Microplastics can harbour viruses, come off during cooking

Researchers from The University of Queensland’s Australian Centre for Water and Environmental Biotechnology recently investigated if microplastics have the ability to harbour viruses — with worrying results.

As explained by study co-leader Dr Ji Lu, the study started when wastewater was being tested to detect COVID-19 cases in the community, which spurred the team’s investigation into what could mediate virus transmission in water environments. Their results were published in the journal Water Research.

“We often hear about the human and environmental harm caused by microplastics in water, but there is little known about whether the tiny microplastic particles can carry viruses,” said study co-leader Associate Professor Jianhua Guo.

“What we found is that viruses can hitchhike on microplastics and prolong their infectivity, which means there could be an increased risk of virus transmission throughout waterways and the environment.”

Lu said the team used the E. coli bacteriophage in the study, which is a virus that infects and replicates within the bacteria itself and is not harmful to humans.

“By testing polystyrene particles of varying sizes, we found that more than 98% of the virus we used was found on the microplastic, and over half of the viruses could still be detected 10 days later — much longer than if the virus particles were free-floating in the water,” he said. The team also tested how sun exposure and the size of microplastics helped prolong the virus’s survival and found the more environmental damage on the microplastic, the more likely it was to carry viruses.

So how concerned should we be? Lu noted that the required dosage to be infectious to humans varies between different types of viruses, but there could be instances where the dosage is enough on a microplastic to cause potential infection.

“Because microplastics can potentially accumulate deadly viruses and travel through waterways, it might be risky to eat seafoods harvested from areas where they are frequently contaminated by microplastics,” he said.

On the subject of food, scientists from The University of Newcastle and Flinders University recently measured how millions of microplastic particles potentially come off during cooking and in the wash as non-stick pots and pans gradually lose their coating.

Just one surface crack on a Teflon-coated pan can release about 9100 plastic particles, the researchers found — and at a micro scale, Raman imaging and an algorithm model identified the release of 2.3 million microplastics and nanoplastics from broken coating.

“The non-stick coating material Teflon is generally a family member of PFAS,” said Dr Cheng Fang from The University of Newcastle.

“Given the fact PFAS is a big concern, these Teflon microparticles in our food might be a health concern [and] so needs investigating because we don’t know much about these emerging contaminants.”

The researchers developed a molecular spectrum approach to directly visualise and identify the Teflon microplastics and nanoplastics, which are more difficult to monitor than other plastics. Flinders University researcher Professor Youhong Tang said the study, published in the journal Science of The Total Environment, highlights the need to gain insights into the threat of Teflon plastic debris during daily cooking.

“It gives us a strong warning that we must be careful about selecting and using cooking utensils to avoid food contamination,” Tang said.

Image credit: iStock.com/dottedhippo

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