Polycyclic Aromatic Hydrocarbon Contamination in Three Tea Samples Collected in Two Different Areas of Vietnam

Abstract

The present work was undertaken to identify and determine the concentration of PAHs in forty samples of three different types of tea (green, oolong and black teas) collected in two provinces of Vietnam (Thai Nguyen province in the North and Lam Dong province in the South). For sample preparation, the quick and simple QuEChRES procedure was used and eighteen PAHs congeners were detected by gas chromatography–tandem mass spectrometry (GC-MS/MS), with the percentage recovery higher than 70%. The concentration of the total 18 PAHs in tea samples ranged from 154.2 to 709.0 μg/kg with the highest of total PAHs found in black tea samples. Nine PAHs congeners were found in all samples with wide ranges of concentrations as follows: 1-methylnapththalene (3.6 – 73.1 μg/kg), Acenaphthene (1.6 – 45.0 μg/kg), Fluorene (4.2 – 49.5 μg/kg), Anthracene (2.1 – 40.0 μg/kg), Pyrene (19.3 – 224.9 μg/kg), Chrysene (4.6 – 233.0 μg/kg), Benzo (b) fluoranthene (0.6 – 23.7 μg/kg), Indeno (1,2,3,cd) pyrene (1.0 – 38.4 μg/kg), and Dibenzo (a,h) anthraxcene (1.1 – 25.0 μg/kg). 3–4 rings PAHs were dominant in all tea samples, with a contribution of 66.0 – 84.3% of the total 18 PAHs content. The average content of the indicated PAHs in oolong tea from the South (OS) was the lowest and that of black tea from the South (BS) was the highest. It was also observed that the toxic equivalent (TEQ) values of tea samples from the North higher than those from the South.