The research team, as part of the BlueAdapt project, followed microplastics from hospital sewage all the way through treatment works and out to sea. The results found that particles can act as a kind of raft for harmful microbes, shielding them from the environment and helping them to survive.
Treatment plants removed 93% of microplastics overall. But the microplastic still left in the wastewater and in instances of storm discharge (where raw sewage is discharged into the environment), norovirus and bacteria, including those carrying antimicrobial resistant genes were transported into the receiving water. Wet wipes were found to be particularly problematic, trapping more viruses and resistant bacteria than smooth plastic beads because of their fibrous structure.
Under normal conditions, the researchers say the levels detected are unlikely to cause infections on their own. The bigger concern is during heavy rainfall, when sewage systems overflow and release untreated wastewaster directly into waterways, a common occurrence in the UK. During these events, microplastics carried high levels of virus and may transport pathogens into bathing waters and shellfish beds.
The study also found that the bacteria on microplastics changed significantly during treatment, by the time particles reached the final effluent, they were largely carrying bacteria from the treatment plant itself, many of which had resistance to antibiotics. This raises concerns about treatment works acting as a source of resistant microbes in the wider environment.
The researchers say better management of sewer overflows is a priority, and highlight wet wipes, the majority of which still contain plastic as a key source of the problem.
Lead researcher, Dr Jessica Kevill, Postdoctoral Research Officer at School of Environmental and Natural Sciences said: “By showing that microplastics can carry pathogens and resistance genes through treatment and into receiving waters, this study underscores the urgent need to address wastewater management practices and improve water quality in the UK.”
Funded by Horizon Europe and UKRI, this research contributes to a growing body of work examining how environmental change and pollution affects our health, water quality and coastal ecosystems. BlueAdapt is helping to generate the evidence needed to inform policy, support more resilient wastewater systems, and protect coastal communities now and in the future. Find out more: blueadapt.eu
BlueAdapt is a pan-European research project that are investigating the impacts of climate change on risks to human health posed by pathogens and antimicrobial drug resistant bacteria in coastal waters.
On Wednesday, 24 June Dr Kevill will speak at BlueAdapt’s upcoming workshop to inspire innovation to protect people from the health risks of pollution in coastal waters. Organised by BlueAdapt’s partner, the University of Exeter, you can register for the event here: www.blueadapt.eu/online-workshop/
