Commercial tea bags identified as major source of microplastics in infusions

Commercial tea bags identified as major source of microplastics in infusions
by Hugo Ritmico
Madrid, Spain (SPX) Jan 01, 2025

Plastic pollution continues to pose a critical challenge, with micro and nanoplastic (MNPLs) contamination emerging as a growing concern for both environmental and human health. Among the significant contributors to this contamination is food packaging, with human exposure primarily occurring through ingestion and inhalation.

Research conducted by the Mutagenesis Group at the Department of Genetics and Microbiology of the Autonomous University of Barcelona (UAB) has revealed a substantial release of micro and nanoplastics from commercially available tea bags during the preparation of tea. This finding identifies tea bags as a notable source of MNPLs exposure.

Massive Release of Plastic Particles During Tea Brewing

The study analysed tea bags made from nylon-6, polypropylene, and cellulose, identifying their potential to release vast quantities of particles into brewed tea. Key findings include:

- Polypropylene: Released approximately 1.2 billion particles per milliliter with an average size of 136.7 nanometers.

- Cellulose: Emitted about 135 million particles per milliliter with an average size of 244 nanometers.

- Nylon-6: Released 8.18 million particles per milliliter with an average size of 138.4 nanometers.

The team utilised advanced analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA), to characterise these particles. "We have managed to innovatively characterise these pollutants with a set of cutting-edge techniques, which is a very important tool to advance research on their possible impacts on human health," remarks UAB researcher Alba Garcia.

Cellular Interactions Raise Health Concerns

The study marked the first time these particles were exposed to human intestinal cells to assess their biological interactions. Results showed that mucus-producing intestinal cells demonstrated the highest uptake of MNPLs, with some particles even penetrating the cell nucleus, where genetic material is housed. This discovery underscores the role of intestinal mucus in pollutant uptake and highlights the need for further investigation into the potential long-term health effects of chronic MNPLs exposure.

Call for Standardised Testing and Regulatory Action

Researchers emphasised the urgency of developing standardised methods to evaluate MNPLs contamination from food-related plastics. They also stressed the need for policies to mitigate such contamination, especially as the use of plastics in food packaging continues to rise. "It is critical to develop standardised test methods to assess MNPLs contamination released from plastic food contact materials and to formulate regulatory policies to effectively mitigate and minimise this contamination. As the use of plastic in food packaging continues to increase, it is vital to address MNPLs contamination to ensure food safety and protect public health," researchers add.

The study provides a framework for using tea bag-derived MNPLs as surrogates for understanding real-life exposure scenarios, opening pathways for further exploration into their impacts on human health.

Research Report:Teabag-derived micro/nanoplastics (true-to-life MNPLs) as a surrogate for real-life exposure scenarios