research into the Wadden Sea has been published in the scientific journal Science of The Total Environment. Meanwhile, the scientists are investigating spots in the Atlantic Ocean, the North Sea and the Mediterranean Sea. Materić adds, "Hopefully this will give us a quick idea of ​​how far nanoplastics are spreading in the world's seas."