Biofilms on Plastic Deposited in Beach Sand Contain Pathogenic and Antibiotic-Resistant Bacteria, According to New Study: Biofilms on Polystyrene and Nurdles and the Escape of Bio-beads Used in Wastewater Treatment Are Most Concerning

     Scientists are warning in a new study that the more than 125 trillion microplastic particles now circulating in the world’s oceans are carrying dangerous bacteria. Some carry antimicrobial-resistant microbes, which has prompted warnings to use gloves while handling beach debris, including sand. According to Amaze Lab, the U.K. study provides:

“…a unique insight into microplastic-mediated pathogen transport, setting the stage for understanding both human and environmental consequences.”

     The study suggests that beach cleanup volunteers are at significant risk. Coastal populations, shellfish workers, and wastewater employees are also at risk. Volunteers are advised to wear impermeable gloves like nitrile gloves and to wash their hands thoroughly after a cleanup.

“Microplastics form dense biofilms, creating a “Plastisphere” ecosystem. The University of Exeter press release notes, “These communities may often include pathogenic or antimicrobial resistant bacteria.” Polystyrene and nurdles are particularly hazardous, as they adsorb antibiotics from wastewater and facilitate gene exchange between bacteria.”

“This combination of adsorption, biofilm stability, and horizontal gene transfer renders microplastics into pathways for pathogens.”

“Polystyrene and nurdles pose a greater risk of antimicrobial resistance than glass or wood. The November 19, 2025, study notes that their surfaces “promote biofilm formation that facilitates transfer of antimicrobial resistance genes.” These microplastics effectively become vehicles, transporting pathogens across rivers, estuaries, and oceans.”

     The nurdles, which are polyethylene pellets that routinely escape from plastics plants, also break down, as do bio-beads, shedding microplastic particles.

 

Biofilms and Bio-Beads

     The study also noted that biofilms on microplastics serve to transport pathogens, which contradicts the idea that they are being diluted. They survive intact within the biofilms after transport. Of particular concern is that they can transport pathogens from sewage works intact to beaches and swimming areas. One very direct source of concern that has been identified is the use of bio-beads at wastewater treatment plants. A recent spill of 10 tons of bio-beads escaped from a treatment facility via a 21-mile pipe to Camber Sands, East Sussex. The company, Southern Water, blamed the release on equipment failure. However, biobeads have also been found deposited in another area of the U.K., suggesting releases from other wastewater treatment facilities, which is currently being investigated. Companies are required to report any such releases.

“Biobeads are used in wastewater treatment facilities to provide surface area for bacterial attachment. The outlet noted that a nearby United Utilities wastewater treatment plant uses the beads in its processes before discharging treated water into the river.”

     Amaze Lab notes that the concept of biofilms as a "plastisphere" is still new, but is being explored. It is also noted that the prevalence of antimicrobial-resistant (AMR) bacteria may be associated with wastewater from hospitals, where such bacteria are common.  

“The “Plastisphere” concept emerged in 2019–2021, identifying biofilm communities distinct from natural substrates. By 2024, bio-bead pollution prompted regulatory attention, and coastal tourism studies emphasized economic vulnerability.”

“The 2025 study links hospital wastewater to marine microplastics, quantifying the prevalence of antimicrobial resistance genes. Understanding this history frames the urgency for mitigation strategies.”

     Dr. Aimee Murray stated:

“Our research shows that microplastics aren't just an environmental issue – they may also play a role in the dissemination of antimicrobial resistance.”

“The study team, led by Dr Emily Stevenson and involving scientists from Plymouth Marine Laboratory and the University of Exeter, developed a novel structure that would allow five different substrates (bio-beads, nurdles, polystyrene, wood and glass) to be secured along a waterway that was expected to decrease in anthropogenic pollution downstream.”

     The biofilms on each substrate were examined after two months. Then they were analyzed with metagenomics: “the genomic analysis of genetic material collected from an entire community of organisms in a specific environment.”

Possible Solutions

     Aging infrastructure, limitations of screen mesh, and improper storage have been implicated in bio-bead spills from wastewater treatment plants.

“Southern Water and other utilities must improve their infrastructure by implementing battery-powered sieves, Nurdle machines, enhanced mesh screens, and secondary containment. Proactive upgrades reduce environmental release and AMR propagation.”

“Investment is costly upfront, but cheaper than remediation. Long-term benefits include cleaner waterways, safer beaches, and reduced risk of superbug spread.”

     Protection of aquaculture facilities by filtering intake water and siting facilities away from wastewater discharge zones is also recommended. Plastics manufacturers must also increase their filtration effectiveness to avoid releases of nurdles, which are common near facilities that produce them. Bio-beads are also hazardous to wildlife as they can be mistaken for food.

     Two authors of the paper also authored an article published in The Conversation, where they noted that, unlike the nurdles that they resemble, bio-beads are compressed, like a concertina, to maximize their surface area-to-volume ratio. This provides more surface area for bacterial growth, which is the goal during aerobic sewage and wastewater treatment.

     They also suggest in the article that the risk of bio-bead spills can be reduced by updating aging infrastructure, improving filtration, and redesigning substrates that assist decomposition and treatment by microbes.

“Alternative wastewater treatment methods exist. Not all wastewater treatment works use bio-beads, proving they’re not essential. Some facilities use different plastic designs (large flat surfaces rather than floating pellets) or denser materials such as ceramic or stone that are less likely to escape.”

     They note that one way to quantify bio-bead losses is to require the water companies to disclose how much they buy, presumably to replace what was lost.

“This issue demands transparency and accountability. If water companies disclose how many bio-beads they use and how frequently they require replacement, the scale of losses could be quantified. It’s equally important that spillages are reported and pressure for more environmentally sustainable methods is sustained.”

     In the future, they plan to compare different plastic polymers for biofilm development.

 

      

 

 

References:

 

67M Americans Told ‘Wear Gloves On Beaches’ After Microplastics Linked To Superbugs. Rodrik Cassel. Amaze Lab. December 1, 2025. 67M Americans Told ‘Wear Gloves On Beaches’ After Microplastics Linked To Superbugs

Officials launch investigation after mysterious beads wash up on river banks: 'There must have been millions of them'. Kim LaCapria. The Cool Down, December 17, 2025. Officials launch investigation after mysterious beads wash up on river banks: 'There must have been millions of them'

Sewers to Seas: exploring pathogens and antimicrobial resistance on microplastics from hospital wastewater to marine environments

Emily M Stevenson, Angus Buckling, Matthew Cole, April Hayes, Penelope K. Lindeque, and Aimee K. Murray. Environment International. Volume 206, December 2025, 109944. Sewers to Seas: exploring pathogens and antimicrobial resistance on microplastics from hospital wastewater to marine environments - ScienceDirect

Microplastics pose a human health risk in more ways than one. Alex Morrison. University of Exeter News. November 2025. Microplastics pose a human health risk in more ways than one - University of Exeter News

Plastic ‘bio-beads’ from sewage plants are polluting the oceans and spreading superbugs – but there are alternatives. Pennie Lindeque and Emily Stevenson. The Conversation. November 24, 2025. Plastic ‘bio-beads’ from sewage plants are polluting the oceans and spreading superbugs – but there are alternatives