Polycyclic aromatic hydrocarbons in commercial tea from China and implications for human exposure

Abstract

Tea consumption may increase the level of human exposure to polycyclic aromatic hydrocarbons (PAHs), while relevant health risks are unclear. This study collected 218 samples of five categories of tea (dark, green, black, oolong, and white) from seven major tea sources in China. High performance liquid chromatography was used to determine the concentrations of 16 common PAHs. The concentration of all 16 PAHs (ΣPAHs) varied from 11.4 to 1251 ng/g, with a median value of 86.4 ng/g. Of the five tea categories from the seven source provinces, the median ΣPAHs concentration values were ordered as 189 ng/g (dark tea) > 110 ng/g (oolong tea) > 83.3 ng/g (green tea) > 49.7 ng/g (black tea) > 33.7 ng/g (white tea). Dark tea from Hunan had the highest level of PAHs, and white tea was the least contaminated with PAHs. The 3-ring PAHs and 4-ring PAHs were dominant in tea. The sources of PAHs in tea were mainly attributed to grass, wood, and coal combustion. The median margin of exposure (MOE) and incremental lifetime cancer risk (ILCR) values of benzo(a)pyrene (BaP) were 4.22E+ 04 and 6.86E-06 (dark tea), 8.14E+ 04 and 3.55E-06 (green tea), 1.71E+ 05 and 1.69E-06 (black tea), 4.97E+ 04 and 5.88E-06 (oolong tea), 7.42E+ 05 and 3.89E-07 (white tea), respectively. The results showed that chronic exposure to PAHs via the consumption of dark, oolong, black, and green tea, can result in a carcinogenic risk to humans, which should be a public health concern.