[Cadmium and selected heavy metals in soils of Jianping area in Wushan County, the Three Gorges region: distribution and source recognition].

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 x kg(-1), 0.42-42 mg x kg(-1) in the arable topsoil, and 0. 12-8.5 mg x 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.