Research results have shown that tea leaves can help purify water. There are also expectations that drinking tea in areas with severe soil pollution can prevent heavy metal poisoning.
Vinayak Dravid, a professor at Northwestern University in the U.S., reported research findings on the 24th (local time) that tea leaves can remove heavy metals from water.
Tea is a beverage that humanity has enjoyed for thousands of years. According to literature, its origins trace back to the Shang Dynasty in China in the 17th century B.C. Tea has also been used in Eastern cultures as a medicinal herb to treat illnesses and maintain health. Recently, research results have emerged suggesting that compounds in tea leaves may be effective in preventing strokes and cardiovascular diseases.
The research team conducted experiments to determine whether tea leaves could remove pollutants from water. They used traditional teas such as black tea, green tea, oolong tea, and white tea, as well as herbal teas like chamomile and rooibos. The team measured the concentration changes after steeping tea leaves in water containing heavy metals such as lead, chromium, copper, zinc, and cadmium at various concentrations.
The experiment results showed that the steeped tea water had reduced levels of heavy metals. Among the types of tea, black tea exhibited the most remarkable pollutant removal effect. Black tea is classified as a fully fermented tea, with more than 80% of the tea leaves fermented. The processing method, when in powdered form, reduced heavy metal concentration more effectively than using whole leaves.
The research team noted that 'tea leaves have tiny pores, and during the processing of black tea, the leaves wrinkle, leading to the opening of these pores.' They added, 'It appears that the increased surface area of the tea leaves adsorbs and removes heavy metals.'
Among the types of heavy metals, the removal effect of lead was the most significant. Heavy metal concentrations were observed to decrease by about 15% within 5 minutes during the tea steeping process. Using more tea leaves or extending the steeping time can further enhance the lead removal effect.
The research team evaluated that this study proved tea's potential to help prevent the accumulation of heavy metals in the body while also being used for water quality improvement in regions with severe water pollution. In particular, it is expected that using tea leaves for lead removal will have a significant concentration reduction effect.
The research team expressed hope that 'even drinking just one cup of tea a day can help prevent heavy metal accumulation and poisoning.' They also indicated that 'the reason tea lowers the risk of strokes and cardiovascular diseases may be related to its heavy metal removal effect.'
The research findings were published in the journal 'ACS Food Science & Technology' by the American Chemical Society (ACS).
References
ACS Food Science & Technology (2025), DOI: https://doi.org/10.1021/acsfoodscitech.4c01030