Assessment of the Quality of Herbal Teas from Šabac, Serbia in Terms of the Content of Heavy Metals

Abstract

Chemical components of teas have received great interest because they are related to health. In this work, data on the determination of foreign matter, loss on drying/water content, total ash and ash insoluble in hydrochloric acid are presented. The content of seven heavy metals including Cu, Fe, Mn, Zn, Ni, Cd and Pb were determined by atomic absorption spectrometry in samples of several herbal teas: Matricariae flos, Thymi herba, Menthae piperitae folium, Betulae folium, Quercus cortex, Gentianae radix, Frangulae cortex, Althaeae radix, Uvae ursi folium and Glycyrrhizae radix collected from Šabac’s market, Serbia. The sample preparation procedure involved dry digestion and dissolution of the ash in 6M HCl and then in 0.1 M HNO3. Herbal teas showed the concentration of heavy metals Cu, Fe, Mn, Zn and Ni in the range: 2.9 ± 0.1 – 22.2 ± 0.9 mg/kg, 118.5 ± 1.1 – 755.5 ± 2.5 mg/kg, 19.0 ± 5.8 – 561.0 ± 1.9 mg/kg, 6.5 ± 0.4 – 242.5 ± 1.4 mg/kg and 2.5 ± 0.1 – 10 ± 1.1 mg/kg, respectively. The level of copper in all samples was uniform. The highest content of Fe was in Thymi herba, while Mn and Zn were at maximum in Betulae folium. The levels of toxic heavy metals Cd and Pb were below the detection limit. The obtained values were compared with data available from literature. The herbal tea samples analyzed contained essential heavy metals (Cu, Fe, Mn, Zn) and probably essential in trace (Ni), and could obey the daily dietary requirements. Noncancer health risk assessment detected that the herbal teas of Betulae folium and Frangulae cortex can manifest some health risk to consumers.