Researchers at the University of Stirling in Scotland have emphasized that removing pathogens from a facility via waste disposal doesn’t eliminate the threat of infection entirely.

The research, published in the journal Environmental Pollution, found that viruses can survive and remain infectious by binding with plastics in water sources. The result is that even when pathogens are cleared from facilities via cleaning and flushing them into sewers, they remain hazardous.

In fact, rotavirus can survive and remain infectious for up to three days when binding with microplastics. The study also found that gastrointestinal viruses in sewage are able to bind to small bits of plastic waste and then enter waterways, including rivers and lakes.

Although pathogens and viruses with lipid coatings such as the flu virus died quickly when in the freshwater environment, those without lipid coatings, such as the norovirus, could survive.

“Even if a wastewater treatment plant is doing everything it can to clean sewage waste, the water discharged still has microplastics in it, which are then transported down the river, into the estuary, and end up on the beach,” said Richard Quilliam, a professor of environment and health at Stirling University and coauthor of the study. “We weren’t sure how well viruses could survive by ‘hitch-hiking’ on plastic in the environment, but they do survive, and they do remain infectious…It doesn’t take many virus particles to make you sick.”

Ultimately, the report concluded that companies and facilities can go some way to helping to prevent infectious viruses in the waterways by decreasing their use of plastics and following proper plastic disposal/recycling protocols.