Lead and Copper Levels in Tea Samples Marketed in Beijing, China

Abstract

Next to water, tea is the most widely consumed beverage (Marcos et al., 1998) because of its taste aroma and health benefits. On the basis of extensive animal experiments and some epidemiologic data, tea is considered to have numerous beneficial effects on the prevention of many diseases, including skin cancer (Katharine, 2001), Parkinson’s disease (Richard, 2001), myocardial infarction (Cheng, 2003), and coronary artery disease (Hirano et al., 2003). Tea is produced from the leaves of the tropical evergreen Camellia sinensis, which is indigenous to China. In China, tea sipping is an integral part of the culture. In the world, China is a major tea producer, supplying 23.3% of the world’s tea. However, the rapid industrialization of China over the past two decades has caused increased contamination to the environment, which inevitably has brought contamination to tea. During the growth period of the tea plant and during tea processing, tea itself can be contaminated by heavy metals, such as lead and copper, which might increase the metal body burden in humans. Lead is a physiologic and neurologic toxin that can affect almost every organ and system in the human body. It can reduce cognitive development and intellectual performance in children and damage kidneys and the reproductive system. Copper is an essential element, with both deficiencies and excesses associated with impaired health. Copper deficiency is known to cause various physiologic disorders such as anemia and bone abnormalities (Uauy et al., 1998) resulting from decreased activity of the copper-requiring enzymes. Copper excess can cause hepatic and kidney damage, hemolytic anemia (Evans, 1973), and methaemoglobinemia (Chugh et al., 1975). Therefore, after the pesticide contamination issue, heavy metal contamination in teas has become another noteworthy issue because it is related directly to heath and disease. The current study aimed to determine the lead and copper concentrations in tea samples collected from the Beijing market, and to give an overview of the current safety situation of teas marketed in Beijing, host of the Olympic Games in the year 2008.