Microplastics in water can carry viruses, but should we worry?

Researchers investigated the stability of viruses over time when suspended in water containing microplastics.
They found that viruses can attach to microplastics and remain more stable than in water alone.
They note that further research is needed to understand how long pathogens can survive by binding to microplastics.
Microplastics are plastic particles that are under 5 millimeters (mm) in size. Once in the environment, they are quickly colonized by microorganisms. Previous researchTrusted Source suggests that human and animal pathogens may be able to “hitchhike” on microplastics and thus spread to different areas.
Although wastewater treatment plants remove up to 99% of microplastics from sewage water, sewage water remains one of the main sources by which microplastics enter the environment.
This presents a risk for pathogens from human waste to attach to bacterial colonies known as biofilms on plastics. Knowing whether or not pathogens that sit in microplastic biofilms remain infectious could aid public health initiatives.
Recently, researchers assessed the stability of viruses when submerged in water containing microplastics. They found that viruses attached to microplastic biofilms were more stable than when in water alone.
The study appears in Environmental Pollution.
For the study, the researchers tested two types of viruses. One, a bacteriophage — bacteria-eating virus — known as Phi6, had an “envelope” or lipid coat around it similar to the flu virus, while the other — rotavirus strain SA11 (RV)— was “non-enveloped.”
To begin, the researchers grew biofilms on 2 mm polyethylene microplastic pellets by inserting them into flasks containing filtered lake water, unfiltered lake water, or water infused with nutrients to encourage microbial growth for 7–14 days.
Biofilms formed on all three water treatments, although they formed more rapidly among the pellets from the nutrient-based water source.
The biofilm-coated pellets were then inserted in flasks containing 100 milliliters (ml) of fresh lake water and 1 ml of either Phi6 or rotavirus SA11 at concentrations typical to wastewater samples.