1 Glass or plastic: Which is really safer?
For years, glass has been considered the healthier and more eco-friendly alternative to plastic – elegant, recyclable and perceived as “pure”.
However, recent studies show that even glass bottles contain microplastics, often in greater quantities than those found in plastic or cans.
A study conducted by ANSES1 (the French agency for health safety) revealed that glass-bottled beverages show higher levels of plastic particles compared with other types of packaging. A surprising result – one that overturns the assumptions of many consumers.
2 What the results show
The findings from the ANSES study are clear:
- In carbonated drinks, iced tea and beer sold in glass bottles, an average of 100 particles per litre were found.
- The same beverages packaged in plastic bottles or cans contained 5 to 50 times fewer particles.
- Water showed lower values overall: around 4.5 particles per litre in glass bottles and 1.6 in plastic.
3 Why there are microplastics in glass bottles: the real culprit
The ANSES study highlights that the issue isn’t the glass itself, but rather the metal caps coated with varnish. During manufacturing and storage, the caps rub against one another. This friction causes invisible micro-scratches that release plastic fragments, which are then found in the drinks.
The main source of microplastics in bottled water is therefore the varnish used on the caps. The particles detected in both water and soft drinks effectively matched the colour and chemical composition of the coating used on the caps – clear proof that the contamination originates precisely there.
Another study2 published in PNAS, detected up to 240,000 particles per litre in bottled water samples – most of which nanoplastics, far smaller and potentially more harmful, capable of crossing cellular barriers.
The fact that microplastics are also present in glass-bottled water is a warning sign: Daily exposure is real, and it’s important to be aware of it.
4 What can producers do?
The studies mentioned above suggest several practical solutions to reduce contamination:
- Clean the caps before sealing (even a simple blast of compressed air can reduce particle levels)
- Change the materials and varnishes used for coatings
- Reduce friction between caps during storage and transport
Simple measures, but ones that could in themselves significantly lower microplastic levels.
5 Tap water or bottled water: Which is better?
A question many people ask: What’s the best water to drink – tap or bottled?
Italy continues to lead the ranking in Europe (and the world) for bottled water consumption. In 2023, total consumption reached around 14.7 billion litres3. Although the Italian water supply network is well-regulated and safe, only 29% of Italians report drinking tap water daily (ISTAT data4), while 43% rely exclusively on bottled water5.
Consuming bottled water has a major environmental impact; it is estimated that around 13.5 billion bottles6 (plastic and glass) are used in Italy every year.
A recent Altroconsumo test7 (on bottled mineral water) also found, in some brands, traces of undesirable substances such as PFAS – highly persistent chemical pollutants that do not degrade easily and tend to accumulate in living organisms. For this reason, they are often called “forever chemicals”. Although not microplastics, the results confirm that packaged water is not automatically free from environmental contaminants.
According to Legambiente8, tap water supplied through the public network often contains fewer microplastics and has a much lower environmental impact than bottled water.
6 Choosing your water means choosing mindfully
The issue of microplastics in bottled water encourages us to look beyond appearances and rethink long-standing habits. There is no such thing as a “perfect” container – what matters is having clear information and adopting informed behaviour.
Supporting this view is a very recent study9 (published in August 2025 in Science Direct), which analysed the presence of microplastics in various beverages sold in France, including water, soft drinks, tea, lemonade, beer and wine. The research team set out not only to measure the degree of contamination in these beverages, but also to determine whether the type of packaging played a role – be it plastic, glass, cans, cartons or other materials. Specifically, with regard to bottled water, the study showed, as noted earlier, that glass is not always the “cleanest” choice; in fact, glass bottles tended to contain more microplastics than plastic ones. Mineral and sparkling waters also showed slightly higher contamination levels than still or spring waters. Another interesting finding was that the differences did not depend solely on the packaging material, but also on the brand – some waters contained higher concentrations, others lower. In all cases, the microplastics found were tiny and variable in size, but nonetheless always present, confirming that no container is truly “immune” to the problem.
The environmental organisation Agir pour l’Environnement, in a 2022 study10 carried out on several brands of mineral water, had already found that 78% of bottles contained microplastics.
7 What can we do in our everyday lives?
The following everyday practices can be helpful in minimising exposure to microplastics:
- Choose tap water whenever it is safe and regularly monitored in your area.
- Use certified home filters to improve the quality of drinking water.
- If opting for bottled water, check the type of cap and choose brands that use closures without synthetic varnishes.
- Avoid leaving bottles in the sun or near heat sources.
Remember: glass doesn’t automatically mean the absence of microplastics, and plastic isn’t always the worse option. The right question is no longer “Is glass better than plastic?” but rather: “Which choice truly reduces environmental impact – and my exposure to microplastics?”
