New study finds that microplastics can help dangerous bacteria survive on Scottish beaches
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New research from the University of Stirling has found that dangerous bacteria are able to survive the journey from sewage treatment plants to beaches on microplastic pollution.
During their study, scientists from the University’s Faculty of Natural Sciences found drug-resistant bacteria colonising microplastics on Scottish beaches.
The findings could have global consequences, with an estimated 2.3 million tonnes of plastic pollution thought to be floating in the world’s oceans.
Lead researcher Rebecca Metcalf, supervised by Professor Richard Quilliam, conducted her research by subjecting microplastics colonised by bacteria in wastewater to the different environments that they would likely pass through on their way to our beaches. She found that not only could the bacteria such a E. coli survive the entire journey, but that viable bacteria also survived for seven days on the sand.
Ms Metcalf said: “The plastic is providing a substrate for transferring pathogens from wastewater, and through river water, estuary and seawater and finally up onto the beaches where they are much more likely to come into contact with humans.
“Other surfaces where bacteria colonise, such as seaweed, wouldn’t necessarily go through that transfer route.”
We hope that our research will add to the growing overarching evidence and support for increasing public awareness and ultimately pushes towards legislative changes for plastic discharge to the environment.
Concerned by their findings, Ms Metcalf wanted to see if this theoretical survival was happening on real beaches in Scotland. The team collected polyethene and polystyrene plastic waste from 10 Scottish beaches and screened them for seven target bacteria that cause disease in humans. They found that these bacteria were present in virtually all of the samples, with some showing resistance to our most commonly used antibiotics.
This is worrying in light of sewage leaks and wastewater overflows onto our beaches. Ms Metcalf explained: “We already have sewage ending up in the environment that contains harmful bacteria. But the plastics are transporting bacteria into places where they are more likely to come into contact with people.
“We hope that our research will add to the growing overarching evidence and support for increasing public awareness and ultimately pushes towards legislative changes for plastic discharge to the environment.”
Further research is required to fully understand the potential risk that this may pose to those bathing at Britain’s beaches, as the likelihood for these pathogens to cause disease in humans is unknown.
Researchers still urge the public to take care around plastic pollution but stress the importance of removing plastic from our beaches. They say: “Don’t be afraid of taking part in a beach clean, it is vital that we remove the plastics from our beaches and dispose of them correctly, but I would encourage the public to wash their hands or use gloves.”
This work was supported by the UKRI Natural Environment Research Council (NERC) as part of the project, “Microbial hitchhikers of marine plastics: the survival, persistence & ecology of microbial communities in the ‘Plastisphere’”.