Determination of Ni, Cu, Cd, Zn, Pb, Cr and Mn in some black and green tea leaves and their infusions available in Bangladeshi local markets

Tea is a highly common beverage worldwide. In addition to other particles, it contains a range of minerals and trace elements. Even though many are necessary for humans, some could be hazardous. Scientists have long been interested in the toxicity of trace metals and how they affect human health. By using Flame Atomic Absorption Spectrophotometer, the amounts of Ni, Cu, Cd, Zn, Pb, Cr, and Mn in eight black tea leaves, five green tea leaves, and their infusions were examined. The tea samples were collected from Bangladeshi local markets. The infusion time in boiling water was 5 and 10 minutes. Results revealed that the concentration ranges of Ni, Cu, Cd, Zn, Pb, Cr and Mn in black and green tea leaves and their infusions of 5 minutes and 10 minutes were 1.82 to 41.32, 13.54 to 29.87, 0.48 to 2.16, 0.30 to 36.52, 0.04 to 3.89, 0.00 to 4.95 and 112.67 to 187.98 ppm respectively. Concentrations of the elements found in samples were compared with maximum values reported by World Health Organization (WHO). To verify the accuracy of the work, standard reference material (SRM) and certified reference material (CRM) were also tested alongside tea samples. Geographical fluctuations, seasonal changes, chemical characteristics of the soil of the cultivated area, plant age, manufacturing, and packaging process are responsible for the variances in metal content of several tea brands. Cd, Pb, Cr, and Ni’s target hazard quotients (THQ) and the hazard index (HI) from drinking tea were both below one, indicating no risk to human health.