Change of the Extractability of Cadmium Added to Different Soils: Aging Effect and Modeling

文献类型： 外文期刊

第一作者： Zhang, Xi

作者： Zhang, Xi;Zhang, Xi;Zeng, Saiqi;Chen, Shibao;Ma, Yibing

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关键词： aging; cadmium; ethylenediaminetetraacetic acid; semi-mechanistic model; soil

期刊名称：SUSTAINABILITY （ 影响因子：3.251； 五年影响因子：3.473 ）

ISSN： 2071-1050

年卷期： 2018 年 10 卷 3 期

页码：

收录情况： SCI

摘要： Ethylenediaminetetraacetic acid (EDTA) is known to be a chelating agent and has been widely used for estimating the total extractable metals in soil. The effect of aging on EDTA-extractable cadmium (Cd) was investigated in five different soils at three Cd concentrations incubated for 180 days. The EDTA-extractable Cd rapidly decreased after incubated during 30-60 days, followed by slow processes, and for 90 days the EDTA-extractable Cd tended to be stable. The decrease in EDTA-extractable Cd may be due to precipitation/nucleation processes, diffusion of Cd into the micropores/mesopores, and occlusion within organic matter in soils. A semi-mechanistic model to predict the extractability of Cd during incubation, based on processes of Cd precipitation/nucleation, diffusion, and occlusion within organic matter, was developed and calibrated. The results showed that the processes of micropore/mesopore diffusion were predominant processes affecting the extractability of Cd added to soils, and were slow. However, the proportions of the processes of precipitation/nucleation and occlusion within organic matter to the non-EDTA-extractable Cd added to soils were only 0.03-21.0% and 0.41-6.95%, respectively. The measured EDTA-extractable Cd from incubated soils were in good agreement with those predicted by the semi-mechanistic model (R-2 = 0.829). The results also indicated that soil pH, organic matter, and incubation time were the most important factors affecting Cd aging.

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