Contents of fluoride, lead, copper, chromium, arsenic and cadmium in Chinese Pu-erh tea

In order to assess safety for consumers and the levels of contamination in Pu-erh tea, the authors studied the contents of fluoride, lead, copper, chromium, arsenic and cadmium in 56 Chinese samples of Pu-erh tea collected from Dali City, Lincang City, Xishuangbanna City, Simao City and Dehong City in Yunnan province. The ranges obtained for the elements analyzed were 80.2-151.6 mg kg− 1 (fluoride), 0.66-4.66 mg kg− 1 (lead), 14.8-19.3 mg kg− 1 (copper), 1.95-4.98 mg kg− 1 (chromium), 0.07-0.25 mg kg− 1 (arsenic) and 0.023-0.130 mg kg− 1 (cadmium). The mean leached analyte concentrations in tea infusion were 523.86 μg L− 1 for fluoride, 5.70 μg L− 1 for lead, 43.18 μg L− 1 for copper, 13.67 μg L− 1 for chromium, 0.43 μg L− 1 for arsenic and 0.17 μg L− 1 for cadmium after the tea leaves were brewed twice with boil water in a ratio of 1 g/50 ml for 5 min. The mean dissolving rates of fluoride, lead, copper, chromium, arsenic, and cadmium were 45.8%, 24.6%, 26.2%, 35.2%, 30.8% and 27.4%, respectively. Significant differences for the content of the studied elements except copper were generally observed with different Pu-erh tea's habitats. Pu-erh compressed tea had lower lead levels than loose tea. Based on a 70 kg individual consuming 15 g of Pu-erh tea daily or 105 g Pu-erh tea weekly, the dietary intake of the studied elements was below the safe limits recommended by various authorities. This suggested that under the current dietary intake, there are no possible health risks to Pu-erh tea drinking consumers.

► The contents and dissolving rates of the studied elements were determined. ► Pu-erh compressed tea generally had much lower lead levels than loose tea. ► The dietary intakes of the studied elements pose no risk to human health.