Tea bags release millions of plastic particles during brewing

You might think of tea as a comforting, soothing ritual. But, scientists at Universitat Autònoma de Barcelona (UAB) have made a startling discovery – infusing tea through commercial tea bags might be releasing billions of nanoplastics and microplastics into your cup.

Recent research from the Mutagenesis Group in the UAB Department of Genetics and Microbiology highlights how polymer-based tea bags release microplastics and nanoplastics (MNPLs) during brewing.

For the first time, the study has shown that these particles can be absorbed by human intestinal cells, potentially entering the bloodstream and spreading throughout the body.

Source of plastic contamination in tea bags

Food packaging is a leading contributor to micro and nanoplastic pollution. Humans are primarily exposed to these particles through inhalation and ingestion.

This new study focuses on the significant release of MNPLs from commercially available tea bags when used to prepare an infusion.

The researchers discovered alarming levels of contamination:

• Polypropylene released around 1.2 billion particles per milliliter, with an average size of 136.7 nanometers.
• Cellulose released 135 million particles per milliliter, averaging 244 nanometers.
• Nylon-6 released 8.18 million particles per milliliter, averaging 138.4 nanometers.

These findings underline the importance of identifying and reducing plastic exposure through everyday items, like tea bags.

Analyzing plastic particles in tea bags

To characterize these particles, the researchers employed advanced analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA).

These methods allowed the team to examine the structure, size, and behavior of the particles in detail.

“We have managed to innovatively characterize 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,” explained UAB researcher Alba Garcia.

Human health at risk

For the first time, the team explored how MNPLs interact with human intestinal cells. To achieve this, they stained the particles to track their movement and exposed them to various types of intestinal cells in the lab.

The study revealed that mucus-producing intestinal cells absorbed the highest amount of these plastic particles from tea bags.

This was a significant finding because these cells play a protective role in the gut. Even more alarming was the observation that some particles managed to penetrate the cell nucleus, the part of the cell where genetic material is stored and regulated.

This discovery raises serious concerns about the long-term health effects of MNPL exposure. If these particles can reach the nucleus, they may interfere with cellular functions or genetic processes, potentially causing harmful outcomes over time.

The researchers also noted that intestinal mucus played a key role in helping the particles enter the cells. This finding suggests that individuals with frequent exposure to MNPLs – such as those from food or drink packaging – could face cumulative risks.

Chronic exposure might lead to widespread impacts on health, emphasizing the need for further research and preventive measures.

Calls for regulation and policy changes

The findings emphasize the urgent need for regulatory measures to minimize MNPL contamination in food packaging.

“It is critical to develop standardized test methods to assess MNPLs contamination released from plastic food contact materials and to formulate regulatory policies to effectively mitigate and minimize this contamination,” noted Alba Garcia and her team.

“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.”

This research on contamination in tea bags highlights the pressing need to prioritize food safety in the face of rising plastic use. By understanding and addressing microplastic and nanoplastic contamination, we can work toward protecting public health and the environment.

Making informed choices about products

This study sheds light on a hidden source of plastic pollution that affects everyday life. As tea drinkers worldwide sip from polymer-based tea bags, they may unknowingly expose themselves to billions of plastic particles.

The implications for human health are alarming, but this research offers a critical foundation for future studies and regulations.

Making informed choices about the products we use and supporting policies aimed at reducing plastic pollution are essential steps toward ensuring a safer, healthier future.

The study is published in the journal Chemosphere.

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