[Polycyclic aromatic hydrocarbons in tea and tea infusions]

Tea is the one of most widely consumed beverage in the world. It is generally believed that tea consumption might have health promoting properties. But residues of certain chemical compounds might impose a health threat on tea drinkers. The main contaminants are heavy metals, fluoride, pesticides and even dioxins. Tea lives which possess a high surface area can be contaminated with atmospheric PAHs. The manufacturing processes may also introduce PAHs into tea lives. The aim of his study was to determine the contamination of black, green, red and white teas by PAHs. In this investigation, content of 23 PAH, i.e 16 EPA PAH and 15 EU PAH were determined in 18 brands of tea and its infusions. The analytical procedure was based on ultrasonic extraction for dried tea and liquid-liquid extraction for infusions. All samples were cleaned up by florisil cartridge. The total content of 23 PAH varied between 22.9 microg/kg to 2945.5 microg/kg and 2.7 microg/kg to 63,1 microg/kg microg/kg for BaP. The analysed tea samples showed an increasing presence of PAH in the following order (mean value): black tea < red tea < green tea < white tea. However the highest content of PAH was found in the one brand of black tea bag both in sum of PAH and BaP content. During tea infusion 1.6% of total PAHs contained in tea was released into the beverage. The dominant PAHs in tea infusion were 2, 3 and 4 rings PAH, while the most toxic compounds were found at trace amounts. The concentrations of total 23 PAHs and BaP in tea infusions ranged from 332.5 ng/dm3 to 2245.9 ng/dm3 and 0.35 ng/dm3 to 18.7 ng/dm3 respectively.