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Plastic pollution is a bigger evil than previously imagined and can help keep viruses alive and infectious in freshwater for days, found a new study.
This is especially dangerous since sewage water brimming with disease-causing microorganisms has been found to have large volumes of microplastics despite being treated, the study published recently in the journal Environmental Pollution showed.This eventually finds its way into oceans, it added.
A layer of microbial cells or biofilm forms on the surface of microplastics soon after they are released into fresh water, the scientists observed during the study. This nutrient-rich coating becomes a hospitable surface for microorganisms that hop onto the floating microplastics.
Viruses on microplastics remained alive in water for three days or more, said Richard Quilliam, lead researcher on the project at Stirling University, to The Guardian. This, he added, was time enough for wastewater drained into rivers to reach beaches.
Viruses can also latch onto natural components but plastic pollution lasts much longer, Quilliam added.
“Viruses associated with biofilm-colonised pellets were more stable compared to those remaining in the water,” the authors wrote in the paper.
The result remained the same in every wastewater treatment scenario, according to the researchers.
“The natural composition of the lake water used in each treatment may have played a role in virus particle aggregation,” the authors noted in the paper.
A combination of factors such as high microplastic abundance in wastewater, intrinsic characteristics of plastics such as buoyancy and hydrophobicity and a high loading of human viral pathogens into wastewater treatment processing provides significant scope for viruses to become associated with the surfaces of microplastics, the report added.
The viruses were tested for three days but a longer study period will determine exactly how long the viruses survive on the plastic surface.