Hot drink lovers might want to think again before grabbing a cup of coffee or tea on-the-go, as disposable plastic cups have been found to release thousands of microplastics into drinks, a new study has warned.
Microplastics can be formed from the breakdown of larger plastic items or be released directly from products during their use.
“These particles end up in our environment, our food, and eventually, our bodies,” said paper author and environmental scientist Xiangyu Liu of Griffith University, Australia, in a statement.
In their study, Liu and colleagues reviewed data from 30 peer-reviewed studies, looked at how common plastics such as polyethylene and polypropylene behave in different conditions.
The study found that “heat is a primary driver of microplastic release, and the material of your cup matters more than you might think,” Liu wrote in an article for The Conversation.
“If that cup is made of plastic, or has a thin plastic lining, there is a high chance it’s shedding thousands of tiny plastic fragments directly into your drink.”
Microplastics are plastic particles that range in size from around 1 micrometer to 5 millimeters, “roughly from a speck of dust to the size of a sesame seed,” Liu explains.
In their study, the team found that microplastic release from products made of polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS) “significantly increased with temperature.”
The reported releases of microplastics ranged from a few hundred particles to over 8 million particles per liter, depending on the material and study design. Paper cups with plastic linings were found to release fewer microplastics than all-plastic cups.
The researchers explained that “PE-coated paper cups consistently released fewer MPs than PE plastic cups at both 5°C and 60°C. Specifically, MP release from PE cups increased by 32.7 percent when the temperature rose from 5°C to 60°C, a trend not observed in the PE-coated paper cups.”
However, “soaking time,” meaning how long the drink sits in the cup, was not found to be a consistent driver of microplastic release. Liu said: “This suggests that leaving our drink in a plastic cup for a long time isn’t as important as the initial temperature of the liquid when it first hits the plastic.”
The latest research comes as 500 billion single-use cups are reported to be used each year, according to a 2021 report published by the United Nations Environment Programme (UNEP).
“The use of disposable beverage cups is set to rise exponentially,” the report cautioned. “Urgent action is therefore needed…to find sustainable alternatives for consuming beverages outside of the home.”
UNEP explains that “microplastics can enter the human body through ingestion and inhalation” and they have been “found throughout the human body, including in the walls of arteries.”
According to a 2019 study, UNEP added, “some adults could potentially be consuming between 39,000 to 52,000 microplastics particles a year on average, depending on their location and what they do.”
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References
Liu, X., Li, D., Li, Z., Ball, A. S., & Chen, C. (2026). Release of microplastics from commonly used plastic containers: Combined meta-analysis and case study. Journal of Hazardous Materials: Plastics, 2. https://doi.org/10.1016/j.hazmp.2025.100028
Marfella, R., Prattichizzo, F., Sardu, C., Fulgenzi, G., Graciotti, L., Spadoni, T., D’Onofrio, N., Scisciola, L., Grotta, R. L., Frigé, C., Pellegrini, V., Municinò, M., Siniscalchi, M., Spinetti, F., Vigliotti, G., Vecchione, C., Carrizzo, A., Accarino, G., Squillante, A., … Paolisso, G. (2024). Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. New England Journal of Medicine, 390(10), 900–910. https://doi.org/10.1056/NEJMoa2309822
United Nations Environment Programme. (2021). Single-use beverage cups and their alternatives: Recommendations from life cycle assessments. United Nations Environment Programme.
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