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

Abstract

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 80.2–151.6mgkg−1 (fluoride), 0.66–4.66mgkg−1 (lead), 14.8–19.3mgkg−1 (copper), 1.95–4.98mgkg−1 (chromium), 0.07–0.25mgkg−1 (arsenic) and 0.023–0.130mgkg−1 (cadmium). The mean leached analyte concentrations in tea infusion were 523.86μgL−1 for fluoride, 5.70μgL−1 for lead, 43.18μgL−1 for copper, 13.67μgL−1 for chromium, 0.43μgL−1 for arsenic and 0.17μgL−1 for cadmium after the tea leaves were brewed twice with boil water in a ratio of 1g/50ml for 5min. 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 70kg individual consuming 15g of Pu-erh tea daily or 105g 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.