吉林省黑土区土壤重金属污染特征及生态风险评价

Pollution Characteristics and Ecological Risk Assessment of Soil Heavy Metals in Black Soil Area of Jilin Province

以吉林省黑土区作为研究区域,利用随机布点的方法采集26个土壤样品进行调查研究,采用单因子污染指数法、内梅罗污染指数法、地积累指数法和富集系数法分析研究区内土壤重金属的污染特征。结果表明,土壤样品中Cu、Mn、As、Zn、Cr、Ni、Pb这7种重金属元素的平均含量均超过吉林省重金属元素背景值,其中Pb的含量最高,高于背景值6.44倍。参照《土壤环境质量标准》(GB 15618—1995),As、Cu、Pb、Cr、Zn、Ni的平均单项污染指数分别为1.103、0.369、0.282、0.301、0.278、1.725,说明研究区土壤主要受到Ni和As污染。内梅罗综合污染指数为1.298,表明研究区土壤总体达到轻度污染的程度。Ni的超标样点共20个,超标率达76.9%;As的超标样点2个,超标率为7.7%;Pb的超标样点只有1个,超标率为3.8%,其余元素均未超标。地积累指数法和富集系数法的评价结果显示研究区内土壤环境中Pb达到了显著污染的程度,Ni、Cr、Cu、As为中度污染,Fe、Mn、Zn为轻微污染程度,并未造成污染。

Taking the black soil area of Jilin Province as the research area,26 soil samples were collected for investigation and research using the random distribution method,single-factor pollution index method,Nemerow pollution index method,geo-accumulation index method and enrichment coefficient method were used to analyze the pollution characteristics of soil heavy metals in the study area.The results showed that the average content of the seven heavy metal elements(Cu,Mn,As,Zn,Cr,Ni,Pb)in the soil samples exceeded the background value of heavy metal elements in Jilin Province,and the content of Pb was the highest,which was 6.44 times higher than the background value.According to"Soil Environmental Quality Standards"(GB 15618-1995),the average single pollution indexes of As,Cu,Pb,Cr,Zn and Ni were 1.103,0.369,0.282,0.301,0.278 and 1.725,respectively,indicating that the soil in the study area was mainly affected by Ni and As pollution.Nemoro pollution index was 1.298,indicating that the soil in the study area generally reached the level of mild pollution.Ni exceeded the standard in 20 samples,with exceeding rate of 76.9%.There were 2 over-standard samples of As,the over-standard rate was 7.7%;the concentration of Pb was found to be higher than the standard value in one soil sample,and the over-standard rate was 3.8%;the other elements were all within limits.The evaluation results of geo-accumulation index method and enrichment factor index method showed that Pb in soil in the study area was significantly polluted,Ni,Cr,Cu and As were moderately polluted,Fe,Mn and Zn were slightly polluted but not polluted.