What are microplastics in drinking water?

Microplastics are plastic particles smaller than 5mm that contaminate drinking water. A 2023 study by Stanford Medicine found microplastics in the heart tissue of 60% of cardiac surgery patients. These particles come from plastic bottles, packaging, synthetic clothing fibers, and degraded plastic waste. They enter tap water through treatment plant filtration gaps and pipe degradation.

How do microplastics get into tap water?

Microplastics enter tap water through three main routes: (1) Water treatment plants can't filter particles smaller than 1 micron, allowing microplastics through, (2) Plastic water pipes degrade over time, shedding particles into the water supply, and (3) Environmental contamination from plastic waste in rivers and reservoirs that feed water treatment facilities. A 2019 University of New Mexico study found microplastics in 94% of US tap water samples.

Can water filters remove microplastics from drinking water?

Yes, but only certain filter types. Reverse osmosis (RO) systems remove 90-99% of microplastics because they filter particles down to 0.0001 microns. Standard carbon filters don't effectively remove microplastics. Pitcher filters and basic tap filters also fail to remove most microplastic particles. For microplastic removal, RO is the only reliable option for home use.

Are microplastics in drinking water dangerous to health?

Research is ongoing, but early evidence is concerning. The 2023 Stanford Medicine study found microplastics in 60% of cardiac surgery patients' heart tissue. A 2022 study detected microplastics in human blood for the first time. Microplastics can carry toxic chemicals (BPA, phthalates) and may cause inflammation. While long-term health impacts aren't fully understood, the presence of plastics in vital organs like the heart raises significant health concerns.

Should I be worried about microplastics in UK tap water?

UK tap water contains microplastics, though exact levels aren't routinely monitored. The UK has no legal limits for microplastics in drinking water. If you're concerned about long-term exposure, especially given the Stanford Medicine findings of microplastics in heart tissue, a reverse osmosis system is the most effective home filtration option. Standard carbon filters and water softeners don't remove microplastics.

Microplastics Found in Human Hearts During Surgery

In August 2023, researchers published a study that should make everyone pause before dismissing water filtration as "unnecessary." For the first time, scientists detected microplastics in human heart tissue—not just in one or two patients, but in 60% of the 257 cardiac surgery patients they examined.

This wasn't a theoretical risk or an animal study. Cardiac surgeons were finding tiny plastic particles embedded in the very tissues they were operating on. The implications are profound, and drinking water is one of the primary exposure routes.

What the Research Found

The study, published by researchers at Capital Medical University in Beijing and featured by the American Chemical Society, examined heart tissue samples from patients undergoing cardiac surgery. Here's what they discovered:

Key Findings:

Detection rate: Nearly 60% of patients had microplastics in their heart tissue
Particle size: 20-500 micrometers wide (about the width of a human hair)
Types found: Nine different types of plastics, including polyethylene (58% of patients) and PVC (12%)
Location: Found in multiple heart tissues and blood samples, both before and after surgery
Health link: Patients with microplastics in arterial plaque had significantly higher risk of cardiovascular events

Perhaps most concerning: the study found microplastics in tissues before surgery began, proving these particles weren't introduced during the medical procedure—they were already embedded in patients' bodies.

It's Not Just Hearts

Subsequent research has found microplastics throughout the human body. A January 2025 Stanford Medicine review documented microplastic detection in:

Brain tissue (at higher concentrations than liver or kidney)
Lungs (found in people undergoing surgery)
Blood clots surgically removed from arteries in the heart, brain, and deep veins
Placenta (raising concerns about fetal exposure)
Liver, kidneys, testicles, lymph nodes, and bone marrow

A University of New Mexico study in February 2025 found "alarmingly high levels" of microplastics in human brains—higher than in any other organ studied. The plastic accumulation appears to be growing over time.

The Water Connection

Microplastics enter our bodies through three main routes: drinking water, food, and air. While we can't control all exposure sources, drinking water is one we can address.

Here's the problem:

The UK does not currently test for microplastics in tap water. The Drinking Water Inspectorate's comprehensive testing regime—which achieves 99.98% compliance with safety standards when water leaves treatment works—doesn't include microplastics. We simply don't know how much is in our water supply or what happens in the distribution network.

Studies in other countries have found microplastics in 83% of tap water samples worldwide (Orb Media 2017 global study). There's no reason to believe UK water is different. The particles come from degrading plastic pipes, water bottles, synthetic clothing fibers, and environmental contamination.

What You Can Do About It

The good news: reverse osmosis (RO) filters remove 99%+ of microplastics from drinking water. The semi-permeable membrane used in RO systems has pores so tiny (0.0001 micron) that only water molecules can pass through. Microplastics—even the smallest ones—are blocked and flushed away.

Filter Effectiveness for Microplastics:

Reverse Osmosis: Removes 99%+ of microplastics (most effective)
Carbon Block Filters: Remove large microplastics only (limited effectiveness)
Sediment Filters: Remove large microplastics only (limited effectiveness)
Pitcher Filters (like Brita): Minimal to no microplastic removal
Water Softeners: Do not remove microplastics

If you're concerned about microplastic exposure—and given the emerging research, that's a reasonable concern—an RO system is currently the only proven solution for drinking water. Under-counter RO systems typically cost £200-£500 and provide comprehensive protection against microplastics, PFAS, lead, and other contaminants. Compare all filter types to find the right system for your needs.

Learn more about how reverse osmosis works and what it removes in our Water Filtration 101 guide.

The Bigger Picture

This research is still emerging, and we don't yet know the full health implications of microplastic accumulation in human organs. The cardiovascular link is concerning, but more studies are needed to establish causation and understand long-term effects.

What we do know: microplastics are accumulating in our bodies, drinking water is a significant exposure route, and we have the technology to remove them. Whether you choose to filter your water is a personal decision, but it should be an informed one.

Key Takeaways:

✓ Microplastics found in 60% of cardiac surgery patients' heart tissue
✓ Also detected in brain, lungs, blood, liver, kidneys, and other organs
✓ UK does not currently test for microplastics in tap water
✓ Reverse osmosis filters remove 99%+ of microplastics
✓ Standard carbon and pitcher filters provide minimal protection
✓ Health implications still being researched, but cardiovascular links emerging

References

American Chemical Society (Aug 2023): "Microplastics found in human heart tissues"

Yang et al. (2023): "Detection of Various Microplastics in Patients Undergoing Cardiac Surgery"

Stanford Medicine (Jan 2025): "Microplastics and our health: What the science says"

Nature (Mar 2024): "Landmark study links microplastics to serious health problems"

Microplastics Found in Human Hearts During Surgery: What This Means for Your Water

What the Research Found

Key Findings:

It's Not Just Hearts

The Water Connection

Here's the problem:

What You Can Do About It

Filter Effectiveness for Microplastics:

The Bigger Picture

Key Takeaways:

References

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