Essential and toxic metals in tea (Camellia sinensis) imported and produced in Ethiopia

Abstract

Sixteen  samples of packed tea leaves (Camellia sinensis) were purchased from supermarkets in Addis Ababa, Ethiopia for metal analysis. Elements were measured by FAAS and graphite furnace atomic absorption spectrometer (GFAAS) employing external calibration curves. The levels in mg/kg dried weight basis varied from Cu: 4.7–12.9; Cd: 0.02–2.83; Pb: <0.01–2.29; Zn: 8.6–198.3; Mn: 81.7–962.2; Al: 3376.4–10,369.3; K: 7667.7–10,775; Li: 0.2–0.62; Ba: 9.4–1407.1; Mg: 1145.6–1834.1; Fe: 286.4–880.9; Ca: 1414.2–2646.0; Na: 147.1–557.7. Levels of exposure to the investigated metals by drinking tea were checked with the recommended daily allowance (RDA) of the WHO/FAO. Considering the average daily consumption rate of tea alone, the possible daily intakes of Al, Ba and Mn surpass the amenability to the side effects associated with these elements like Alzheimer’s disease, kidney damage and Parkinson’s disease, respectively, for which drinking tea should cause awareness. The other investigated elements are in the acceptable range.

Keywords:

• tea
• Camellia sinensis
• metals
• Flame Atomic Absorption/Emission Spectrometer (FAAS)
• graphite furnace atomic absorption spectrometer (GFAAS)
• Ethiopia

Acknowledgements

The author is grateful to EPHARM S.C. for permission to use FAAS equipment and the Department of Earth Sciences, Addis Ababa University for giving access to the GFAAS instrument. Addis Ababa University funded this research.