Lead, cadmium, arsenic, mercury and copper levels in Chinese Yunnan Pu'er tea.

The Yunnan region of China produces a distinctive variety of Pu'er tea, which is consequently labeled as a Chinese geographic indication product. In this study, the safety of Chinese Yunnan Pu'er tea with regard to heavy metal content was evaluated in 30 different brands of Pu'er tea, including 150 commercial samples. Metal levels in the Pu'er tea samples followed the order: copper (12-22 µg/g) > lead (0.26-3.2 µg/g) > arsenic (0.035-0.24 µg/g) > cadmium (0.0059-0.085 µg/g) > mercury (<0.010 µg/g). Mercury was not detected in 17 of the brands of Pu'er tea. Metal-to-metal correlation studies showed that there were no significant correlation between metal pairs. Based on current safety standards, the low levels of metals detected in these Pu'er tea samples mean they are safe for human consumption.