中文摘要：

基于典型的希瓦氏金属还原菌（Shewanella decolorationis S12）和石英砂负载铁砷（As-IOCS）的相互作用,探讨了不同来源及组分溶解有机质和生物/非生物条件下对上述作用过程的影响.结果表明,不同类型及组分溶解有机质（DOM）均能使石英砂上负载的铁砷微生物还原解离/解吸程度得到一定程度的加强.而非生物反应体系中,只有含氧化还原敏感官能团结构的蒽醌类物质（0.1mmol·L^-1AQS）对铁砷的解离/解吸作用产生明显影响.在0.1mmol·L^-1AQS和有机络合物（2mmol·L^-1EDTA）的影响下,使得石英砂上负载铁的微生物异化还原程度加强,导致As（Ⅴ）从石英砂负载铁上的解吸程度也随之得到加强;在未加菌体系中,AQS和EDTA和不同组分的DOM类似,对As（Ⅴ）从IOCS上解吸程度影响微弱.对于As（Ⅲ）来说,只有在AQS的影响下,其含量得到显著增加,这可能是作为氧化还原中介体的AQS,在厌氧的生物/非生物条件下,能促进电子在As不同形态之间的转移,使得高价态As（Ⅴ）向还原态As（Ⅲ）的还原转变更易进行.当S12菌液接种含量增加时,在污泥不同组分DOM的影响下,As（Ⅴ）的解吸程度在反应300h前得到明显加强,而As（Ⅲ）的含量在整个反应期间,均快速上升,表明菌液含量高的体系,微生物铁异化还原过程得以持续进行,同时也促进了As（Ⅴ）向As（Ⅲ）的还原转变.

英文摘要：

To resolve the role of DOM in regulating arsenic environmental behavior,we examined As desorption from ferrihydrite-coated sands presorbed with As（Ⅴ） and its redox transformation influenced by the different fractions of DOM extracted from sludge mediated by the dissimilatory iron reducing bacterium Shewanella decolorationis S-12.The influence of different fractions of DOM on the microbial reductively dissolution of ferric（hydr）oxides and release of arsenic to the aqueous phase could be seen during the incubation time,and the degree and extend were enhanced significantly when S12 inoculum concentration increased from 2%（V/V）to 20%（V/V） or after addition of 0.1 mmol · L^-1AQS and 2 mmol · L^-1 EDTA.However,in parallel abiotic experiment,the obvious dissolution of ferric（hydr）oxides and release of arsenic can be noticed only in reaction system containing 0.1 mmol · L^-1 AQS.Similar to that of the total arsenic,the tendency of As（Ⅴ） release from presorbed ferrihydrite-coated sands was strengthened by the addition of 0.1 mmol · L^-1 AQS and 2 mmol · L^-1 EDTA,while compared to abiotic control experiment,the ability of the release enhancement by addition of 0.1 mmol · L^-1 AQS and 2 mmol · L^-1 EDTA was slim.for the obvious release of As（Ⅲ）,whether in biotic or abiotic experiments,can only be seen in reaction system containing 0.1 mmol · L^-1 AQS.In high S12 inoculum concentration,the elevated release of As（Ⅲ） could be influenced by fractions of DOM except eluted fraction within 300 hours incubation.The release enhancement of As（Ⅴ） by different fractions of DOM could obviously noticed in the whole incubation time.