冬虫夏草及产区土壤中5种重金属及有害元素污染评价

Pollution assessment of five heavy metals and harmful element in Cordyceps and its habitat's soil

目的:建立冬虫夏草及产区土壤中重金属及有害元素残留量的测定方法,并对污染水平进行评价。方法:采用电感耦合等离子体质谱(ICP-MS)法测定不同产地冬虫夏草及周围土壤中铅(Pb)、镉(Cd)、砷(As)、汞(Hg)、铜(Cu)的含量。射频功率为1 550 W,载气(高纯氩气)流速为1.05 L·min^(-1),等离子气体流速为15.0 L·min^(-1),蠕动泵转速0.2 r·s^(-1),采样深度8 mm,积分时间为0.1 s。通过在线加入内标锗(Ge)、铟(In)、铋(Bi)元素的方法来校正基体效应和干扰。结果:冬虫夏草及土壤中5种重金属及有害元素的线性关系良好(r>0.99),回收率为80%～120%。采用单项污染指数法和内梅罗综合污染指数法对药材及产区土壤进行评价。根据GB15618-1995土壤环境质量标准一级规定,冬虫夏草产区土壤中5种重金属及有害元素平均单项污染指数由大至小顺序为Cd、As、Pb、Hg、Cu,其中Cd、As、Pb是主要的重金属及有害元素污染物,而Hg和Cu则基本不存在污染情况,8批土壤As、Cd、Pb存在超标的情况,其不合格率分别为88%、50%、25%;根据现行《中华人民共和国药典》2015年版植物药重金属及有害元素的限量标准,冬虫夏草药材5种重金属及有害元素平均单项污染指数由大至小顺序为As、Cu、Cd、Pb、Hg,其中As是主要的药材有害元素污染物,而Cu、Cd、Hg和Pb则不存在污染情况,5批次虫草As不合格率为100%;同时考察冬虫夏草不同部位As污染情况,发现As含量大部分集中在虫体,子座较少。结论:冬虫夏草及产区土壤中总砷含量水平较高,因此冬虫夏草总砷含量较高可能与其专属性富集砷特性密切相关;其他元素含量水平较低。

Objective:To establish a method for the determination of heavy metals and harmful element in Cordyceps and and its habitat’s soil,and to evaluate the level of contamination.Methods:The contents of Pb,Cd,As,Hg and Cu in Cordyceps and the surrounding soil from different habitats were determined by ICP-MS.The RF power was 1 550 W and the flow rate of carrier gas was 1.05 L·min-1.Plasma gas flow rate was 15.0 L·min-1.Peristaltic pump speed was 0.2 r·s-1 and the sampling depth was 8 mm.The integration time was 0.1 s.The realtime injection of internal standard solution with Ge,In and Bi was used to help calibration of matrix effects and interference.Results:5 heavy metals and harmful element in Cordyceps and soil showed good linear relationship(r>0.99),and the recovery rates were in the range of 80%to 120%.The result was evaluated by using the method of single factor pollution index and comprehensive pollution index.According to degreeⅠlimit of the standard for soil environment(GB15618-1995),the average single pollution index order of 5 heavy metals and harmful element in producing soil was Cd>As>Pb>Hg>Cu,with Cd,As and Pb as the major contaminants.And there was almost no contamination of Hg or Cu.As,Cd and Pb in 8 batches of soil exceed the limits with failure rates of 88%,50%and 25%separately.According to the limits of heavy metals and harmful elements in herbal medicine(Chinese Pharmacopoeia,2015 edition),the average single pollution index order of 5 elements in medicinal Cordyceps was As>Cu>Cd>Pb>Hg,where As was the main contaminant.And there was almost no contamination of Cu,Cd,Hg and Pb.The failure rates of As in 5 batches of Cordyceps were 100%.At the same time,As pollution in different parts of Cordyceps was investigated.The result indicated that As was abundant in the parasites,but less in the sub-seat.Conclusion:The residue of total arsenic in Cordyceps and its habitat’s soil was high.Total arsenic contamination in Cordyceps may be closely related to its enrichment characteristics.Residues of other elements were low in Cordyceps.