From kelp voyaging to Antarctica to monkeys rafting across the seas, Planet Earth is no stranger to living things journeying across its oceans. But it seems there are some more sinister seafarers out there; according to new research, harmful bacteria are hitchhiking on tiny bits of plastic, potentially contributing to the spread of disease.

A team of scientists from the University of Stirling investigated whether harmful pathogens could persist on ocean plastics. In particular, they examined nurdles (aka mermaid’s tears), tiny balls of plastic that serve as the basis for manufacturing plastic products. Billions of these 5-millimeter plastic pieces inhabit our oceans as a result of industrial spillages, and can be harmful to marine life. Their findings are reported in the Marine Pollution Bulletin.

The researchers examined nurdles on five Scottish beaches and discovered that 45 percent were contaminated with E. coli, while 90 percent carried Vibrio, a nasty type of bacteria that causes food poisoning and gastroenteritis. The presence of E. coli is often a sign of sewage pollution – a very undesirable addition to beaches where people bathe.

“Brightly colored nurdles are a magnet for children – and you wouldn’t want children putting these in their mouths,” principal investigator Dr Richard Quilliam told The Guardian.

While it’s still early days for the new research, this isn’t the first time that nurdles have been linked to hitchhiking pathogens. A 2016 study found evidence of Vibrio bacteria on microplastics floating in the North and Baltic Seas, meanwhile, disease-carrying plastics have also been spotted in rivers in the US.

“The danger is that pathogens could be transported over large distances and survive for much longer than normal,” Quilliam explained to The Guardian, adding that cholera could make its way from India to the US, for example.

“When a pathogen is bound to a piece of plastic it’s going to be protected, as it can hide from things that normally kill it, like UV light.” 

The team also note in their study that with the continuation climate change, the problem is only likely to get worse, particularly as warming waters “could increase the geographical range of new and emerging diseases into coastal and marine environments.” What’s more, an increase in extreme weather could lead to a rise in marine plastics being dumped on land.

The researchers hope that their findings will encourage authorities to implement appropriate beach regulations in areas where members of the public might come into contact with disease-contaminated plastic debris.