Quantitative Determination of Heavy Metal Concentrations in Herbal Teas Marketed in Various Countries Including Libya

This study presents the determination of the amount of some heavy metals (Cu, Cr, Ni, Cd, Mn, Fe, Mg and Pb) present in commercial brand herbal tea samples purchased from local markets in Misurata, Libya, by atomic absorption spectroscopy. The validity of the analytical procedure was monitored by analysing certified reference materials obtained from the Food and Drugs Control Centre, Libya. The concentration of Cu, Cr, Ni, Cd, Mn, Fe, Mg and Pb in all the tea leaf samples ranged from 5.141 to 17.1, 0.890 to 3.4, 0.0833 to 2.349, 0.035 to 0.38, 32.01to 89.46, 79.01-167, 91.98 to 213.83 and 0.463 to 0.901 µg g-1, respectively. The concentration of heavy metals in the tea leaves can be arranged in the following order, Mg> Fe> Mn>Cu >Cr> Ni> Pb> Cd. Moreover, it is observed that the concentrations of all the toxic elements tested in the investigated herbal plants are found below the permitted levels specified by the international regulatory standards for the medicinal plants.