The fate of non-metal contaminants in the soil environment
The fate of non-metal contaminants in the soil environment
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DOI：
10.1007/978-94-009-1626-5_2
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
R. White;A. Sharpley
中科院分区：
文献类型：
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作者：
R. White;A. Sharpley
污染物被定义为对土壤来说不是天然的物质，或者是天然存在的物质，如果其浓度超过某个阈值，则会产生不良影响。一些非金属有可能成为土壤和水的污染物。由于它们的高离子电势，周期表中第IIIA族至VIA族的非金属在其正常氧化态下形成含氧阴离子（Sposito，1984）。土壤溶液中常见的非金属含氧阴离子的例子有硼酸盐（B（OH）−4）、生物碳酸盐（HCO−3）、硝酸盐（NO−3）、硅酸盐（H3SiO−4）、硫酸盐（SO2−4）、磷酸盐（H2PO−4）、砷酸盐（AsO3−4）和硒酸盐（SeO2−4）。其他非金属如Cl和F以一价阴离子Cl−和F−的形式存在。普遍存在的Cl离子与土壤中常见的阳离子形成可溶性盐，只有当土壤溶液或地下水的盐浓度很高时才是一个潜在的问题，并且可能在植物中发生特定的Cl−毒性效应。另一方面，F−与Al 3+和Ca 2+等阳离子形成不溶性络合物，除了在大北冰洋盆地的一些地下沃茨外，很少是活性污染物。在其他阴离子中，HCO− 3自然来自于CO2在土壤水中的溶解和形成的弱碳酸的解离。硅酸盐是由矿物风化和非常弱酸性的Si（OH）4分解形成的。两者都是良性的。硫酸盐以SO2− 4和不太常见的HSO− 4形式与铁和铝氧化物的羟基表面、结晶粘土矿物的边缘表面以及吸附在带电表面上的Al 3+和羟基Al物种形成络合物。
A contaminant is defined as a substance that is not natural to the soil, or a naturally occurring substance which has undesirable effects if its concentration exceeds a certain threshold. A number of non-metals have the potential to be contaminants in soil and water. Because of their high ionic potential, non-metals of Groups IIIA to VIA of the Periodic Table in their normal oxidation states form oxyanions (Sposito, 1984). Examples of non-metal oxyanions commonly found in the soil solution are borate (B(OH)−4), biocarbonate (HCO−3), nitrate (NO−3), silicate (H3SiO−4), sulphate (SO2−4), phosphate (H2PO−4), arsenate (AsO3−4) and selenate (SeO2−4). Other nonmetals such as Cl and F occur as the monovalent anions Cl−and F−The ubiquitous ion Cl forms soluble salts with the common cations in soil and is only a potential problem when the salt concentration of the soil solution or groundwater is high and specific Cl−toxicity effects in plants may occur. On the other hand, F−forms insoluble complexes with cations such as Al3+and Ca2+and is rarely an active contaminant except in some underground waters of the Great Artesian Basin. Of the other anions, HCO−3derives naturally from the dissolution of CO2in soil water and dissociation of the weak carbonic acid formed. Silicate is formed from mineral weathering and dissociation of the very weak acid Si(OH)4. Both are benign. Sulphate as SO2−4and less commonly HSO−4forms complexes with the hydroxyl surfaces of Fe and Al oxides, the edge faces of crystalline clay minerals, and Al3+and hydroxy Al species adsorbed on charged surfaces.