摘要
在环境地球化学研究中,自然异常与人为异常往往同时存在,因此要判断环境污染状况,从自然异常中分离人为异常是十分重要的。文章根据重金属元素的环境地球化学行为,采用富集因子来判别河北平原表层土壤中重金属的人为污染情况。以4 km2为一个评价单元,选择Zr为标准化元素,分别以河北太行山区岩石平均值及该评价单元所对应的深层土壤样品的分析值为地球化学背景,计算得到了河北平原表层土壤中重金属元素的两组富集因子值,分别用EF和CEF表示。结果表明,除As、Ni外,其它重金属元素的EF和CEF分布特征基本一致。按CEF计算结果,该区表层土壤约有50%的区域(约40 000 km2)发生了1级轻微的重金属污染;As、Cr、Cu、Ni、Pb、Zn约有1%～5%的少部分区域发生了2级中度以上重金属污染;Cd、Hg达到2级中度污染的面积为河北平原总面积的14.7%和49.6%,达到3级显著污染级别以上分别为1.1%(880 km2)和12.6%(10 080 km2)。重金属污染主要分布在工矿区(如冀东北部地区的铁矿集区、白洋淀及周边的小冶炼厂集中区)、污灌区(如唐海县的Cd异常、石家庄及其南部的河两岸的多金属异常)、大中城镇(Hg异常)。河北平原的实例研究表明,应用富集因子可有效区分重金属污染的自然影响和人为影响。
Natural and anthropogenic anomaly coexist commonly in environmental geochemical research,so it is important to separate anthropogenic anomaly from natural anomaly in environmental impact assessment.Making use of environmental geochemical behavior of heavy metal,the authors apply Enrichment Factor to distinguish anthropogenic pollution of heavy metal from natural anomaly in topsoil in Hebei Plain.Using 4 km^2 as an evaluation unit,selecting the element Zr as the standard,taking the average of the rock from Taihang Mountain Area and the values of deep soil samples that the evaluation unit samples corresponding to as the geochemical background,we obtained two Groups of enrichment factor values of heavy metals in surface soils from Hebei Plain.And we show them by EF and CEF respectively.The results show that besides As and Ni,the distribution characteristics of EF and CEF for other elements are almost the same.According to CEF results,about 50% of the surface area（about 40 000 km^2） occurred in slightly heavy metal pollution（I level pollution）;For the elements of As、Cr、Cu、Ni、Pb and Zn,about 1%～5% of the region occurred in moderate heavy metal pollution（Ⅱ level pollution）;For Cd and Hg,the area to achieve the moderate heavy metal pollution（Ⅱ level pollution）,accounting for the whole area of Hebei plain are 14.7% and 49.6%,the area to achieve the significant pollution（Ⅲ level or above） are 1.1%（880 km^2） and 12.6%（10 080 km^2）.Heavy metal pollution mainly distributed in industrial and mining areas（such as iron ore areas in northeast of Hebei,Baiyangdian Lake and the surrounding area of the small smelter）,irrigation area（such as the abnormal Cd in Tanghai County,Shijiazhuang and the two sides of the xiao river which is located in southern Shijiazhuang） and the large and middle city（Hg anomaly）.The results show that it is feasible of application of an enrichment factor to determine anthropogenic contamination of heavy metal in topsoil.
出处
《生态环境学报》
CSCD
北大核心
2010年第4期786-791,共6页
Ecology and Environmental Sciences
基金
中国地质调查局地质大调查项目"河北省农业地质调查"(200414200007)
