中文摘要：

位于三峡库区的巫山建坪地区存在明显土壤高镉（Cd）异常,但对其土壤镉分布特征及来源缺乏深入认识.通过对岩石及土壤样品中镉等重金属元素的总量、土壤理化性质、典型土壤剖面Cd含量、Cd赋存形态进行分析测试,并结合相关性分析和主成分分析等统计方法,以及不同类型土壤间的对比分析,研究了巫山县建坪地区土壤中镉等重金属的含量分布特征及其来源.结果表明,岩石（包括煤及煤矸石等）中Cd含量范围为0.22～101 mg·kg-1,表层耕作土壤中Cd含量范围为0.42～42 mg·kg-1,自然土壤中Cd含量范围为0.12～8.5 mg·kg-1;除Cd外,V、Cr、Ni、Zn同样存在富集现象.土壤中弱酸提取态镉占其总量的17%～35%.研究表明,巫山建坪研究区土壤存在严重镉污染问题,土壤中高镉与研究区岩石中镉含量具有很好的地球化学继承性,且表现出表层富集的特征.研究区土壤中镉等重金属主要为自然地质源,其历史上的煤矿开采加剧了土壤镉的富集过程.土壤中镉的生物有效态高,通过食物链富集而影响人群健康的环境危害大.

英文摘要：

Abnormally high cadmium（Cd） concentrations were existed in soils of Jianping area in the Three Gorges region,but little information is available about the geochemical distribution of Cd and source identification.In the present paper,total contents of Cd and other selected heavy metal elements,the characteristics of soil,the contents of Cd in typical soil profiles,and chemical forms of Cd in selected soils were studied.The correlation analysis,the principal component analysis,and the comparison between different soil types were conducted.The concentration distribution of Cd and selected elements in local soils was investigated and their sources were identified.The results showed that Cd in local rocks,coal and coal wastes ranged from 0.22-101 mg·kg-1,0.42-42 mg·kg-1 in the arable topsoil,and 0.12-8.5 mg·kg-1 in natural soils.The soils were also rich in other elements such as V,Cr,Ni and Zn.The weak acid fraction of Cd accounted for 17%-35% of total contents.This study demonstrated that soils from the Jianping area of Wushan County had a serious Cd pollution,and both local rocks and soils display a significant geochemical interrelation.Cd particularly accumulates in the topsoil,and it is mainly derived from the geogenic source.Human such as the historical coal mining may overload Cd in the soils.The local soils had a high portion of bioavailable Cd,through which Cd may easily transfer to and accumulate in the local crops growing in the Cd-rich soils and cause potential health risk to local residents.