Accumulation of potentially toxic elements in Chinese tea (Camellia sinensis): Towards source apportionment and health risk assessment

Abstract

Tea (Camellia sinensis) is a popular beverage that is consumed globally. However, a better understanding of potentially toxic elements (PTEs) content in tea leaves and infusion is necessary to minimize risk on human health. Therefore, 249 tea samples (grown in different areas) covering six types of tea were collected in China to investigate the PTEs contents, identify their potential source and assess the health risk associated with drinking tea. PTE contents in tea leaves across six tea types were ND–0.900 (Cd), 0.005–2.133 (As), ND–5.679 (Pb), ND–13.86 (Cr), 1.601–22.93 (Ni), ND–2.048 (Se), 0.109–622.4 (F), 13.02–269.9 (Rb), 1.845–50.88 (Sr), and 2.796–53.23 (Ba) mg/kg. The result of tea infusion showed that 14.3 %–44.1 % (green tea), 14.5 %–46.7 % (black tea), 10.5 %–25.3 % (dark tea), 13.6 %–34.2 % (oolong tea), 16.9 %–40.7 % (yellow tea), and 19.9 %–35.1 % (white tea) of F were released. All tea types, except green tea, exhibited comparatively low leachability of Cd, As, Pb and Cr in tea infusion. The source apportionment revealed that PTEs in tea leaves mainly originated from soil parental materials, while industrial activities, fertilizer application, and manufacturing processes may contribute to exogenous Se, Cd, As, and Cr accumulation. Health risk assessment indicated that F in tea infusion dominated the health risk. Humans may be exposed to a higher health risk by drinking green tea compared to that of other tea types. Nevertheless, the long-term tea consumption is less likely to contribute to pronounced non-carcinogenic and carcinogenic risks. This study confirmed that tea consumption is an important and direct pathway of PTEs uptake in humans. The health risk associated with drinking tea should be of concern.