Guwahati: A study by scientists from Tea Research Association has found that the teas from Northeast India are safe to drink.
Samples collected from eight regions in east and northeast India, including Upper Assam, South Bank, Cachar, Tripura, Darjeeling, Terai, Dooars and North Bank, were found to have no inorganic mercury or uranium.
The study by scientists at TLabs, Tea Research Association, Kolkata published in Biological Trace Element Research journal says no inorganic mercury, as well as uranium, was detected in any tested tea samples from a total of 321 drier mouth samples collected during 2020–2021 from eight different regions (Darjeeling, Terai, Dooars, North Bank, Upper Assam, South Bank, Cachar, and Tripura) of Northeast India.
Northeastern states play a vital role in India’s tea production as well as the global scenario as they made up over 80 per cent of the total tea produced in India as well as 17 per cent of total global production in 2020.
Bappaditya Kanrar, scientist at TLabs, Tea Research Association, says elements are an integral part of the biochemical composition of any food, even tea. The acidic nature of tea-growing soil is also creating conditions more favourable to absorbing the metals in tea plants from the soil.
Apart from the soil, different anthropogenic activities like agricultural input and practices, and industrial growth also contribute greatly to the elemental concentration and composition.
“Among the 118 elements, around 70 can be analysed by Inductively Coupled Plasma Mass Spectrometry (ICP- MS) which we have screened in our earlier work and found the presence of 39 elements in the northeast Indian tea. Trace element contents of tea may have both beneficial and adverse effects on human health,” said Kanrar.
Scientific studies have already proved that presence of trace elements in tea is due to tea plants being grown in highly acidic soils, where trace elements are potentially more bioavailable for root uptake. Trace element contents of tea may have both beneficial and adverse effects on human health. Determination of trace elements in tea is normally done to judge their nutritional value and also to assess the risk against any probable health hazard. Even though drinking tea is a popular refreshment in many countries, the potential non-essential trace element intake from drinking tea has not been included in the dietary intake assessments.
“Keeping in view the growing awareness and concerns about trace elements in tea, most of the studies done either on specific toxic elements or essential elements or on specifc group of elements; hence, this present study aimed to generate elemental data on 24 elements, belong to 24 elements, belong to alkali metal (Li, Rb, Cs), alkaline earth metal (Be, Sr, Ba), transition metal (V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Cd, Hg), basic metal (Al, Ga, Sn, Tl, Pb), metalloid (As), non-metal (Se), and actinide (U) to assess the more accurate risk assessment associated with the consumption of the tea of these regions,” Kanrar told EastMojo.
The International Agency for Research on Cancer (IARC) has classified the metals based on their potential health risk. Most of the elements are non-carcinogenic or not classified (group 3); some elements like Pb and Co are classified as probable carcinogen (group 2A); and Ni, As, and Cd are classified as carcinogenic (group 1).
For non-carcinogenic elements non-carcinogenic risk of elements by evaluating the hazard quotient (HQ) and hazard index (HI) value which needs to be < 1 for safe consumption by human being. Carcinogenic risk assessment by evaluating the incremental lifetime cancer risk (ILCR) has to be assessed with the interpretation of very low level, low level, medium level, high level, and very high level of carcinogenic risk.
“Here in this study, we have done the non-carcinogenic as well as carcinogenic risk assessment of the studied elements. So, the study concluded that evaluating 24 elements of north-east Indian tea would not pose any significant carcinogenic as well as non-carcinogenic risk and other health hazard to human being and completely safe for consumption” Kanrar said.
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