西藏不同居群野生穗花韭重金属含量评价

Evaluation on Heavy Metal Elements in Different Populations of Wild Milula spicata in Tibet

为明确西藏不同生境下穗花韭地上可食部分重金属含量是否超标,以32个居群的干样为材料,检测了Pb、Cr、Cd、As和Hg的含量。结果表明:除SG4居群的Pb、Cr、As和Hg含量均异常高于其他居群外,其他31个居群中的5种重金属含量普遍较低;应用系统聚类可将32个居群分为重金属综合含量高、较高、中等、较低、低5类。以鲜样计,32个居群中仅Cr和As分别有25.00%和3.13%的超标率,SG4居群中Cr和As的超标倍数分别为3.84和0.70,SG1、ZB2、NML1、SZZ1、RB1、DL2和SR1居群中Cr的超标倍数为0.01~1.22;以综合污染指数分级时,SG4居群为重度污染等级,SG1、ZB2、RB1、SR1为轻度污染等级,NML1、SZZ1、DL2为警戒等级,其他居群为安全等级。以干样计,Cd未超标,Pb、Cr、As和Hg的超标率分别为59.38%、84.38%、34.38%和84.38%,在各居群中,Pb、Cr、As和Hg的超标倍数分别为0.02~4.39、0.05~31.26、0.03~10.36和0.04~1.48,SG4居群的Pb、Cr、As超标倍数最高,分别达到4.39、31.26、10.36倍;以综合污染指数分级时,除ZN1、NML2为警戒等级外,其他居群均为轻度到重度污染等级。综合来看,SG4居群重金属元素超标严重不宜食用,其他居群鲜食时重金属元素影响不大,但因民间食用以干品为主,故在食用干品时以每次少量为宜。

In order to definit whether the heavy metal contents in overground edible part of Milula spicata under different ecological environment in Tibet is exceeded standard,this experiment took 32 dry samples from 32 populations as test material;and detected the contents of Pb,Cr,Cd,As and Hg.The results showed that the contents of Pb,Cr,As and Hg in SG4 population were significantly higher than those in the other populations,the contents of 5 heavy metals in the other 31 populations were generally lower.The 32 populations could be divided into 5 groups with different heavy metal contents by systematic clustering:high,higher,medium,lower,low.Caculating in terms of fresh samples,among 32 populations,only Cr and As had 25.00%and 3.13%over standard rates,respectively.Among SG4 population,the times of ultra standard of Cr and As were 3.84 and 0.70,respectively.The times of ultra standard of Cr in SG1,ZB2,NML1,SZZ1,RB1,DL2 and SR1 populations were 0.01-1.22.Grading in terms of comprehensive pollution index,SG4 population was classified as heavy pollution;SG1,ZB2,RB1 and SR1 as mild pollution;NML1,SZZ1 and DL2 as alert class;the other populations as safe class.Caculating in terms of dry samples,Cd did not exceed the standard,while the over standard rates of Pb,Cr,As and Hg were 59.38%,84.38%,34.38% and 84.38%,respectively.In each population,times of ultra standard of Pb,Cr,As and Hg were 0.02-4.39,0.05-31.26,0.03-10.36 and 0.04-1.48,respectively.In SG4 population,times of ultra standard of Pb,Cr and As were the highest,reaching 4.39,31.26 and 10.36,respectively.Grading in terms of comprehensive pollution index,except ZN1 and NML2 were alert class,the other populations were all mild to heavy pollution class.In general,the heavy metal elements in SG4 population exceeded the standard seriously and were inedible.The heavy metal elements in the other populations had little effect on fresh-eating.Because the local people mainly eat dried food,taking a small amount of dry one each time is advisable.