High cadmium concentration in soil in the Three Gorges region: Geogenic source and potential bioavailability

•High concentrations of Cd in soils of a rural area in the Three Gorges region, China, are reported.•Lognormal distribution plots and enrichment factors were applied to identify Cd sources.•Sedimentary rocks are main source of Cd in the Cd-enriched soils.•Results of sequential extractions show that...

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Bibliographic Details
Published in:Applied geochemistry 2013-10, Vol.37, p.149-156
Main Authors: Liu, Yizhang, Xiao, Tangfu, Ning, Zengping, Li, Huajun, Tang, Jiang, Zhou, Guangzhu
Format: Article
Language:English
Subjects:
Earth sciences
Earth, ocean, space
Engineering and environment geology. Geothermics
Exact sciences and technology
Geochemistry
Pollution, environment geology
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Summary:•High concentrations of Cd in soils of a rural area in the Three Gorges region, China, are reported.•Lognormal distribution plots and enrichment factors were applied to identify Cd sources.•Sedimentary rocks are main source of Cd in the Cd-enriched soils.•Results of sequential extractions show that a considerable fraction of the Cd in soils is in a labile form. This study investigated the distribution and sources of Cd in soils from a Cd-rich area in the Three Gorges region, China. The results showed that in the study area arable soils contain 0.42–42mgkg−1 Cd with 0.12–8.5mgkg−1 in the natural soils, corresponding to high amounts of Cd (0.22–42mgkg−1) in outcropping sedimentary rocks in the area. Both lognormal distribution and enrichment factor (EF) plots were applied in an attempt to distinguish between geogenic and anthropogenic origins of Cd in the local soils. The lognormal distribution plots illustrated that geogenic sources dominated in soils with low and moderate Cd concentrations (8.5mgkg−1). The enrichment factor plots illustrated that the majority of the soil samples had EF values of 5, pointing to an additional anthropogenic input of Cd to the soils. Sequential extraction results showed that Cd soluble in water and weak acid (water-soluble, exchangeable and carbonate fraction of the soil) accounts for an average of 31% of the total soil Cd, which indicates high potential for Cd mobility and bioavailability. The findings point to a potential health risk from Cd in areas with high geogenic background concentrations of this metal.
ISSN:0883-2927
1872-9134
DOI:10.1016/j.apgeochem.2013.07.022