Determination of lead, cadmium and arsenic in infusion tea cultivated in north of Iran

Tea is one of the most common drinks in all over the world. Rapid urbanization and industrialization in recent decades has increased heavy metals in tea and other foods. In this research, heavy metal contents such as lead (Pb), cadmium (Cd) and arsenic (As) were determined in 105 black tea samples cultivated in Guilan and Mazandaran Provinces in north of Iran and their tea infusions. The amount of heavy metals in black tea infusions were analyzed using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP - AES). The mean ± SD level of Pb in 5, 15 and 60 min in infusion tea samples were 0.802 ± 0.633, 0.993 ± 0.667 and 1.367 ± 1.06 mg/kg of tea dry weight, respectively. The mean level of Cd in 5, 15 and 60 min in infusion tea samples were 0.135 ± 0.274, 0.244 ± 0.46 and 0.343 ± 0.473 mg/kg of tea dry weight, respectively. The mean level of As in 5, 15 and 60 min in infusion tea samples were 0.277 ± 0.272, 0.426 ± 0.402 and 0.563 ± 0.454 mg/kg of tea dry weight, respectively. Also, the results showed that the locations and the infusion times influenced upon the amount of these metals (P < 0.05).