Boiling Water Can Remove Up to 90% of Microplastics and Nanoplastics

Tiny plastic particles are reaching deep into our bodies in worrying amounts, especially through the food and drinks we consume.

In 2024, researchers in China identified a straightforward, effective way to remove them from water. The team tested both soft water and hard tap water, which contains more minerals.

They introduced nanoplastics and microplastics into the water, then boiled it and filtered out the resulting precipitates.

"Tap water nano/microplastics (NMPs) escaping from centralized water treatment systems are of increasing global concern, because they pose potential health risks to humans via water consumption," the researchers write in their published paper.

Watch the video below for an overview of the findings:

Boiling water to remove nanoplastics and microplastics

In certain tests, boiling and filtering removed up to 90 percent of NMPs, although performance depended on the water type.

The major advantage, naturally, is that most people already have everything needed in their kitchen.

"This simple boiling water strategy can 'decontaminate' NMPs from household tap water and has the potential for harmlessly alleviating human intake of NMPs through water consumption," write biomedical engineer Zimin Yu from Guangzhou Medical University and colleagues.

Hard tap water removed a larger share of NMPs because heating it naturally produces limescale, or calcium carbonate.

This chalky material, often visible inside kitchen kettles, coats the plastic particles as temperature changes cause calcium carbonate to come out of solution. The resulting crust effectively traps the plastic fragments.

"Our results showed that nanoplastic precipitation efficiency increased with increasing water hardness upon boiling," the team writes.

"For example, from 34 percent at 80 mg L⁻¹ to 84 percent and 90 percent at 180 and 300 mg L⁻¹ of calcium carbonate, respectively."

Even soft water, which contains less dissolved calcium carbonate, captured around a quarter of the NMPs.

The researchers say that lime-coated plastic particles could then be removed with a simple filter, such as a stainless-steel tea strainer.

Earlier studies have detected fragments of polystyrene, polyethylene, polypropylene and polyethylene terephthalate in drinkable tap water, which we consume every day in differing quantities.

To challenge the approach further, the researchers added still more nanoplastic particles, and their numbers were effectively reduced.

"Drinking boiled water apparently is a viable long-term strategy for reducing global exposure to NMPs," write Yu and team.

"Drinking boiled water, however, is often regarded as a local tradition and prevails only in a few regions."

As plastics continue to spread across the world, the scientists hope boiling drinking water could become more widely practised.

Microplastics in drinking water and the environment

Minute pieces of plastic are becoming an ever-larger problem. Microplastics come from clothing, kitchen utensils, personal-care products and innumerable other everyday items.

Their resilience means they persist in the environment, including inside human bodies.

Many people around the world are already contaminated with microplastics, while daily exposure continues because these insidious particles face little regulation.

A 2025 literature review from The University of Texas at Arlington found that drinking water may account for a substantial proportion of microplastic exposure, because wastewater treatment plants still do not remove microplastics effectively.

Since plastic manufacture began, approximately 9 billion metric tonnes of plastic have been produced worldwide. Much of it has gradually degraded into smaller and smaller pieces without ever properly breaking down, creating a fine plastic dust that now permeates the planet.

The new review suggests that wastewater treatment plants do remove many of these tiny particles, but not enough of them.

What microplastics may mean for health

Precisely how harmful this plastic is to our bodies remains uncertain, but it is clearly not the healthiest of snacks.

Plastics have already been associated with changes to the gut microbiome and the body's antibiotic resistance.

The study team would like further research into whether boiled water can prevent artificial materials entering our bodies, and potentially offset some of the troubling microplastic effects now being identified.

"Our results have ratified a highly feasible strategy to reduce human NMP exposure and established the foundation for further investigations with a much larger number of samples," Yu and colleagues conclude.

The study was published in Environmental Science & Technology Letters.

An earlier version of this article was published in March 2024.