喀什市蔬菜基地土壤重金属含量及其生态风险评价

Heavy Metal Contents and Ecological Risk Assessment of the Vegetable Base Soils in Kashgar City

为更好地预防无公害蔬菜基地重金属污染,采集了喀什市蔬菜基地表层土壤样品,重点对疏勒县、五里桥、远方市场和四十二团等四处蔬菜基地土壤中Cu、Cr、Pb、Zn等4种重金属含量进行了测定和分析。采用了单因子污染指数法、综合污染指数法和潜在生态风险系数法对其污染状况进行评价。结果表明:喀什市这4个主要的蔬菜基地土壤环境质量处于清洁水平,所测定的土壤重金属Cu元素含量超标,土壤受到轻度污染。土壤中各金属潜在风险系数按平均值大小依次是Cu>Cr>Pb>Zn。土壤中重金属Cu的变异程度比其它金属元素大,达到中等程度的变异。综合潜在生态风险系数(RI)也表明这4个蔬菜基地土壤属于轻度危害。

In order to prevent the pollution by havy metal of vegetable base, the contents of heavy metals in surface soil samples were collected in vegetable base in Kashgar city. There were four vegetable bases were considered including Sbule connty, Wuliqiao, Yuanfang Market and Sishiertuan. Four heavy mental such as Cu, Cr, Pb,Zn and the contamination of heavy metals in soils was assessed with single-factor pollution index method, Nemerow comprehensive pollution index method and potential ecological harm index method. The results indicated that all vegetable base soil environmental quality were clean level whereas heavy metals Cu content over standard. Soil were slight pollution by metal Cu. The rank of average Nemerow comprehensive pollution index of four heavy metals in the vegetable base soil was Cu〉Cr〉Pb〉Zn. The coefficient of variation （CV） of the metal Cu was higher than others which means belonged to intermediate variation. Comprehensive potential ecological harm index showed that the four vegetable base soil were in slight harm degree.