石家庄市城区土壤剖面重金属含量分布特征

以石家庄市城区土壤为例,阐述了广场、居住区、公园、开发区、农田5种土地利用类型不同土壤剖面中重金属As、Cd、Co、Cu、Ni、Pb含量的分布特征,并对土壤所呈现特征的原因进行了分析,以期为城市重金属污染防治提供依据。结果表明,各重金属含量总体上都是随土层深度加深而减小,在地表有富集现象,说明人类活动对重金属含量有影响;Cd、Pb在开发区富集最为明显,Co和Ni富集于15~30 cm土层,广场土地利用类型各重金属元素都是在30~45 cm的土层含量高。Pb、Cd 2种元素垂向迁移距离较大;而As、Ni、Co 3种元素的土壤剖面的的垂向迁移不是很明显,其含量均低于土壤背景值,Cu元素迁移距离较大在公园剖面中表现最为突出,表明灌溉作用是重金属元素Cu迁移的主要原因,说明不同土地利用方式对土壤重金属含量有着明显的作用。

Distribution Characteristics of Heavy Metals in Urban Topsoil in Shijiazhuang City

In order to provide the foundation for urban pollution control,soil examples were collected from places with different land use tape in Shijiazhuang city,i.e square,resident land,park,development zone and agriculture land,heavy metals (As,Cd,Co,Cu,Ni,Pd) content in soils of these places was investigated,and the reasons for the characteristic of heavy metals content were analyzed.The results showed that the content of each element decreased with the increase of soil depth,and heavy metals presented the enrichment phenomenon in the surface,which indicated human activity influenced the content of heavy metal.The enrichment phenomenon of Cd and Pd was obvious in development zone;the enrichment phenomenon of Co and Ni element presented on 15 to 30 cm soil profile;the maximum cotent of each elements in the square presented on 30 to 45 cm soil profile.The element of Pb,Cd showed large distance of vertical migration;the vertical migration of As,Ni,Co in the soil profile was not obvious and the content of each soil profile was lower than the background values;the migration distance of Cu in the park was relatively large,which indicated that irrigation was the main reason of migration of Cu element and the different use type of land had different influence on the content of heavy metal.