Glass bottles contaminate beverages with microplastics – study finds

FRANCE – The Boulogne-sur-Mer unit of the ANSES Laboratory for Food Safety has uncovered unexpected sources of microplastic contamination in bottled drinks, revealing surprising findings.

Microplastics are present in all beverages.

The study found that beverages in glass bottles have higher levels of microplastics compared to those in plastic bottles, cartons, or cans.

For instance, in glass bottles of cola, lemonade, iced tea, and beer, on average, there were around 100 microplastic particles per litre, reflecting five to 50 times lower concentrations in plastic bottles and cans.

Contrarily, the findings highlight that water and wine are less affected than other beverages. 

The level of microplastics in water is an average of 4.5 particles per litre in glass bottles and 1.6 particles per litre in plastic bottles and cartons.

Additionally, wine also contained a few microplastics, including glass bottles with corks. 

The research hypothesises that these plastic particles could come from the paint used on the metal bottle caps. 

The scientists noted that the microplastics found in the drinks were mostly the same colour and had the same composition as the paint on the caps, therefore indicating that these particles probably came from the paint covering the metal caps.

In support of the findings, the paint on these caps had tiny scratches that were invisible to the naked eye and had probably been caused by friction between the caps when they were stored before use, also indicating the source of the microplastics.

The laboratory tested various cleaning methods for bottle caps to explore possible ways to reduce microplastic levels.

“We studied three scenarios,” explained a PhD student involved in the research.

By cleaning the bottles and caps in different ways, they found that the number of microplastic particles could be significantly reduced.

According to the research, various measures have been highlighted that manufacturers can easily take to address a source of microplastics in drinks.

These measures include adjusting the storage conditions to minimise friction, modifying the paint composition, or implementing thorough cap cleaning before sealing bottles, offering potential solutions to the challenge.

Measures could include improving cap storage to prevent friction, altering the paint composition, or implementing thorough cap cleaning before sealing bottles.

Considering these findings, manufacturers must reassess their assumptions about the purity of glass packaging and take proactive steps to minimise microplastic contamination, raising awareness about the issue.

Moving forward, manufacturers should prioritise science-backed innovations that minimise both ecological impact and consumer exposure to microplastics, thus striking a balance between sustainability, safety, and performance across all packaging types.

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