绍兴地区市售茶叶及代用茶中有害元素含量调查

目的 测定绍兴地区市售茶叶及代用茶中Pb、Cd、Ni、Cr、Hg、As和Al共7种有害元素的含量,并对污染水平进行分析。 方法 2016-2017年随机采集绍兴地区的商店、农贸市场等地的茶叶样品85份(其中绿茶58份,红茶11份,青茶12份,黑茶4份),代用茶样品158份(其中大麦茶48份,花茶73份,苦丁茶37份),采用微波消解-电感耦合等离子体质谱法测定样品中7种元素的含量,按GB 2762-2017《食品安全国家标准 食品中污染物限量》和NY 659-2003《茶叶中铬、镉、汞、砷及氟化物限量》评价检测结果。 结果 四种茶叶中Pb、Cd、Hg和As的含量差异均无统计学意义(P>0.05);Ni、Cr和Al含量最高的茶叶分别是绿茶、黑茶和青茶,中位数分别为5.59、0.70和1 265 mg/kg;绿茶、红茶和青茶中As的超标率分别为20.69%、18.18%和16.67%。苦丁茶中Cd、Ni和Al均为代用茶中最高,中位数分别为0.93、1.72和158 mg/kg;花茶中Pb和Cr均为代用茶中最高,中位数分别为0.31和0.19 mg/kg;大麦茶、花茶和苦丁茶中砷的超标率分别为2.08%、4.11%和2.70%;大麦茶和苦丁茶中Pb超标率分别为14.60%和2.70%;苦丁茶中Cd超标率为43.24%,最大值23.7 mg/kg。 结论 绍兴地区市售茶叶中As及苦丁茶中Cd污染情况需引起重视,建议继续加强监测力度,寻找污染来源并采取适当的控制措施。

Contents of harmful elements in tea and tea substitutes sold in the markets in Shaoxing region

Objective To investigate the contents of seven harmful elements (including Pb, Cd, Ni, Cr, Hg, As and Al) in tea and tea substitutes sold in the markets in Shaoxing region, and to analyze their pollution levels. Methods We randomly collected 85 tea samples (including 58 green tea samples, 11 black tea samples, 12 oolong tea samples and 4 Puer tea samples) and 158 tea substitutes (including 48 barley tea samples, 73 flower tea samples and 37 broadleaf holly leaf tea samples) from shops and farmers’ markets in Shaoxing region. The contents of seven harmful elements were determined by inductively coupled plasma mass spectrometry with microwave digestion, and then the Results were evaluated according to China Food Safety National Standard for Maximum Levels of Contaminants in Foods (GB 2762-2017) and the Limited Standards of Cr , Cd , Hg , As and F in Tea (NY 659-2003). Results No statistically significant differences were found in the contents of Pb, Cd, Hg and As among the four kinds of tea (P>0.05). The contents of Ni, Cr and Al were found to be respectively the highest in green tea, Puer tea and oolong tea samples, and the medians were 5.59, 0.70 and 1,265 mg/kg respectively. The exceeding standard rates of As in green tea, black tea and oolong tea samples were 20.69%, 18.18% and 16.67% respectively. The contents of Cd, Ni and Al in broadleaf holly leaf tea were the highest in tea substitutes, with the medians of 0.93, 1.72 and 158 mg/kg respectively. The contents of Pb and Cr in flower tea were the highest in tea substitutes, with the medians of 0.31 and 0.19 mg/kg respectively. The exceeding standard rates of As in barley tea, flower tea and broadleaf holly leaf tea were 2.08%, 4.11% and 2.70% respectively. The exceeding standard rates of Pb in barley tea and broadleaf holly leaf tea were 14.60% and 2.70% respectively. The exceeding standard rate of Cd in broadleaf holly leaf tea was 43.2%, with the maximum value being 23.7 mg/kg. Conclusions Special attention should be paid to the pollution of As in tea and Cd in broadleaf holly leaf tea sold in the markets in Shaoxing region. It is necessary to continuously enhance monitoring and find sources of pollution so as to take appropriate control measures.