【摘要】 对石家庄市污灌区上、中、下游3条剖面中的农田表层土壤重金属元素Pb、Hg、Cr、Cd、As、Cu、Zn的含量、污染状况、形态等进行了调查与研究。结果发现,研究区表层土壤中的重金属(除As外)在污灌区上、中、下游均有不同程度的富集,其中Hg、Cd含量较高,下游表层土壤中重金属平均含量均高于上、中游。运用Muller的地积累指数法进行了污染评价,结果表明,以河北省土壤背景值计算,As未对研究区表层土壤造成污染,研究区上、中、下游表层土壤受到了Hg、Cd的污染,主要为轻度—中等的污染程度。研究区表层土壤中Pb、Hg、Cr、As、Cu、Zn的形态主要为残渣态,Cd的形态主要为离子交换态和碳酸盐态,Cd具有一定的生物有效性和潜在生态危害性。更多还原

【Abstract】 In this paper,the contents and chemical speciation of Pb,Hg,Cr,Cd,As,Cu and Zn in farmland surface soils along three sections in sewage irrigation areas of Shijiazhuang City were investigated,and the heavy metal pollution was evaluated. The results show that heavy metals(with the exception of As) of surface soils along three sections in sewage irrigation areas of Shijiazhuang City have been concentrated in varying degrees:the contents of Hg and Cd are high,and the average contents of heavy metals in the downriver surface soils exceed their contents in the upriver and middle reach areas. Geoaccumulation indexes indicate that As in the surface soils has not caused pollution,and Hg and Cd in the surface soils have caused mild-moderate degrees of pollution in the surface soils,as evidenced by the arithmetic means of natural soils of Hebei Province. Chemical speciation of Pb,Hg,Cr,As,Cu and Zn in surface soils is mainly in the residual form,and Cd is mainly existent in exchangeable fractions and carbonate state. Cd has a certain degree of bioavailability and potential ecological harmfulness.更多还原