Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA, Australia; CRC for Contamination Assessment and Remediation in the Environment, University of South Australia, Mawson Lakes, SA, Australia.
J Hazard Mater. 2013 Oct 15;261:725-32. doi: 10.1016/j.jhazmat.2012.09.074. Epub 2012 Nov 3.
In this work, the nexus between sorption and bioavailability of arsenic (As) and cadmium (Cd) as affected by soil type, soil pH, ageing, and mobilizing agents were examined. The adsorption of As and Cd was examined using a number of allophanic and non-allophanic soils which vary in their charge components. The effect of pH and ageing on the bioavailability of As and Cd was examined using spiked soils in a plant growth experiment. The effect of phosphate (P)-induced mobility of As on its bioavailability was examined using a naturally contaminated sheep dip soil. The results indicated that the adsorption of both As and Cd varied amongst the soils, and the difference in Cd adsorption is attributed to the difference in surface charge. An increase in soil pH increased net negative charge by an average of 45.7 mmol/kg/pH thereby increasing cation (Cd) adsorption; whereas, the effect of pH on anion (As) adsorption was inconsistent. The bioavailability of As and Cd decreased by 3.31- and 2.30-fold, respectively, with ageing which may be attributed to increased immobilization. Phosphate addition increased the mobility and bioavailability of As by 4.34- and 3.35-fold, respectively, in the sheep dip soil. However, the net effect of P on As phytoavailability depends on the extent of P-induced As mobilization in soils and P-induced competition for As uptake by roots. The results demonstrate the nexus between sorption and bioavailability of As and Cd in soils, indicating that the effects of various factors on bioavailability are mediated through their effects on sorption reactions.
在这项工作中，研究了土壤类型、土壤 pH 值、老化和活化剂对砷（As）和镉（Cd）的吸附和生物有效性之间的关系。使用多种电荷成分不同的类水铝石和非类水铝石土壤来研究 As 和 Cd 的吸附。通过在植物生长实验中用添加污染物的土壤来研究 pH 值和老化对 As 和 Cd 生物有效性的影响。使用自然污染的绵羊浸液土壤来研究磷酸盐（P）诱导的 As 迁移对其生物有效性的影响。结果表明，As 和 Cd 在土壤中的吸附存在差异，Cd 吸附的差异归因于表面电荷的差异。土壤 pH 值的升高使净负电荷平均增加 45.7mmol/kg/pH，从而增加了阳离子（Cd）的吸附；而 pH 值对阴离子（As）吸附的影响不一致。老化使 As 和 Cd 的生物有效性分别降低了 3.31 倍和 2.30 倍，这可能是由于固定化增加所致。在绵羊浸液土壤中，磷酸盐的添加使 As 的迁移性和生物有效性分别增加了 4.34 倍和 3.35 倍。然而，P 对 As 植物有效性的净效应取决于土壤中 P 诱导的 As 迁移程度以及 P 对根吸收 As 的竞争。结果表明，土壤中 As 和 Cd 的吸附与生物有效性之间存在关联，表明各种因素对生物有效性的影响是通过它们对吸附反应的影响来介导的。
