Scientists warn that your morning cup of coffee or tea is likely full of invisible microplastics

A new study tested everyday drinks and found that hot tea and hot coffee contained the highest concentrations of invisible microplastics.

Microplastics have now been found in just about every place that scientists search for them. They have been detected in human blood and in human brains, and even in human testicles.

The team sampled 155 beverages across 31 drink types from UK shops and cafes, then counted synthetic plastic particles larger than 10 micrometers using micro FT-IR imaging.

The highest averages showed up in hot tea and hot coffee, while iced versions of the same drinks contained fewer particles.

The study team included Mohamed Abou-Elwafa Abdallah, of University of Birmingham. The work focused on synthetics rather than natural fibers, and it cataloged the polymer types most often found.

Understanding microplastics – the basics

Microplastics are tiny plastic pieces that are less than five millimeters in size, about as small as a sesame seed or even smaller.

They form when larger plastic items, like bottles or bags, break down into smaller fragments through sunlight, waves, or wear and tear.

Some microplastics are made intentionally, such as the microbeads once used in face washes and toothpaste.

Because plastics don’t biodegrade easily, these fragments linger in the environment for decades or even centuries, moving through soil, rivers, and oceans.

Scientists are still studying how microplastics affect health, but they already know that these particles can carry toxic chemicals and disrupt organisms at the cellular level.

Coffee, tea, and microplastics

Across the product range, average concentrations per liter landed in clear bands.

Hot tea measured about 60 particles per liter, hot coffee about 43 microplastic particles per liter, with iced tea around 31 and iced coffee around 37.

Juices and energy drinks sat lower on the list, and soft drinks were lowest among the tested categories.

Fragments dominated over fibers in shape, which aligns with wear and shedding from packaging and equipment during processing.

“High temperatures enhanced microplastics release from packaging to beverages,” noted Al-Mansoori.

Container choice also matters. Disposable, plastic-lined paper cups and plastic caps contribute particles, and the polymer fingerprint in many drinks tracked the packaging in contact with the liquid.

The four names that came up most were polypropylene, polystyrene, polyethylene terephthalate, and polyethylene. Each appears widely in food contact items, from cup linings and lids to bottles and seals.

Particle sizes fell mostly between 10 and 157 micrometers. That upper bound reflects the detection limits of the method, so the true picture likely includes smaller fragments and possibly nanoplastics that this technique does not capture.

Microplastics beyond coffee

Scientists have quantified polymer particles in circulating blood, establishing internal exposure in healthy volunteers.

The first measurement of mass concentration in blood landed near 1.6 micrograms per milliliter for composite polymer content.

Recent human autopsy research reported higher concentrations of particles in brain tissue than in the liver or kidneys, with evidence that levels in 2024 samples were roughly half again higher than in 2016 samples.

Separate work identified plastic particles in all examined human testicles, raising urgent questions that only follow up studies can answer.

How this rethinks exposure

Previous attention focused on water. An earlier UK analysis reported that average concentrations in tap water and bottled water were statistically close, which already pushed the conversation beyond a single source.

This new beverage-wide look shows that counting only water underestimates daily intake. Hot drinks can add substantially to exposure because they interact with plastic surfaces at higher temperatures.

The highest counts were measured in hot tea served in disposable cups. Tea brewed in glassware showed fewer particles on average, which points toward the route by which plastics are making contact with the beverage.

For coffee, the pattern tracked with cup linings and lids, as well as with the components inside brewing systems. Iced versions often contained fewer particles, though packaging material and handling still mattered.

What this means for health research

Toxicology findings on particle size and shape suggest that smaller fragments may move more easily through tissues.

That is one reason method limits are so important to interpreting risk, since many tools cannot quantify the smallest sizes.

Human data remain early, but the presence of synthetic particles in major organs and fluids shifts the burden of proof.

Scientists now need exposure standards, sensitive methods, and longitudinal studies that track outcomes over time.

Safeguarding our coffee from microplastics

“We found a ubiquitous presence of microplastics in all the cold and hot drinks we looked at,” said Abdallah.

Packaging standards, manufacturing controls, and better labeling can help. Comparable sampling frameworks across countries would also clarify which interventions cut exposures most effectively.

Analytical tools that can enumerate particles below 10 micrometers will close key gaps.

Studies that connect polymer type, temperature, contact time, and agitation to particle release will also refine source attribution.

Exposure modeling needs to incorporate total daily beverage intake rather than water alone. That approach will make risk estimates more realistic for how people actually drink through a day.

The study is published in Science of The Total Environment.

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