大连市农地土壤重金属污染及潜在风险评价

Farmland heavy metal pollution and its potential ecological risk Dalian

我国的耕地土壤重金属污染越来越严重,进行区域土壤重金属污染评价对于制定土壤重金属污染防治政策具有重要意义.旨在探究大连市典型农地土壤重金属污染状况,调查大连市农地表层土壤中的镍(Ni)、铬(Cr)、锌(Zn)、铜(Cu)、铅(Pb)、汞(Hg)和锰(Mn)7种重金属元素的含量,并定量评价研究区土壤重金属污染水平.研究选择大连市典型农地样地,等间距采集土壤表层样品,采用单因子指数法、内梅罗指数法和潜在生态风险指数法对研究区土壤样品进行污染状况评价和环境风险评价,以期为大连市农地土壤重金属污染的有效防治和农产品的安全健康生产提供科学依据.结果显示:①土壤样品中镍(Ni)、铬(Cr)、锌(Zn)、铜(Cu)、铅(Pb)的元素含量平均值分别为84.74、156.56、89.71、46.74和53.23mg/kg,均符合《土壤环境质量标准》(GB15618—1995)二级标准;②Hg的变异系数>0.5,污染源为点源污染,推测为人类活动导致;③单因子指数法表明Ni的富集作用最为严重,结合研究区实际情况推测其来源为人为源.内梅罗指数表明大连市土壤存在轻度污染.潜在生态风险指数表明大连市农地土壤存在轻微危害.④大连市农地土壤污染状况相对较轻,土壤质量总体水平较高,但仍需要采取相关措施防止重金属的富集,减少重金属对大连市农地土壤的负面影响.

The heavy metal pollution of farmland soil is becoming more and more serious in China,so it is of great significance to evaluate the regional heavy metal pollution in the soil heavy metal pollution.This study investigates the situation of heavy metal pollution in the typical agricultural soil in Dalian by examining seven heavy metal elements including nickel(Ni),chromium(Cr),zinc(Zn),copper(Cu),lead(Pb),mercury(Hg)and manganese(Mn)in the surface soil of farmland.The heavy metal pollution level in the soil in the study area was quantitatively evaluated.Select typical farmland plots in Dalian,sample soil surface samples at equal distance,single factor index method,Nemero index method and potential ecological risk index method were used to evaluate the pollution status and environmental risk of soil samples in the research area,in order to provide scientific basis for the effective prevention and control of heavy metal pollution in agricultural land soil in Dalian and the safe and healthy production of agricultural products.①The average element contents of nickel(Ni),chromium(Cr),zinc(Zn),copper(Cu)and lead(Pb)in the measured soil samples were 84.74,156.56,89.71,46.74,53.23 mg/kg,which meet the secondary standard of Soil Environmental Quality Standard(GB15618—1995).②The coefficient of variation of Hg is greater than 0.5,and the pollution source is point source pollution,likely due to human activity.③The single factor index method shows that Ni is the most serious enrichment,and the source is artificial based on the actual situation of the research area.The Nemero index shows a mild contamination of the soil in Dalian.The potential ecological risk index indicates that the farmland soil in Dalian is slightly harmful.④The soil pollution in Dalian is relatively light,and the overall level of soil quality is good,but relevant measures still need to be taken to prevent the enrichment of heavy metals and reduce the negative impact of heavy metals on the farmland soil in Dalian.