Microplastics in glass bottles, plastic bottles and cans: what studies show

Are there microplastics in glass bottles? Yes – and in some drinks, there are even more than in plastic bottles or cans. This was revealed in 2025 by a study conducted by the French food safety authority ANSES; the particles in those bottles were thought to have come from the colouring in the crown caps. A study from Germany had already found microplastics in mineral water from all the types of packaging examined as early as 2018. This guide explains what the figures mean, what they do not mean, and what is known about cans.

What are microplastics?

The Federal Environment Agency defines microplastics as pieces of plastic smaller than 5 mm. A distinction is made between two types:

• Primary microplastics are manufactured in such small sizes – for example, base pellets for plastics production or granules in cosmetics such as exfoliants or toothpaste.
• Secondary microplastics are formed when larger pieces of plastic break down physically, biologically or chemically. An example from the Federal Environment Agency: with every wash cycle, up to 2,000 synthetic fibres from fleece clothing end up in the sea via waterways, because sewage treatment plants do not filter them out.

The Federal Institute for Risk Assessment states that the typical size range is from 1 micrometre to 5 mm, and emphasises that the figures are not always consistent. It cites tyre and road wear, emissions from waste disposal and paint abrasion as the main sources of secondary microplastics.

The study from Germany: mineral water in different types of packaging

In 2018, researchers led by D. Schymanski analysed mineral water from 22 reusable and single-use plastic bottles, 3 cartons and 9 glass bottles purchased from German supermarkets. They found microplastics in every type of packaging; almost 80 per cent of the particles were between 5 and 20 micrometres in size. Particles smaller than 20 micrometres cannot be detected by the infrared method used in earlier studies; the researchers therefore employed micro-Raman spectroscopy.

Important for interpretation: only the reusable bottles differed statistically significantly from the blank value. In these, the particles consisted predominantly of PET and polypropylene – the materials used for the bottle and cap. Other plastics, such as polyethylene, were found in water from cartons and glass bottles; the authors attribute this to the polyethylene coating on the cartons and to lubricants on the closures.

The study from France: drinks in glass, plastic and cans

In 2025, ANSES analysed drinks such as water, lemonade, iced tea, wine and beer in various types of packaging. The result: microplastics were found in all drinks, but there were generally more in glass bottles than in plastic bottles, cartons or cans.

• Cola, lemonade, iced tea and beer in glass bottles: on average, around 100 particles per litre – in plastic bottles and cans, five to fifty times fewer.
• Water: relatively low levels, regardless of the packaging – 4.5 particles per litre in glass bottles, 1.6 in plastic bottles and cartons.
• Wine: also contains few microplastics, even in glass bottles with corks.

The researchers suspect that the source is the paint on the metal bottle caps: the particles were mostly the same colour and composition as the paint, and the caps showed tiny scratches, presumably caused by friction during storage. If the caps were blown clean with air before sealing, the particle count in the test fell from 287 to 106 particles per litre, and to 87 with additional rinsing. Manufacturers could also change the way the caps are stored to avoid friction, or use a different colour.

What is being criticised about the figures

A group of international researchers led by Jane Muncke of the Food Packaging Forum published a commentary on the ANSES study in September 2025. The commentary focuses on two key points:

• Per litre: If you work it out per litre, small containers appear to have a greater environmental impact because they have a larger surface area in relation to their contents – and the glass bottles in the study were mostly smaller than the plastic bottles containing the same type of drink.
• Only the final packaging: microplastics may also originate from filling lines and storage tanks prior to filling; the comparison did not take this into account.

Added to this is a fundamental limitation: according to the BfR, there are as yet no reliable methods for determining the quantity and composition of microplastics in food. Studies using different methods can therefore only be compared to a limited extent.

And what about the can?

In the ANSES study, the levels found in can cola, lemonade, iced tea and beer were significantly lower than those in glass bottles with crown caps. However, no packaging is free of microplastics: ANSES found particles in all the drinks.

Beverage cans have an internal coating. Amongst other materials, epoxy resins produced using bisphenol A (BPA) have been used for such coatings in beverage cans. Since 20 January 2025, the EU has banned BPA in food contact materials; a transition period until 20 July 2026 applied to most products. Our cans also have an internal coating, the compatibility of which with every beverage is tested prior to filling. More information on bisphenol A can be found in the article ‘Bisphenol A in cans’.

Are microplastics dangerous?

As things stand, it is not possible to answer this question with certainty. The BfR states that there is as yet no conclusive evidence of health risks associated with long-term exposure; it expects our understanding of the issue to improve significantly in the coming years. In the BfR’s feeding studies, various microplastic particles showed no harmful effects on intestinal tissue or other organs in mice – even at levels far exceeding what appears realistic for humans. ANSES also emphasises that, without toxicological reference values, it is not possible to say whether the levels found pose a health risk.

Humans can ingest microplastics via the air, dust, drinking water, food and cosmetics; they have been detected in, amongst other things, mineral water, honey, beer, salt, fruit, fish and seafood. In addition to the food itself, packaging materials, manufacturing processes and food preparation can contribute to the presence of microplastics.

What you can do yourself

• Don’t rely on a single figure: the studies use different measurement methods and can only be compared to a limited extent.
• Water is only slightly contaminated: in the ANSES study, water in all types of packaging was found to be in the low range.
• A critical view of reusable plastic: In the German study, only water from reusable plastic bottles was found to be significantly above the blank value.

The ‘Why Dose?’ page explains why we chose the can.

Frequently Asked Questions

Sources

1. Federal Environment Agency: What are microplastics?, accessed 16 September 2026. umweltbundesamt.de
2. Federal Institute for Risk Assessment (BfR): Microplastics: Facts, Research and Unanswered Questions, FAQs dated 19 June 2024. bfr.bund.de
3. Schymanski D, Goldbeck C, Humpf HU, Fürst P – Water Research 129 (2018): Analysis of microplastics in water by micro-Raman spectroscopy: Release of plastic particles from different types of packaging into mineral water, 2018. doi.org
4. ANSES (France): Glass bottle caps contaminate drinks with microplastics, 25 June. anses.fr
5. Food Packaging Forum: Comment raises concerns about a study which found that glass bottles contain more microplastics, 25 September 25. foodpackagingforum.org
6. European Commission (Access2Markets): EU ban on the use of and trade in bisphenol A from 20 January 2025, accessed 16 September 2026. trade.ec.europa.eu