山东淄博城市和近郊土壤元素地球化学特征及生态风险研究

A study of geochemical characteristics and ecological risk of elements in soil of urban and suburban areas of Zibo City, Shandong Province

以淄博城市土壤为研究对象,应用统计学方法对土壤地球化学特征进行研究,采用单因子指数和尼梅罗综合指数法对土壤环境质量进行评价,同时采用Hakanson提出的潜在生态危害指数法对土壤重金属的潜在生态危害进行评价,并对其产生的生态环境效应进行研究。结果表明:Hg、Cd、S、Pb、Se、Org C等元素或指标在表层土壤中的含量明显大于深层,二者间相关性较差,且表层土壤存在明显碱化特征,受到不同程度人为活动影响;单因子评价Cd、Cu、Hg、Ni、Zn都出现污染,其中Cd污染面积最大,达到5.11%,综合污染评价土壤环境质量整体良好,污染土壤占9.84%,其形成可能与工业生产和人类活动有关;潜在生态危害程度最强的重金属是Hg、Cd,局部地段已经达到强、极强潜在生态危害水平,综合重金属潜在生态危害水平整体表现为中等,其轻微、中等、强、很强生态危害的比例分别为29.32%、55.02%、12.85%、2.81%,从空间分布上来看,强、很强潜在生态危害区分布与各类工业空间布局相吻合,种植的蔬菜中Cd、Pb、Zn、Hg等重金属有不同程度超标现象,需加强对土壤及农产品进行协同监测与评价,防止土壤重金属污染加重影响人体健康。

Determination of chemical elements was performed in urban and suburban areas of Zibo City. For this purpose, the statistical principles, univariate and multivariate Nemerow comprehensive index, Hakanson potential ecological risk methods were applied in order to assess the geochemical characteristics of these elements, soil environment quality, potential ecological risks, and their impact on environment and crops. The investigation reveals that the values of Hg, Cd, S, Pb, Se, Org C and some othercomponents at the surface soil are significantly higher than those in deep soil, that there exists poor correlation of elements and index between surface and deep soil, and surface soil samples, affected by different degrees of human activities, are obviously alkaline. Furthermore, single pollutant evaluation shows various degrees of contamination of Cd, Cu, Hg, Ni, and Zn in soil, in which the pollution area of Cd is the biggest, accounting for 5.11% of the whole city, and the comprehensive pollutant evaluation of overall soil is effective, which reveals that 9.84% of the soil samples have been contaminated, and its formation may be associated with industrial production and human activities. Heavy metals Hg, Cd seem to be the highest potential ecological risk elements, and local area has reached strong or extreme potential ecological risk level, whereas the comprehensive potential ecological risk evaluation is overall medium, with the mild, moderate, strong and extreme harm area accounting for 29.32%, 55.02%, 12.85%,2.81%, respectively. From the spatial distribution, strong and extreme potential ecological risk areas coincide types of industrial space layout; furthermore, the values of Cd, Pb, Zn, Hg and other heavy metals of the crop samples exceed the standard limits in different degrees, which suggests that the soil and agricultural products should be monitored and evaluated cooperatively to prevent heavy metal pollution and aggravate human health.