夏尔西里自然保护区土壤重金属空间分布特征及其评价

Spatial Distribution Characteristic and Evaluation of Soil Heavy Metals in Xarxili Natural Reserve

土壤重金属空间变异性是监测和评价土壤生态系统环境质量的前提。本文采用多元统计和地统计相结合的方法,对位于夏尔西里地区的山地森林、绿洲、半荒漠、荒漠土壤中Hg、As、Cd、Cr、Pb、Mn、Cu、Zn、Ni等9种土壤重金属元素的空间变异结构和分布格局进行了分析,评价了土壤重金属的污染程度,旨在为土壤重金属污染提供理论依据。结果表明:重金属Co、Cr、Cu、Mn、Ni、Pb、Zn、Hg、As平均含量分别为13.44、66.07、45.86、695.45、26.02、50.74、112.36、0.39、78.09,重金属Co、Ni平均含量未超过新疆土壤背景值,Cr、Cu、Mn、Pb、Zn、Hg和As的平均含量均超过新疆土壤背景值,超标分别为1.33、1.67、1.04、2.67、1.67、24.97、6.79。综合污染指数评价表明:夏尔西里4个采样区表层土壤中9种重金属的综合污染指数均大于3,表明综合污染值为重度污染水平。Hg和As是危害最严重的2种金属,对夏尔西里整个区域的土壤重金属潜在生态危害污染贡献较为突出。

Heavy metal pollution in fields has become an important frontier in environmental research and drawn more and more attentions,Xarxili area is located in the southern piedmont of the Alatao Mountain in Xinjiang.Aim of the study is to control soil heavy metal pollution and provide the basic information,the single pollution index and the composite pollution index were used to evaluate the soil heavy metal pollution.During 2014-2015,a total of 317 topsoil samples were collected from these regions,which included mountain forest,semi-desert,desert and oasis area.The results showed that the average concentrations of the Co,Cr,Cu,Mn,Ni,Pb,Zn,Hg,As were 13.44、66.07、45.86、695.45、26.02、50.74、112.36、0.39、78.09 mg·kg-1,respectively.The average content of Co and Ni of heavy metals did not exceed the background values of Xinjiang.The average contents of Cr,Cu,Mn,Pb,Zn,Hg and As all exceeded the background values of Xinjiang.The over standard were 1.33,1.67,1.04,2.67,1.67,24.97,6.79,respectively.The comprehensive pollution index evaluation showed that the comprehensive pollution index of the 9 heavy metals in the surface soil of Xarxili's 4 sampling areas was greater than 3,indicating that the comprehensive pollution value is a severe pollution level.Hg and As are the 2 kinds of metals which are most endanger,and contribute more to the potential ecological pollution of soil heavy metals in the whole area of Xarxili.