大庆地区不同土地利用类型土壤重金属分析及生态危害评价

Soil Heavy Content Analysis and Ecological Risk Assessment of Different Landuse Types in Daqing Region

运用对照分析方法,以大庆市"七五"土壤重金属含量、黑龙江省土壤背景值和国家土壤环境质量标准为对照,对比分析大庆地区不同土地利用类型(工业用地,未利用地,草地,旱田和水田)土壤10种重金属(As、Cd、Cr、Cu、Hg、Ni、Pb、Zn、V、Mn)含量变化规律,并进行了生态危害评价。结果显示:As、Zn、Hg、Pb含量最高的是工业用地,Cd、Cr、Cu、Ni、Mn、V含量最高的是旱田,其次草地,水田和未利用地土壤重金属含量较低;对比"七五"大庆市土壤重金属含量发现,除V外,其余含量都有所增加,以Hg、As、Cd增加幅度较大,尤其是Hg污染要密切关注;土壤重金属间存在复合污染,pH与重金属间的相关性不显著,重金属与有机质、CEC相关性显著;从单项潜在危害指数(Ei)分析,工业用地Hg含量达到严重生态危害程度,土壤Cd的Ei值在5种土地利用类型中都较大,以旱田最为严重。5种土地利用类型土壤重金属综合潜在生态危害指数(RI)值排序为:R工业用地>R旱田>R水田>R草地>R未利用地,工业用地属极度潜在生态危害程度,其他利用地属轻度潜在生态危害程度。

Compared to soil heavy metal values as ＂75＂ period of Daqing city,soil background values of Heilongjiang province and the state soil environment quality standards,the content rules of ten soil heavy metals in different landuse types were analyzed by using contrast analysis method,and the assessment of ecological risk was also studied.The results showed that the contents of soil As,Zn,Hg and Pb were the highest in industrial land,and the contents of soil Cd,Cr,Cu,Ni,Mn and V were the highest in dry land.The soil heavy metal contents of grassland,unused land and paddy field were lower than others.Compared to soil heavy metal values as ＂75＂ period of Daqing city,the contents of rest soil heavy metals were increasing except soil V.The contents of soil Hg,As and Cd increased to a larger extent,and Hg pollution should be paid close attention to soil especially.The compound pollutions existed in soil heavy metals,and the correlations of pH value and soil heavy metals were not significant,but soil heavy metals and organic matter,CEC related significantly.The content of Hg of industrial land arrived to serious ecological harm degree from Ei value analysis.Ei values of soil Cd were larger in five landuse types and dry land largest.RI value order of soil heavy metal in five different landuse types was industrial landdry landpaddy fieldgrasslandunused land.Industrial land belonged to the degree of extreme potential ecological harm,and other landuses were the degree of mild potential ecological harm.