Determination of Arsenic, Cadmium and Lead Concentration in Teas, Commercialized in Rio De Janeiro, Brazil, and Their Transfer to Tea Infusion

About 75% of the estimated 2.5 milliontons of dried tea harvested annually in the world is manufactured as black tea. Black tea (Camellia sinensis) is one of the most widely popular nonalcoholic beverages consumed by over two-thirds of the world's population, due to its medicinal, refreshing and mild stimulating effects; besides the positive effects, studies have also shown that drinking tea can have negative effects on human health. From tea leaves, different types of tea are produced: black, green and white. These teas mainly differ in their degree of processing and composition. In the present study, it has been hypothesized that tea leaves contain amounts of As, Cd and Pb, but these elements are leached not from tea leaves to infusion. To verify this hypothesis, concentrations of As, Cd and Pb were determined in tea leaves and infusion and results were compared. Five different brandswere collected in supermarkets and then analyzed. The samples were digested in a microwave digester. After digestion, the determination of As, Cd, Pb in tea leaves and infusions were done by inductively coupled plasma mass spectrometry (ICP-MS). The concentration of As, Cd and Pb in tea leaves were 0.02-0.4 mg kg; 0.02-0.09 mg kg and 0.1-3.6 mg kg, and the concentration in tea infusions < 0.005-0.007mg L; < 0.005-0.007 mg L and 0.005-0.015 mg L, so there was almost no transfer from tea leaves metal content to infusion. The concentration of Pb in white tea leaves (0.8-3.6 mg kg) was higher than in green and black teas, and it was also higher than the limit established by Brazilian National Health Surveillance Agency (ANVISA) is of 0.6 mg kg. The concentration of As and Cd in leaves and infusion was below ANVISA limits 0.4 mg kg.