河水-地下水交互带内砷及金属的自然衰减过程

在简单介绍污染物自然衰减作用定义的基础上,重点分析了河水-地下水交互带内As和以矿山废水为来源的金属污染物的自然衰减行为:主要包括吸附作用,氧化还原作用,生物转化作用等。其中详细介绍了金属Fe、Al的氢氧化物/氧化物对As化合物和其他金属如Cd、Cu和Zn等的吸附作用;Ca2+、Fe2+、磷酸盐、重碳酸盐等阴阳离子和天然有机质对吸附作用的影响;金属微生物氧化还原作用以及微生物作用下As(V)与As(III)的相互转化过程。研究发现,阳离子可以增强金属的吸附作用,阴离子主要是参与竞争吸附;天然有机质对金属吸附过程的抑制作用阻碍金属的固定;交互带内氧化还原条件的变化可以引起一系列的氧化还原反应;微生物催化还原不利于As的自然衰减。最后指出目前河水-地下水交互带内金属污染物衰减过程研究存在的问题以及今后的发展方向。

Natural Attenuation of Arsenic and Metals in River-Groundwater Hyporheic Zone

Based on the definition of natural attenuation, this paper mainly analyzes the natural attenuation processes of arsenic and mining water-derived metals in the hyporheic zone, mainly including adsorption processes, oxidation and reduction processes, and biotransformation processes. And it describes in detail the iron, aluminium (hydro) oxides which have high adsorption affinities for arsenic species, cadmium, copper and zinc; the effects of anions, cations and natural organic materials on adsorption; chemical and microbial oxidation and reduction; and microbial transformation between As(V) and As(III). Studies have revealed that cations may enhance metal adsorption, anions compete with metal adsorption; the inhibitory effects of natural organic matter may interfere with metal immobilization; changes in redox conditions in the hyporheic zone may result in strong oxidation and reduction; the biologically catalyzed reduction may hinder the natural attenuation of arsenic. In addition, this paper also points out the present research gaps in this section and what future research should focus on.