Scottish beaches exposed to microplastics may offer a habitat for hazardous bacteria to thrive.

It has been understood for some time that microplastics provide a protective environment (the so-called “plastic ball”) in which bacteria can live in wastewater. For the first time, researchers at the University of Stirling, Scotland, have tracked how this might enable bacteria to survive the journey out to sea and make their way to our shores, where they can come into contact with humans.

Lead researcher Rebecca Metcalfe, under the direction of Professor Richard Quilliam, exposed microplastic particles that bacteria have colonized in wastewater to the different environments they are likely to pass through on their way to our shores. Metcalfe and her team found that not only could bacteria such as Escherichia coli survive the entire trip, but also viable bacteria survived for 7 days on the sand.

“Plastic provides a substrate for the transfer of pathogens from wastewater, through river and estuary waters, seawater, and finally to beaches where they are most likely to come into contact with humans,” explains Metcalf. “Other surfaces where bacteria settle, such as seaweed, will not necessarily pass through this route of transmission.”

Concerned by their findings, Metcalfe wanted to know if this theoretical survival was occurring on the real beaches in Scotland. They collected polyethylene and polystyrene plastic waste from 10 Scottish beaches and screened it for seven target bacteria that cause disease in humans. Alarmingly, they found that these bacteria were present in almost all samples, with some showing resistance to our most commonly used antibiotics.

This is worrisome in light of sewage intrusion and sewage flows onto our beaches. “We already have wastewater that ends up in the environment that contains harmful bacteria,” Metcalf says. “But plastic carries bacteria to places where they are more likely to come into contact with people.”

“We hope our research will add to the growing comprehensive evidence and support increased public awareness and ultimately drive toward legislative changes for the disposal of plastics in the environment.”

Research still needs to be done to fully understand the potential risk this may pose to those bathing on Britain’s beaches, as the potential for these pathogens to infect humans is unknown. Still, the researchers urge the public to be concerned about plastic pollution, but stress the importance of removing plastic from our beaches.

“Don’t be afraid to participate in a beach cleanup, it is essential to remove plastics from our beaches and dispose of them properly, but I would encourage the public to wash their hands or use gloves.”