Study Warns Tea Bags Leach Microplastics and Chemicals into Brews

A recent study has revealed that plastic tea bags can release a significant number of microplastic particles and toxic chemicals into hot drinks, prompting researchers to issue a warning about potential health risks. Scientists from Recep Tayyip Erdogan University discovered that a single tea bag can release up to 2,500 microplastic particles into a cup of tea.

The study, published in the journal npj Science of Food, also found that these tea bags leach harmful chemicals such as Bisphenol A (BPA) and plasticizers like phthalate esters (PAEs) into the brew. The researchers noted that their measurement methods captured particles larger than 100 micrometres, suggesting the actual number of plastic pieces could be substantially higher.

BPA is an endocrine disruptor that can interfere with the body's hormonal system, potentially leading to weakened immunity, increased risk of obesity and diabetes, reduced fertility, and cardiovascular issues. Studies have also suggested a link between BPA exposure and impaired brain development, increasing the risk of conditions like ADHD and autism spectrum disorder. The research indicated that consuming just 500ml of tea brewed in plastic bags could mean ingesting 4.55 to 21.7 percent of the safe daily limit for BPA, which the study authors described as a "critical warning, particularly for vulnerable groups such as pregnant women and children."

Phthalate esters, particularly di(2-ethylhexyl) phthalate (DEHP), were also found in concerning levels. While DEHP has been shown to increase cancer rates in animals with long-term exposure, its effects on humans are less understood. The study authors expressed concern about the "carcinogenic risk potential due to DEHP exposure may pose a public health concern, particularly under scenarios of long-term/high-volume consumption."

In contrast, loose-leaf tea was found to contain considerably lower levels of microplastic contamination. A two-gram serving of loose tea contained only 0.3-2.4 particles, with most contamination likely stemming from plastic packaging used during farming or atmospheric dust. The microplastics found in the tea bags were identified as fibers, suggesting they originated from the plastic mesh material of the bags themselves.

While many tea bags are now made from plastic-free cellulose, some brands continue to use plastic mesh. The research team analyzed four popular Turkish bagged tea brands and 14 types of loose-leaf tea, brewing them in 95°C (203°F) water for three minutes to measure microplastic release and chemical concentrations. These findings suggest that consumers may reduce their exposure to microplastics by opting for loose-leaf tea over bagged varieties. The researchers also suggested rinsing tea bags under cold water before brewing as an additional measure to limit microplastic exposure.