Teabags use polypropylene, a plastic sealing, which when heated releases 11.6 billion microplastic particles into the water, a study from McGill University has found.
Natalie Tufenkji and colleagues from McGill University in Canada purchased four different commercial teas that are all packaged in plastic tea bags. They cut open the tea bag and removed the tea leaves and then heated the emptied tea bags into hot water to stimulate brewing the tea.
Using electron microscopy, the team found that a single plastic teabag at brewing temperature released about 11.6 billion micro-plastics and 3.1 billion nano-plastic particles into the water.
These levels are thousands of times higher than those reported previously in other studies, for example, a report in the Environmental Science and Technology Journal from June 2019, estimated that humans consume between 39,000 to 52,000 microplastic particles a year.
The health effects of ingesting these particles currently remain unknown, however, a study from Kings College London in 2017 hypothesised that cumulatively ingesting these plastic particles could be toxic.
Research led by Kieran Cox, a PhD candidate at the University of Victoria, looked at 26 papers all of which assessed the number of microplastics commonly consumed in food items. According to the study, there is no evidence to suggest they can penetrate the human body. However, once in the gut the microplastic particles may release harmful toxins or may enter the bloodstream.
According to the website Country Living, several UK tea brands use the plastic sealing on their tea bags, including PG Tips, Tetley and Yorkshire Tea.
Yorkshire Tea wrote in February 2019: ‘We want to be more environmentally friendly – including changing our tea bags so they’re sealed with a renewable, plant-based material.’
The company continued: ‘We’ve been doing a ton of work to get the new material working properly on our machines. Were still planning to have switched all UK tea bags to the new material by the end of the year.’
Microplastic pollution ‘number one threat to humankind’, claimed a report in February.
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