A new study of 155 drink samples sold in the UK found that all of them contained microplastics, while hot drinks such as coffee and tea contained elevated amounts.
The study suggests that hotter temperatures combined with plastic-lined to-go cups may result in the highest amount of microplastics entering the human body, based on a comparison of common drink types.
Led by a team at the University of Birmingham (UK) and slated for publication in the Sept. 20 issue of Science of the Total Environment, the study combined lab testing of plastics in drinks with consumer surveys to estimate how much microplastic content people may actually take in from beverages they consume each day.
Microplastics — tiny plastic particles that are now widespread pollutants in our water, air and food — continue to be an intense subject of academic research due to their potential long-term effects on human health. Previous research has linked microplastic chemical toxicity to health issues such as inflammation, DNA damage, reproductive problems and even cancer.
“Although few studies have assessed human exposure to microplastics (MPs) via drinking, almost all have considered human daily fluid intake as composed solely of water,” the study authors wrote. “This study aims to comprehensively assess human exposure to MPs via total fluid intake, including beverages (hot and/or cold), as well as water (tap and/or bottled).”
Methods and Drink Types
Researchers bought common drinks from major UK retailers and coffee chains between August and December 2024. They analyzed 31 products with five separate samples each, for a total of 155 measurements.
Coffee categories included: hot to-go cups from four chains; instant coffee “sachets” prepared in glass cups; coffee capsules brewed on three machines and poured into glass; and iced coffee from two shop brands. Other categories included hot tea, iced tea, fruit juice, energy drinks and soft drinks.
Each beverage was filtered, and the trapped particles were identified by micro-FTIR, a microscopy technique that reads a particle’s infrared “fingerprint” to tell what plastic it is.
Packaging and Temperature
Across all drinks, the plastics most often identified were polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET) and polyethylene (PE). The patterns point to packaging as a key source.
Hot beverages generally had higher counts of microplastics than cold ones, consistent with heat helping tiny pieces break off or migrate from plastic packaging into the drink. For coffee, fragment-type particles dominated, and hot to-go formats tended to show higher levels than iced coffee or coffee served in glassware.
On average, hot coffee contained about 43 particles of microplastics per liter, while iced coffee contained approximately 37 particles per liter. Hot tea was found to have the highest concentration of microplastics per liter, at about 60.
Among other popular drinks, fruit juices contained an average of 30 microplastic particles per liter, energy drinks averaged 25 and soft drinks had the lowest concentration at an average of 17.
When analyzing the results, the research team suggests that microplastic intake from beverages may be historically undercounted in previous studies, which have focused largely on water alone.
“This serves as a critical step towards better understanding of the extent of MPs exposure under real-life scenarios and advocates for more comprehensive studies for accurate risk assessment of MPs intake via dietary sources to enable broader environmental and public health interventions,” they wrote.
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