UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
Chemosphere. 2010 May;79(8):763-71. doi: 10.1016/j.chemosphere.2010.03.003. Epub 2010 Mar 23.
The solution speciation of a metal has a critical influence on its biological activity in the environment and is now an important focus of research. In this review, pertinent aspects related to the aqueous speciation and chemistry of cobalt (Co) in terrestrial environments are critically assessed. Although there is a lack of comprehensive data on aqueous Co concentrations in soil porewaters, groundwaters and surface waters, existing reports indicate that natural Co concentrations vary within a picomolar to micromolar range. Cobalt chemistry is dominated by the Co(II) oxidation state in the aqueous phase of terrestrial environments primarily due to the extremely low solubility of Co(III). There is no universal agreement on the importance of Co(II) complexation in the solution phase of terrestrial environments and, furthermore, on the nature of the major binding organic ligands. The kinetics of Co(II) complexation to, and dissociation from, natural organic complexing ligands are such that the speciation of Co is likely to significantly diverge from estimates based on thermodynamic equilibrium calculations. As a result, an accurate understanding of Co bioavailability, toxicity and transport in terrestrial aquatic environments will only be achieved when thermodynamics can be reconciled with reaction kinetics.
金属的形态对其在环境中的生物活性有至关重要的影响，因此现在成为了研究的重点。本综述批判性地评估了有关钴（Co）在陆地环境中水溶液形态和化学性质的相关方面。尽管土壤孔隙水、地下水和地表水的水溶液中 Co 浓度缺乏全面的数据，但现有报告表明，天然 Co 浓度在皮摩尔至微摩尔范围内变化。在陆地环境的水相中，Co 化学性质主要由 Co(II)氧化态主导，这主要是由于 Co(III)的溶解度极低。对于 Co(II)在陆地环境溶液相中的络合的重要性，以及主要结合有机配体的性质，尚未达成普遍共识。Co(II)与天然有机络合配体的络合和离解动力学使得 Co 的形态很可能与基于热力学平衡计算的估计值有很大差异。因此，只有当热力学能够与反应动力学相协调时，才能准确理解 Co 在陆地水生环境中的生物利用度、毒性和迁移。
