Science Alert
Pakistan Journal of Biological Sciences
  Year: 2003 | Volume: 6 | Issue: 3 | Page No.: 208-212
DOI: 10.3923/pjbs.2003.208.212
Heavy Metal Contents in Tea and Herb Leaves
Saud S. AL-Oud

The quality of tea brands and herbs available in the retail market in the Kingdom of Saudi Arabia were assessed based on contents of heavy metals in their tissues. All tested brands of tea and herbs possess considerable amounts of the eight tested heavy metals, Mn, Fe, Zn, Cu, Ni, Co, Pb and Cd. The tested nine brands of tea as well as five herbs proved high variability (P < 0.01) in their contents of heavy metals. Among tested heavy metals, Mn was the most abundant one in tea leaves (390-900 μg g–1) whereas Fe was the predominance one in herb leaves (326-1755 μg g–1). Fortunately, toxic heavy metals, Pb and Cd, had the lowest contents in both tea and herb leaves. Among tested tea brands, Chinese green tea possesses the highest contents of heavy metals. Concentrations of tested heavy metals in tea and herb beverage were markedly lower than their total contents. The concentrations of toxic heavy metals, Pb and Cd were too low to be detected in beverage using the available analytical techniques. The solubility of studied heavy metals in both brew and infusion extracts varied widely and ranged from 0.0-48%. The lowest rates of solubility were listed for toxic heavy metals Pb and Cd. The amounts of heavy metals that one may take up through consumption of tea and herb beverages were found to match the acceptable daily intake that takes into account exposure from air, food and drinking water.
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06 September, 2014
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heavy metal in herbal tea

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