土壤中溶解性有机质及其对污染物吸附和解吸行为的影响

DISSOLVED ORGANIC MATTER AND ITS EFFECTS ON ADSORPTION AND DESORPTION OF POLLUTANTS IN SOILS

溶解性有机质（DOM）已成为环境科学、生态学和土壤科学等学科的研究热点。DOM对重金属、养分和有机污染物的环境化学行为有很大影响，因此开展DOM与污染物（或养分）之间相互作用的研究，具有重要的理论与实践意义。本文系统地评述了DOM的来源、组成、分级及其对土壤中污染物吸附一解吸行为的影响。尽管关于土壤中DOM的研究还不完善，许多工作也只是刚刚开始，至今对土壤中DOM的性质、组成和分类方法等问题都不是很清楚，但现有的结果已经表明，DOM是土壤圈中一种十分活跃的重要化学组分，它对土壤中化学物质的溶解、吸附、解吸、吸收、迁移和生物毒性等行为均有显著的影响。

Growing attention has been paid to the study on dissolved organic matter (DOM), a complex mixture of' similar' organic compounds, in the fields of environmental science, ecological science and soll science since the chemical,physical and biological behaviors of many micronutrients, heavy metals and organic pollutants in soil-plant system are concerned with DOM. The sources. components,fractations, transformation and transport of soll DoM, and the relations between soil DOM and pollutants are reviewed in the presented paper. Although much more studies on soil DOM should be conducted to understand the behaviors of soil DOM and its relations to chemicals in the future. it is clearly indicated that the concentration of soil DOM is very low, usually less than several percentages of the total soil organic matter. is an important active chemical component in soils. Heavy metal adsorption is reduced with the presence of DOM. Researchers widely believe that the solution, desorption, transport, leaching, bio-accumulation and some other processes of pollutants are enhanced predominately due to their complexation with DOM and/or adsorption on DOM. Larger amounts of potentially pollutants will be leached into underground waters and surface waters or accumulated in foods if the pollutants coexist with DOM. Many elements and organic compounds in soil waters have solubility much higher than expected from theoretical calculations based on their solubility in pure water. Presumably there may be a mechanism of dissolution by DOM, but no document validates the hypothesis.