太原市土壤重金属分布特征及生态风险评价

Distribution Characteristics and Ecological Risk Assessment of Heavy Metals in Soil of Taiyuan City

对太原市周边地区进行土壤样品采集,并测定了土壤样品中5种重金属(Cr、Cd、Pb、As和Hg)的含量,利用统计学方法、半方差函数和地理信息技术(ArcGIS)分析了5种重金属在研究区的分布特征,并利用内梅罗综合污染指数评价研究区的污染现状。结果显示,5种重金属在研究区均表现为不同程度的污染,均值都大于山西省土壤背景值,其中,Cd的均值甚至大于国家土壤质量二级标准;半方差函数分析结果表明,Cr、Cd、Pb和Hg在研究区的累积受一定程度人为活动的影响,而As则主要受自然因素的影响;研究区西南部为Cr、Cd、Pb和Hg的主要富集地区,研究区北部则是Cr的主要富集地区;污染评价结果表明,研究区污染情况较为严重,已达到重度污染,主要贡献因子为Hg元素。

The soil samples were collected from the surrounding areas of Taiyuan city and the contents of heavy metals such as Cr,Cd,Pb,As and Hg were measured.Five heavy metals were analyzed by statistical methods,semi-variance function and geographic information method(ArcGIS).The distribution characteristics of the area and the pollution status of the study area were evaluated by the Nemero comprehensive pollution index.The results showed that the five heavy metals Cr,Cd,Pb,As and Hg showed different degrees of pollution in the study area,which the mean values were larger than the soil background values of Shanxi province.The average value of Cd was even greater than the national soil quality secondary standard.The functional analysis showed that the accumulation of Cr,Cd,Pb and Hg in the study area was affected by a certain degree of human activities,while As was mainly affected by natural factors.The distribution of heavy metals indicated that Cr,Cd,Pb and Hg were in the southwest of the study area,Cr was in the north of the study area.The pollution assessment results showed that the pollution status of the study area was serious and reached severe pollution.The main contribution factor was Hg.