厌氧微生物作用下沉积物中砷的形态转化与环境行为研究  

Transformation and Environmental Behavior of Arsenic in Sediments Under Microbial Activities

作　　者：王洁[1,2] 许丽英[1] 王新[1] 贾永锋[1] 

机构地区：[1]中国科学院沈阳应用生态研究所,污染生态与工程重点实验室,沈阳110016 [2]中国科学院大学,北京100049

出　　处：《矿物岩石地球化学通报》2015年第2期310-315,共6页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金项目(41273133)

摘　　要：为了研究厌氧微生物作用下沉积物中砷的形态转化及固液界面的分配过程对砷的环境行为与归趋的影响,通过采集锦州湾清洁沉积物进行负载砷,利用微生物培养与非生物培养实验,对比研究厌氧微生物作用下砷铁硫共还原条件下污染体系中砷的环境行为与归趋。实验结果表明在培养的42 d周期内,液相的总砷量首先砷浓度保持降低趋势,而后再次升高。在培养第3-7 d时液相的As^5＋迅速被还原,约26%的溶解态砷从液相移除,97%以上的As^5＋被还原为As^3＋。同时微生物作用下固相中90%以上铁氧化物矿物逐渐转化为次生的亚铁矿物,固相中结晶态铁氧化物发生明显活化,而硫酸盐还原产物硫离子综合调控体系中游离的亚铁离子和As^3＋。因此,厌氧微生物还原条件下,砷,铁,硫同步发生还原,硫离子调控体系中砷和铁环境行为,硫化亚铁成为亚铁矿物的主要形态,硫化砷是砷的主要归趋。The goal of this study is to find out the fate of arsenic in reductive environments like sediment environment where the fate of arsenic is strongly influenced by microbial activities. A clean sediment loaded with arsenic was use in this experiment to simulate the transformation of arsenic under activities of microbial in the reductive environment. The concentration fluctuation of aqueous arsenic, P-extraction arsenic and the HCl-extraction arsenic were observed. Arsenic, iron oxides and sulfate were reduced strongly. More than 97% arsenic as well as iron oxides were reduced and 26% dissoluble arsenic turned into insoluble forms after 3-7days. Meanwhile the sediment system became more complex with the participation of produced sulfides. Based on evidences, we concluded that the fate of arsenic is strongly impacted by products of Fe and S. The reductions of Fe, As and S were happened simultaneously, S^2- controls the environmental behaviors of Fe, the ferric form FeS is the main species of S, and AsS is the main destination of arsenic.

关 键 词：沉积物 砷 微生物还原 形态转化 

分 类 号：P593[天文地球—地球化学]