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Researchers Investigate How Tea Substance Interacts with Heavy Metals, May Contribute to Removing Contaminants from Water in a Simple and Effective Way
Tea is known for its health benefits, including reducing depression and the risk of diabetes. Now, a new study conducted at Northwestern University in the United States indicates that the beverage may also remove heavy metals from water during brewing.
The research was conducted by Professor Vinayak Dravid and PhD student Benjamin Shindel. The study analyzed the effect of different types of tea on the removal of lead, chromium, copper, zinc, and cadmium.
How The Study Was Conducted
The scientists provided specific amounts of heavy metals to clean water. Then, the water was heated just before boiling. Next, they introduced tea leaves, both loose and in commercial tea bags, and let them steep for periods ranging from a few seconds to 24 hours.
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After the brewing time, the samples were studied to check for a reduction in the concentration of the metals. True teas like black, green, oolong, and white were tested, as well as herbal varieties like chamomile and rooibos. Different materials for tea bags were also evaluated, including cotton, nylon, and cellulose.
Research Results
The study concluded that a typical cup of tea — brewed with a bag steeped in a mug of hot water for three to five minutes — managed to remove an average of 15% of the concentrations of heavy metals.
This effect was observed even in highly contaminated samples, as they contained lead at levels of up to 10 parts per million.
The researchers also noted that longer steeping times resulted in the removal of an even greater amount of metals. However, they pointed out that most people do not steep tea for such prolonged periods.
How Metals Are Removed
The ability of tea to reduce metals in water is related to the structure of the dried leaves. They have a wrinkled and porous surface, which provides a large area for the adhesion of metallic ions present in the water. These ions get trapped in the leaves and are discarded with them after brewing the tea.
The effect was similar for all types of tea tested since the process does not involve complex chemical reactions. Additionally, tea bags made of cotton and nylon did not show significant impact on the removal of the metals.
However, the biodegradable cellulose bags, which have a large active surface area, managed to adsorb a specific amount of metallic ions.
Tea as a Healthy Option
Despite the promising results, the researchers warn that tea cannot be used for large-scale water decontamination. However, including tea in the diet may bring long-term health benefits.
PhD student Benjamin Shindel suggests that increased tea consumption could, over time, reduce exposure to heavy metals in the population. This may be linked to lower rates of diseases associated with contamination by these elements, such as heart problems and strokes.
The researchers emphasize that more studies are needed to fully understand the effects of tea on the absorption of heavy metals in the human body. Nonetheless, the discovery adds another reason to consider tea a healthy choice in everyday life.
With information from New Atlas.
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