Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, China.
Chemosphere. 2013 Jun;91(11):1502-7. doi: 10.1016/j.chemosphere.2012.12.026. Epub 2013 Feb 21.
Cadmium (Cd), through human activities, has severely accumulated in purple soil. Purple soil is considered as one of the most important types of agricultural soil in Southern China. In this study, we investigated the release of Cd from 13 purple soils with a wide range of total Cd content collected from vegetable fields and forestlands in Sichuan Basin. Soil batch extraction and column leaching experiments were conducted to determine the influence of chemical speciation, soil properties, soil water contact time, and soil/water ratio on the release characteristics of Cd from soil. Results indicate that Cd release was primarily present in exchangeable, carbonate-bound, and organically bound fractions. Moreover, precipitation-induced, long-term saturated conditions enhance the release of Cd from soil to water. Multiple regression analysis also shows that the release of Cd from soil is related to pH level, organic matter amount, and total Cd content in native soil. This finding explains the Cd release variation of 86% and 95% during batch extraction and column leaching experiments, respectively. Finally, this investigation provides a more convenient way of evaluating potential ecological risks of Cd in purple soil by determining the properties of several common soil types.
镉（Cd）通过人类活动在紫色土壤中严重积累。紫色土壤被认为是中国南方最重要的农业土壤类型之一。在这项研究中，我们调查了从四川盆地蔬菜地和林地采集的总镉含量范围很广的 13 种紫色土壤中镉的释放情况。通过土壤批量提取和柱浸实验，确定了化学形态、土壤性质、土壤与水接触时间和土壤/水比对土壤中镉释放特征的影响。结果表明，镉的释放主要存在于可交换态、碳酸盐结合态和有机结合态。此外，沉淀诱导的长期饱和条件会增强镉从土壤向水中的释放。多元回归分析还表明，土壤中镉的释放与土壤的 pH 值、有机质含量和原生土壤中的总镉含量有关。这一发现解释了在批量提取和柱浸实验中，镉的释放变化分别为 86%和 95%。最后，通过确定几种常见土壤类型的性质，本研究为评估紫色土壤中镉的潜在生态风险提供了一种更便捷的方法。
