Frequent opening of plastic soda bottles increases microplastic contamination, study reveals

A new report reveals a startling increase in the number of microplastics found in popular soda brands the more the plastic bottles are opened, posing potential health risks to consumers.

The findings, released by the French environmental group Agir pour l’Environnement, have raised new concerns about the safety of plastic bottles.

Six types of plastic particles detected in common branded drinks

The study, conducted by two independent laboratories, analysed Coca-Cola and Schweppes soft drinks, identifying six different types of plastic particles. These micro and nanoplastics were detected in varying amounts based on how often the bottle was opened, simulating typical consumer use.

Agir pour l’Environnement reported that “manufacturers declare only two polymers in contact with the beverage: polyethylene (PE) for the cap and PET for the bottle.” However, the discovery of additional plastic polymers has prompted the organisation to question the transparency of manufacturers and the oversight of health authorities.

Microplastic levels surge with increased bottle openings

The study’s results are particularly concerning for expatriates and residents across the EU, where plastic bottled beverages are a staple. Upon the first opening of a one-litre bottle, researchers found four microplastic particles in Coca-Cola and 4.6 particles in Schweppes. However, after the bottle was opened 20 times, these numbers skyrocketed to 46 and 62 particles per litre.

Most of the detected particles were smaller than 500 micrometres (µm), with a significant portion being under 100 µm. Particles as small as 50 µm were frequently linked to repeated openings. The report also highlighted the presence of a “large quantity” of nanoparticles, which have irregular shapes that may increase their interaction with human cells and other polymers.

The findings have reignited the debate over microplastics in consumer products, especially in the EU, where environmental and health standards are generally stringent. Agir pour l’Environnement has urged French authorities to establish stricter guidelines to limit plastic contamination in food and beverages.

This report follows the organisation’s previous study on plastic microparticles in bottled water brands sold in France, which brought significant public attention to the issue two years ago. At that time, it was estimated that individuals ingest between 39,000 to 52,000 microplastic particles annually through food alone. When considering inhalation, these figures could climb to between 74,000 and 121,000 particles per year.

Growing health concerns over microplastics

Although the full impact of microplastic exposure on human health remains under investigation, the increasing evidence of their presence in everyday items is cause for concern. As research continues, the need for stronger regulatory action and consumer awareness becomes ever more critical.