海洋胶体与痕量金属的相互作用

痕量金属的胶体结合态是海洋中金属的一种相当普遍的存在形式。胶体与痕量金属之间的相互作用影响着痕量金属在海水中的形态、迁移、生物可利用性及其归宿。总结了海洋胶体态金属的存在及其显著性,概述了胶体对金属在河口混合过程中行为的影响,并简要讨论了胶体在海水中痕量金属的固液相分配中的作用。

INTERACTIONS BETWEEN COLLOIDS AND TRACE METALS IN MARINE ENVIRONMENTS

The colloidal fraction of trace metals is ubiquitous in seawater. The interaction between marine colloids and trace metals strongly controls the speciation, bioavailability, toxicity and the ultimate fate of metals in the ocean. The significance of colloidal trace metals and the role that colloidal particles play in the behavior of metals during the estuarine mixing is overviewed in this paper. A brief discussion was finally made on the potential role of colloids in the determination of distribution coefficients between particulate and dissolved phases, WTBX]i.e.WT], the role of colloids in the solid-liquid partitioning.
The available literature data have shown a quite variation of colloidal trace metals in the total dissolved fraction. For example, colloidal Fe, Cu, Cd, Zn, Al and Pb represent 4%~100%, 1%~78%, 0%~76%, 1%~14%, 3%~100%, 12%~100% of the total dissolved metal respectively. The fundamental reasons that caused such large variations in different estuarine settings are unclear yet, which may partially be related to the different techniques and/or protocols that have been applied in separating marine colloids.
The behavior of estuarine colloidal metals is rather complex, which is primarily controlled by the association of metals and the surface of organic matter or particles. Prior research has manifested a positive correlation between certain colloidal trace metals such as Cu and colloidal organic carbon, suggesting there exist strong organic ligands for certain metals. 
The role of colloid in the interaction of metals between different phases has been claimed to be important, and the occurrence of colloids may explain the so called “particle concentration effect” on the apparent distribution coefficient. 