A recent study by the ANSES Laboratory for Food Safety has uncovered a surprising source of microplastic contamination in bottled drinks.

The research, conducted by the laboratory's Boulogne-sur-Mer unit, found that beverages in glass bottles have higher levels of microplastics compared to those in plastic bottles, cartons, or cans.

For most drinks, including lemonade, iced tea, and beer, glass bottles contained around 100 microplastic particles per litre, five to 50 times more than other containers that were surveyed.

In contrast, water and wine showed relatively low levels of microplastics, regardless of the packaging. An average of 4.5 particles per litre was found in glass bottles, and 1.6 particles per litre in plastic bottles and cartons. 

The study suggests that microplastics in drinks from glass bottles with caps likely originate from the paint on the metal caps. The paint's colour and composition matched the microplastics found in the beverages, and the caps exhibited tiny, friction-caused scratches.

To investigate ways to reduce microplastic levels, the laboratory tested various cleaning methods for bottle caps.

"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.

The findings highlight a potential action point for manufacturers to address microplastic contamination. Measures could include improving cap storage to prevent friction, altering the paint composition, or implementing thorough cap cleaning before sealing bottles.

A recent paper published on the Microplastics and Nanoplastics forum has called for an approach to scientific engagement with communities in addressing the escalating plastic pollution crisis.