平潭岛土壤重金属污染评价及生态风险研究

Evaluation of Soil Heavy Metals Pollution and Ecological Risk Assessment in Pingtan Island

对平潭岛土壤表层重金属污染特征及生态危害程度进行研究,野外采集并测定了土壤样本中V、Cr、Mn、Co、Cu、Zn、Pb 7种重金属含量,综合运用内梅罗综合污染指数法和污染负荷指数法两种评价方法对土壤重金属污染状况进行评价,并采用Hakanson潜在生态风险指数法对平潭岛土壤重金属进行潜在生态风险评估.结果表明:除Cu元素外,V、Cr、Mn、Co、Zn、Pb 6种元素平均值均低于福建省土壤背景值;从空间分布上看,7种重金属元素均呈现明显的聚集性和点源污染特征.平潭岛Cu元素单项污染指数平均值大于1,V、Cr、Mn、Co、Zn、Pb 6种元素单项污染指数平均值小于1,7种重金属元素污染水平大小顺序为Cu> Mn> Zn> Co> Pb> V> Cr;结合内梅罗综合污染指数和污染负荷指数,流水镇的东北沿海与正东边沿海区域土壤受到重金属污染.平潭岛7种重金属元素土壤生态风险等级均为轻度危害等级,RI指数结果最大值也低于轻度危害临界值,平潭岛土壤整体未受到来自7种重金属元素的胁迫作用,但是部分高值污染区域需要引起一定的重视.

In order to pollution and its ecological understand the characteristics of damage Pingtan island surface soil heavy metals degree, soil samples were collected from the field and seven heavy metals content which are V, Cr, Mn, Co, Cu, Zn, Pb were measured. Two kinds of evaluation methods, Nemerow comprehensive pollution index and pollution load index, were used to get the soil heavy metal pollution status. In addition, Hakanson potential ecological risk index was used to assess Pingtan island heavy metal＇s potential ecological risk. The results show that： Except for Cu element, other six heavy metals which were V, Cr, Mn, Co, Zn and Pb average value were lower than Fujian province soil background value ; From the view of spatial distribution, seven heavy me, tals all showed obvious aggregation and point source pollution characteristics. The average single pollution index value of Pingtan island Cu element was greater than 1, the average single pollution index values of the other six heavy metal elements which were V, Cr, Mn, Co, Zn, Pb were all less than 1. The order of seven heavy metals pollution level was Cu 〉 Mn 〉 Zn 〉 Co 〉 Pb 〉 V 〉 Cr. Com- bined with Nemerow comprehensive pollution index and pollution load index, the soil along the northeast and east coastal area of Liushui town was polluted by heavy metals. The soil ecological risk grade of 7 heavy metal elements in Pingtan island were mild hazard level, the maximum value of the RI index was also lower than the mild hazard level critical value. The whole soil in Pingtan island was not stressed by seven heavy metals, however, part high-value pollution areas need to be paid more attention.