And they’re not just in your drinks: microplastics are showing up in your toothbrush, teeth aligners, and even chewing gum

In a surprising twist for consumers aiming to avoid plastic pollution and plastic bottles, a new French study has revealed that drinks stored in glass bottles contain even more microplastics than those in plastic bottles, cartons, or cans. Conducted by the Boulogne-sur-Mer unit of the ANSES Laboratory for Food Safety, the research points to a previously overlooked source of microplastics: the painted caps of glass bottles.

The study, published in the Journal of Food Composition and Analysis, looked at microplastic contamination in drinks such as water, soda, iced tea, wine, and beer, and examined how different packaging materials might influence contamination levels. Across the board, glass bottles were found to contain more microplastics, with popular beverages like cola and beer showing an average of 100 microplastic particles per litre—five to 50 times higher than in plastic bottles or cans.

“We were expecting the opposite result when we compared the level of microplastics in different drinks sold in France,” said Iseline Chaïb, PhD student in the Aquatic Food Safety Unit (SANAQUA, Boulogne-sur-Mer site), ANSES Laboratory for Food Safety.

“We then noticed that in the glass, the particles emerging from the samples were the same shape, colour and polymer composition – so therefore the same plastic – as the paint on the outside of the caps that seal the glass bottles,” she said.

Despite growing concern over microplastic exposure, toxicological reference data is still lacking, making it difficult to assess the exact health risks associated with the levels found. Some early studies find effects in the liver.

Entrepreneurs Solve This: Paint on Bottle Caps

The researchers traced the contamination to painted metal caps which contain a plastic coating on the interior. Microplastics discovered in the drinks matched the color and chemical makeup of the paint coating the caps. Microscopic scratches—likely caused by friction among the caps and their edges during storage—were identified as the mechanism for particle release.

To explore prevention, the scientists tested various cleaning methods: “We studied three scenarios,” explains Chaïb. “We cleaned the bottles and filled them with filtered water so that no microplastics could be detected, then we placed caps on the bottles without treating the caps, after blowing on the caps with an air bomb, or after blowing air and rinsing the caps with filtered water and alcohol.”

Results showed:

• 287 particles per litre in bottles with uncleaned caps

• 106 particles per litre after air was blown on the caps

• 87 particles per litre when blowing was followed by rinsing

The researchers suggest simple steps in cap preparation or redesigning paint compositions could significantly reduce contamination. Until the problems are solved are we back to drinking from springs and filtering our own water at home?

The Hidden Microplastics in Your Mouth

While microplastics in beverages are alarming, the problem goes beyond the bottle. Reports by Green Prophet have highlighted growing evidence that common dental and hygiene products are also sources of daily microplastic exposure:

• Teeth aligners and retainers made from thermoplastics can shed microplastics through wear, particularly in hot liquids or during overnight use. A 2024 study reviewed by Green Prophet warned that long-term exposure to heated plastics in the mouth may leach hormone-disrupting chemicals.

• Chewing gum, often made from synthetic rubber (a plastic polymer), can release microscopic plastic particles with every chew. Unlike traditional chicle gum, modern brands contain industrial polymers that may degrade in the mouth, though few regulations require manufacturers to disclose them.

• Toothbrushes, especially nylon-bristle varieties, can fray and break down over time. According to a Green Prophet special report, worn toothbrushes can shed fibers directly into the mouth, where they may be swallowed or absorbed into oral tissues. Advice? Use a miswak?

These microplastics don’t simply pass through the body. Emerging research shows that particles smaller than 5 microns can cross cellular membranes and may accumulate in the bloodstream, lungs, or even the brain.

Glass Isn’t Always Greener

Even beverages like wine and bottled water—often seen as “cleaner” when packaged in glass—showed measurable microplastic contamination. Water in glass bottles had 4.5 particles per litre, compared to 1.6 in plastic bottles and cartons. Wine sealed with corks contained minimal microplastics.

The findings from ANSES suggest that glass bottle manufacturers can—and should—take swift action, particularly by rethinking the materials and handling of their bottle caps. Some companies such as Tipa and Balena are already leading the way in developing bio-plastics. The problem with plastics is not in dry packaging but in wet ones, such as liquids in bottles. Bio-plastics do and are meant to decompose over time, presenting a challenge in the bottling industry.

For consumers trying to reduce their exposure to microplastics, choosing glass may not be a guaranteed safeguard. And while the health risks are still under study, the evidence is mounting that microplastic exposure is not just a planetary issue—it’s a personal one.

The post Glass Bottles May Contain More Microplastics Than Plastic or Cans, New French Study Finds appeared first on Green Prophet.

When old food packaging, discarded children’s toys and other mismanaged plastic waste break down into microplastics, they become even harder to clean up from oceans and waterways.

These tiny bits of plastic also attract bacteria, including those that cause disease. In a study in ACS Nano, researchers describe swarms of microscale robots (microrobots) that captured bits of plastic and bacteria from water. Afterward, the bots were decontaminated and reused.

The size of microplastics, which measure 5 millimeters or less, adds another dimension to the plastic pollution problem because animals can eat them, potentially being harmed or passing the particles into the food chain that ends with humans.

So far, the health effects for people and micrplastics are not fully understood. However, microplastics themselves aren’t the only concern. These pieces attract bacteria, including pathogens, which can also be ingested. To remove microbes and plastic from water simultaneously, Martin Pumera and colleagues turned to microscale robotic systems, comprised of many small components that work collaboratively, mimicking natural swarms, like schools of fish.

To construct the bots, the team linked strands of a positively charged polymer to magnetic microparticles, which only move when exposed to a magnetic field. The polymer strands, which radiate from the surface of the beads, attract both plastics and microbes. And the finished products — the individual robots — measured 2.8 micrometers in diameter. When exposed to a rotating magnetic field, the robots swarmed together.

By adjusting the number of robots that self-organized into flat clusters, the researchers found that they could alter the swarm’s movement and speed.

In lab experiments, the team replicated microplastics and bacteria in the environment by adding fluorescent polystyrene beads (1 micrometer-wide) and actively swimming Pseudomonas aeruginosa bacteria, which can cause pneumonia and other infections, to a water tank.

Next, the researchers added microrobots to the tank and exposed them to a rotating magnetic field for 30 minutes, switching it on and off every 10 seconds. A robot concentration of 7.5 milligrams per milliliter, the densest of four concentrations tested, captured approximately 80% of the bacteria.

Meanwhile, at this same concentration, the number of free plastic beads also gradually dropped, as they were drawn to the microrobots. Afterward, the researchers collected the robots with a permanent magnet and used ultrasound to detach the bacteria clinging to them. They then exposed the removed microbes to ultraviolet radiation, completing the disinfection. When reused, the decontaminated robots still picked up plastic and microbes, albeit smaller amounts of both.

This microrobotic system provides a promising approach for ridding water of plastic and bacteria, the researchers note.

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