陕西某冶炼区农田土壤重金属污染特征

摘要

Taking farmland vegetable soil of a smelting area in Shaanxi as the research object,with the single factor pollution,the index method pollution,the pollution load index and the potential ecological risk index,we evaluted the pollution condition of farmland vegetables soil of the heavy metal with Cu,Ni,Mn and Cd in a smelting area. The results showed that with the single factor pollution,nine kinds of vegetables of lettuce,parsley,artemisia stelleriana,small greens,lettuces,spinach,shallot,leek,and garlic sprout soils of heavy metal with Cu,Ni and Mn contents were security,and the heavy metal Cd contents were badly exceeded the standard. Five kinds of vegetables of brassica chinensis,spinage,green chinese onion,fragrant-flowered garlic,and garlic sprout soils of heavy metal zinc contents were exceeded,and the over standard rate was 55.56%. With the index method pollution,nine kinds of vegetables soil were seriously polluted by heavy metals. With the pollution load index ,heavy metals of spinage and leek were moderate pollution. Moreover,the heavy metal soil contents of other vegetables were safe. With the potential ecological risk index,the ecological rick index of heavy metal in nine kinds of vegetables was 88.89%, which belonged to the medium and strong ecological risk. Especially,the ecological harm of heavy metal Cd was higher. With the correlation analysis and the principal component analysis,we found the soils of the heavy metal with Zn and Mn or Zn and Cd or Ni and Mn in smelting area vegetables were high significant positive correlation ,but between the other heavy metals were no significant difference. The vegetables farmland soils of heavy metal pollution in the smelting area could be compound the pollution sources.%以陕西某冶炼区农田蔬菜地土壤为研究对象,采用单因子污染指数法、污染负荷指数法、综合污染指数法和潜在生态风险指数法评价冶炼区农田蔬菜地土壤重金属Zn、Cu、Ni、Mn、Cd的污染状况.结果表明,单项污染评价生菜、香菜、白蒿、小青菜、油麦菜、菠菜、大葱、韭菜、蒜苗地土壤重金属Cu、Ni、Mn含量是安全的,重金属Cd含量严重超标,而小青菜、菠菜、大葱、韭菜、蒜苗这5种蔬菜地土壤Zn含量超标,超标率为55.56%.综合污染评价9种蔬菜地土壤均被重金属严重污染,污染负荷评价菠菜和韭菜地重金属为中度污染,其他蔬菜地土壤重金属含量符合标准.9种蔬菜地土壤中重金属的生态危害指数88.89%,属于中等及极强生态风险,尤其Cd的生态危害较高.相关性分析与主成分分析冶炼区蔬菜地土壤中Zn与Mn、Zn与Cd、Ni与Mn均呈现出极显著正相关(P<0.01),而其他重金属之间均呈现出不显著性差异(P>0.05),说明冶炼区农田蔬菜地土壤重金属的污染可能是复合污染源造成的.