河北省保定市平原区土壤重金属污染及潜在生态危害评价

Assessment of the Heavy Metal Pollution and the Potential Ecological Hazard in Soil of Plain Area of Baoding City of Hebei Province

以河北省保定市平原区土壤为对象,采用单因子指数法和尼梅罗综合指数法对土壤重金属的环境质量及污染特征进行评价,并采用Hakanson提出的潜在生态危害指数法对土壤中重金属的潜在生态危害进行评价。结果表明:重金属污染程度依次是Cd>Zn>Hg>Cu>Pb>Cr>Ni>As,其中Cr、Pb、Ni、As都处于清洁安全状态,Hg和Cu绝大部分样点处于清洁安全状态,分别只有0.15%和0.40%处于警戒状态,Cd、Zn元素都出现污染,其中Cd面积最大,达到0.22%;综合污染评价土壤环境整体良好,清洁、安全、警戒、污染土壤面积比例分别为94.39%、5.00%、0.50%、0.11%,其中警戒及污染土壤面积为0.61%,其形成可能与工业生产及人类活动有关;各重金属元素中,产生潜在生态危害的重金属主要是Hg,已达到中等潜在生态危害水平,其余重金属均为轻度潜在生态危害,综合考虑多种重金属的潜在生态危害性,其轻微生态危害、中等生态危害、强生态危害、很强生态危害的百分比分别为93.71%、4.71%、1.29%、0.29%,整体表现为轻微潜在生态危害。

With the urban soil of plain area of Baoding city as a target, this essay evaluates the environmental quality of soil heavy metals and pollution characteristics by adopting the single factor index method and Nemerow comprehensive index method. Besides, the potential ecological hazard index suggested by Hakanson is used to assess the ecological hazard of heavy metal in urban soil. The results show that the elements, according to the pollution degree of heavy metal, are followed by the order of Cd〉Zn〉Hg〉Cu〉Pb〉Cr〉Ni〉As. Most importantly, Cr,Pb,Ni,As and most of Hg and Cu are in a clean and safe condition, only to find 0.15% of Ni and 0.40% of Cu in an alert state. However, Cd, Zn are all in the pollution state, especially the pollution of Cd represents the largest polluted area, reaching 0.22%. On the whole, Integrated Pollution Assessment showed the soil environment is good, in which clean, safe, alert, contaminated soil area ratio is 94.39%,5.00%,0.50%,0.11% respectively; and alert and contaminated soil area accounts for 0.61%. Its formation may be related to industrial production and human activities. In the heavy metal elements, resulting in potential ecological hazard of heavy metals is mainly Hg, which have reached to moderate potential ecological hazard level, the remaining heavy metals are all mild potential ecological hazard. Considering synthetically the potential ecological hazard of heavy metals, we found that the percentage of small, medium, high and strong ecological hazard is respectively 93.71%,4.71%,1.29%,0.29%. Therefore, the general performance is the small potential ecological hazard.