辽阳市土壤重金属含量特征及潜在风险评价

Characteristics and potential risk assessment of heavy metal contents in urban soil,Liaoyang City

采用污染负荷指数法和生态危害指数法对辽阳城市表层土壤样品中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn等重金属元素的污染程度及其生态风险进行评价。结果表明,土壤As元素基本无污染,其他7项重金属元素含量均高于对应的全国土壤背景值,其中Hg、Cd为主要污染元素,其污染程度分别为重度、中度,Zn、Pb、Cu、Cr、Ni元素处于轻度污染。生态风险评价结果显示,Hg、Cd亦为主要生态风险因子,Hg属于较强生态风险,Cd属于中等生态风险。辽阳城区存在轻度重金属元素污染,潜在生态风险水平为中等;新城区土壤生态环境优于老城区,建议进一步发挥新城疏导功能,缓解城市压力。

The contents and pollution degree of As,Cd,Cr,Cu,Hg,Ni,Pb,Zn and other elements in surface soil samples of Liaoyang urban greenbelt were comprehensively analyzed by pollution load index method and ecological risk index method.The results show that,except As,the concentrations of other seven heavy metal elements in soil is higher than the national background value,of which Hg,Cd are the main pollution elements,and the degree of their contamination has reached heavy and moderate respectively.The trace elements of Zn,Pb,Cu,Cr and Ni are in slight pollution,while As is basically free of contamination.The evaluation of the ecological risk shows that Hg and Cd elements are the main ecological risk factors,and Hg and Cd belong to strong and medium ecological risk respectively.In general,Liaoyang City has slight heavy metal element pollution with medium potential ecological risk.The soil ecological environment in the new city is better than that in the old one,and it is recommended to further play the role of dredging function of the new city to relieve the urban pressure.