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目的了解中国茶叶主产区砖茶中铅(Pb)、硒(Se)、砷(As)和汞(Hg)等元素的含量,评估长期饮用砖茶人群Pb、Se、As和Hg元素的暴露水平。方法在内蒙古、甘肃、新疆、青海、四川、西藏和云南等习惯饮用砖茶的地区收集了31份不同产区的砖茶样品,用等离子发射光谱法测定砖茶Pb含量,氢化物发生原子荧光光谱法测定砖茶中As、Se和Hg含量并进行评价。结果砖茶中Pb、Se、As及Hg的含量均值分别为6.232、0.219、0.524和0.0215 mg/kg。依据GB 2762—2012中茶叶Pb的限量标准评价,砖茶Pb超标现象较为突出,不同产地砖茶Pb含量差异明显,含量最低为云南所产沱茶和普洱茶,平均含量为1.337 mg/kg,浙江所产茯砖Pb含量亦较低,为4.303 mg/kg,符合限量标准,Pb含量最高为四川所产康砖,含量达9.998 mg/kg。所测砖茶As、Hg含量均符合NY 659—2003中规定的限量标准。采用联合国粮农组织和世界卫生组织食品添加剂联合专家委员会(JECFA)暂定的每周污染物耐受摄入量(PTWI)评价表明,长期饮用砖茶人群通过砖茶平均摄入的Pb、As和Hg对PTWI的贡献率分别为13.63%、1.71%和0.29%,均在安全范围之内;通过砖茶每日摄入的Se为0.188μg,对人群硒膳食推荐摄入量(RNI)的贡献率仅为0.38%。结论中国主要砖茶存在Pb超标现象,长期饮用砖茶人群As、Hg处于低暴露水平,饮用砖茶对补充体内Se的生理需要作用有限。
Objective To understand the content of Pb, Se, As and Hg in brick tea in the main producing areas of tea in China and evaluate the exposure of Pb, Se, As and Hg elements in long-term drinking brick tea. Methods A total of 31 samples of brick tea from different regions of China were collected in areas of Inner Mongolia, Gansu, Xinjiang, Qinghai, Sichuan, Tibet and Yunnan that were used to drink brick tea. The content of Pb in brick tea was determined by plasma emission spectrometry. The atomic fluorescence spectrometry As, Se and Hg contents in brick tea were evaluated and evaluated. Results The average contents of Pb, Se, As and Hg in brick tea were 6.232, 0.219, 0.524 and 0.0215 mg / kg, respectively. According to GB 2762-2012 in the evaluation criteria of tea leaf Pb, brick tea is more than the standard phenomenon of excessive Pb, brick tea in different areas significantly different content of Pb, Yunnan Tuo and Pu’er tea produced the lowest average content of 1.337 mg / kg produced in Zhejiang The content of Pb in Fuzhu brick is also lower, which is 4.303 mg / kg, which meets the limited standard. The highest content of Pb is Hongkang brick produced in Sichuan, with a content of 9.998 mg / kg. Measured brick tea As, Hg content are in line with NY 659-2003 in the limited standards. The provisional weekly tolerance to pollutants (PTWI) assessment using the Joint FAO / WHO Expert Committee on Food Additives (JECFA) indicated that the average intake of Pb, As and Hg by brick-tea in the long-term brick-tea drinking crowd The contribution rate of PTWI was 13.63%, 1.71% and 0.29%, respectively, which were within the safe range. The daily intake of Se was 0.188μg by brick tea, and the contribution rate to the recommended dietary intake of RN was only 0.38%. Conclusions Pb in China’s main brick tea is over-standard. As and Hg levels of brick-tea farmers who drink for a long time are at a low level of exposure. Drinking brick tea has a limited effect on the physiological needs of Se in supplementing the body.