天然水环境中的溶解有机物及其光化学降解对重金属生物可利用性的影响

Photochemical Degradation of Dissolved Organic Matter in the Natural Aquatic Environment and Its Effect on Binding of Heavy Metals

溶解有机物(DOM)在控制水生生态系统的化学、生物和物理特性中起着重要的作用。DOM不仅能够结合黏土颗粒,而且也能结合对环境和生物有重要影响的Hg,Cu,Pb,Cd,Ni等重金属和有机污染物,从而改变这些物质的迁移、生物可利用性和毒性。本文综述了天然水环境中DOM与重金属的相互作用和对其生物可利用性的影响,并对影响DOM光化学降解的因素及其对重金属生物可利用性的影响做了总结。已有的研究表明:DOM的结构、分子量、浓度、重金属种类、水环境条件等均会影响到DOM与重金属污染物的相互作用;光化学降解会显著改变DOM与重金属的相互作用,从而使其生物可利用性发生变化。

Dissolved organic matter（DOM） plays an important role in regulating the chemical, biological and physical characteristics in aquatic systems. Not only clay particles, but also many environmentally and biologically important heavy metals（e, g. Hg, Cu, Pb, Cd, Ni） and organic pollutants, can be bound with DOM, thus modifying their transportation, bioavailability and toxicity. The effects of DOM properties（molecular weight, chemical structure etc）, water chemistry（e, g. pH, ion strength etc） and photochemical degradation of DOM on the affinities of DOM for binding heavy metals, as well as their influences on the toxicity and bioavailability of heavy metals are reviewed in this paper. Since photochemical degradation is one of the most important ways for alteration of DOM in natural environment, factors influencing DOM photochemical degradation and the effect on the toxicity of heavy metals are also summarized.