Li Lanhai, Fu Qing-Long, Achal Varenyam, Liu Yonglin
College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China.
Environ Monit Assess. 2015 May;187(5):228. doi: 10.1007/s10661-015-4445-2. Epub 2015 Apr 4.
Heavy metals and Al in tea products are of increasing concern. In this study, contents of Al, Cd, Co, Cr, Cu, Ni, and Pb in commercially available green tea and its infusions were measured by ICP-MS and ICP-AES. Both target hazard quotient (THQ) and hazard index (HI) were employed to assess the potential health risk of studied metals in tea leaves and infusions to drinkers. Results showed that the average contents of Al, Cd, Co, Cr, Cu, Ni, and Pb in tea leaves were 487.57, 0.055, 0.29, 1.63, 17.04, 7.71, and 0.92 mg/kg, respectively. Except for Cu, metal contents were within their maximum limits (1, 5, 30, and 5 mg/kg for Cd, Cr, Cu, and Pb, respectively) of current standards for tea products. Concentrations of metals in tea infusions were all below their maximum limits (0.2, 0.005, 0.05, 1.0, 0.02, and 0.01 mg/L for Al, Cd, Cr(VI), Cu, Ni, and Pb, respectively) for drinking water, and decreased with the increase of infusion times. Pb, Cd, Cu, and Al mainly remained in tea leaves. The THQ from 2.33 × 10(-5) to 1.47 × 10(-1) and HI from1.41 × 10(-2) to 3.45 × 10(-1) values in tea infusions were all less than 1, suggesting that consumption of tea infusions would not cause significant health risks for consumers. More attention should be paid to monitor Co content in green tea. Both THQ and HI values decreased with the increase of infusion times. Results of this study suggest that tea drinkers should discard the first tea infusion and drink the following infusions.
茶产品中的重金属和铝越来越受到关注。在本研究中，采用电感耦合等离子体质谱法（ICP-MS）和电感耦合等离子体发射光谱法（ICP-AES）测定了市售绿茶及其茶汤中铝、镉、钴、铬、铜、镍和铅的含量。采用目标危害商数（THQ）和危害指数（HI）评估茶叶及其茶汤中所研究金属对饮用者的潜在健康风险。结果表明，茶叶中铝、镉、钴、铬、铜、镍和铅的平均含量分别为487.57、0.055、0.29、1.63、17.04、7.71和0.92mg/kg。除铜外，其他金属含量均在现行茶产品标准的最大限量范围内（镉、铬、铜和铅的最大限量分别为1、5、30和5mg/kg）。茶汤中金属浓度均低于饮用水的最大限量（铝、镉、六价铬、铜、镍和铅的最大限量分别为0.2、0.005、0.05、1.0、0.02和0.01mg/L），且随冲泡次数的增加而降低。铅、镉、铜和铝主要残留在茶叶中。茶汤中THQ值在2.33×10⁻⁵至1.47×10⁻¹之间，HI值在1.41×10⁻²至3.45×10⁻¹之间，均小于1，表明饮用茶汤不会对消费者造成显著健康风险。应更加关注绿茶中钴含量的监测。THQ和HI值均随冲泡次数的增加而降低。本研究结果表明，饮茶者应倒掉第一泡茶水，饮用后续冲泡的茶水。
