含铁介质稳定砷与根际微生物的相互作用
Interactions Between Stabilized Arsenic by Fe-based Media and Soil Microbes in the Rhizosphere
通讯作者: 罗锡明(1967-), 男,河北保定人,教授,主要从事海岸带地质环境、场地污染修复研究. E-mail:luoxm@cugb.edu.cn
收稿日期: 2020-07-15 修回日期: 2020-09-20 网络出版日期: 2020-11-30
基金资助: |
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Corresponding authors: Luo Ximing (1967-), male, Baoding City, Hebei Province, Professor. Research areas include geological environment of the coastal zone, site contamination remediation. E-mail:luoxm@cugb.edu.cn
Received: 2020-07-15 Revised: 2020-09-20 Online: 2020-11-30
作者简介 About authors
殷怡童(1997-),女,浙江定海人,硕士研究生,主要从事污染修复研究.E-mail:kaqichuan@163.com
对原位修复后植物复植区土壤中被稳定砷的稳定性进行评估是环境风险评价的重要内容,含铁介质稳定砷与根际微生物的相互作用是环境风险评价的关键。根据近5年的相关研究进展,从含铁介质修复砷污染土壤、砷污染土壤中的微生物群落结构特征及根际微生物参与的含铁介质中砷的释放过程3个方面来进行综述。综述发现,含铁介质是稳定土壤中砷的重要材料,但修复效果易受到环境变化和微生物作用的影响。在含铁介质稳定砷之后,土壤中的微生物群落会受到修复试剂的影响进而形成新的群落结构,而在继续进行植物复植后,由于根际环境作用,微生物群落结构还会发生进一步的演化从而最终形成新的微生物群落结构。在这个演化过程中,微生物与所接触的砷和铁的界面反应是影响土壤中砷的稳定性的重要因素,因此研究含铁介质稳定砷与根际微生物的相互作用具有重要意义。此外,对植物复植后根际微生物与含铁介质稳定砷的稳定性之间的关系进行了展望,旨在为更好地认识土壤复杂环境中砷的迁移提供参考。
关键词:
Assessment of the stability of stabilized arsenic in soils in revegetated areas after in-situ restoration has been regarded as a key component in environmental risk assessment, while the interaction between stabilized arsenic by Fe-based media and soil microbes in the rhizosphere is also critical for environmental risk assessment. According to the relevant research progress in the last five years, the paper elucidated three key aspects of this problem: Arsenic-contaminated soil remediation with iron containing media, structural characterization of microbial communities in arsenic-contaminated soil, and the arsenic-releasing process that involves the participation of rhizosphere microorganisms on the Fe-based media. This review finds that Fe-based media is an essential material for stabilizing arsenic in soil, but its impact is strongly affected by circumstance change and microbial action. After arsenic stabilization, microbial communities in the soil would be changed by Fe-based reagents, then the further evolution of microbial community structure will occur during continuing revegetation because of rhizosphere effect, and finally new microbial communities will form. In this process, the interface reaction between rhizosphere microbes and iron containing media with arsenic is an important factor affecting the stability of arsenic in soils. Therefore, it is of great significance to understand this interaction in the future. Furthermore,the reaction between rhizosphere microorganisms in revegetated areas and the stability of stabilized arsenic was also discussed. The purpose of this paper was to provide more information for the mobility of arsenic in the complex soil environment.
Keywords:
本文引用格式
殷怡童, 罗锡明.
Yin Yitong, Luo Ximing.
1 引 言
土壤修复的目的包括降低污染物在土壤环境中的迁移风险、生态风险、健康风险,以及改善受污染的土壤以便于后期恢复植被,因此为了更好地评估植物复植后土壤中被化学稳定砷的稳定性,结合近年来国内外研究现状(图1),我们发现与砷污染相关的关键词主要包括固定/稳定化、含铁介质、土壤微生物群落结构等。内容涉及了含铁介质修复砷、砷污染土壤微生物群落和微生物反应等。因此本文从含铁介质修复砷污染土壤、砷污染土壤中的微生物群落结构特征以及根际微生物参与含铁介质中砷的释放过程反应3个方面进行综述。
图1
2 含铁介质修复砷污染土壤
2.1 含铁介质的固化机理
含铁介质对土壤中砷的固定/稳定主要以2种方式进行:吸附、络合作用,沉淀或共沉淀作用。其中沉淀或共沉淀作用是利用砷氧阴离子与部分矿物发生铁砷沉淀或硫砷沉淀,以形成难溶的沉淀化合物或次生矿物[9]。然而在实际污染场地中,基于含铁介质的吸附和络合作用才是修复的主要方式。吸附可分为化学反应(形成内圈络合物)和物理吸附(形成外圈络合物)两类,有研究表明,AsO
2.2 近期常用含铁介质评估
含铁介质是有效稳定土壤中砷的材料之一,至今为止,由于其吸附性能,已经对多种含铁介质应用于修复被砷污染的土壤进行了广泛的研究。
在自然界中存在的各种铁矿物一直都是人们研究稳定砷的主要材料。自然界的铁(氢)氧化物根据不同的结晶程度,可以分成两大类含铁矿物:其中无定形或弱结晶型铁矿物包括水铁矿(ferrihydrite,5Fe2O3·9H2O或Fe5HO8·4H2O)、施威特曼石[schwertmannite,(Fe8O8(OH)8-2x(SO4)x;1<X<1.75)]和微晶针铁矿(δ-FeOOH)等,而针铁矿(α-FeOOH)、赤铁矿(α-Fe2O3)、纤铁矿(γ-FeOOH)、磁赤铁矿(γ-Fe2O3)等都属于晶型铁矿物。
无定形或弱结晶型的铁氧化物是当前最有效的稳定剂之一。但无定形或弱结晶型的铁氧化物并不总是稳定的,并且会受到环境的强烈影响,例如冻融循环会降低无定形氧化铁的含量;而它在土壤中也往往会逐渐转变为晶型铁氧化物,从而显示出较低的砷吸附能力[19]。
铁氧化物及其前体、纳米铁、新兴含铁材料等均可作为修复砷污染的含铁介质,表1中列出了其稳定砷的效果,因为纳米铁材料和各类新兴含铁材料具有相对较高的吸附能力,因此有着广阔的应用前景。而自然界中存在着大量的自然含铁矿物,因此通过将自然含铁矿物机械活化以应用于稳定砷有可能成为新的选择。
表1 含铁介质修复土壤效果案例
Table 1
土壤类型 | 土壤pH | 砷浓度/(mg/kg) | 含铁介质 | 用量 | 修复效率/% |
---|---|---|---|---|---|
矿区石灰性始成土[34] | 7.6 | 3 197 | 施威特曼石(FeOS) | 10% | 99 |
矿山壤砂土[15] | 8.2 | 247 | 水铁矿 | 5% | 91 |
金锑矿的沉积区[24] | 4.6 | 479 | 合成水铁矿 | 3% | 84 |
金锑矿的沉积区[24] | 4.6 | 479 | 氯化铁+石灰 | 1∶1 | 71 |
金锑矿的沉积区[24] | 4.6 | 479 | 零价铁粉末 | 1% | 90 |
砷污染土壤[27] | 7.4 | 228 | 机械活化褐铁矿 | 10% | 78 |
矿山边缘土壤[35] | 6.3 | 2 548 | 磁赤铁矿纳米颗粒 | 5% | 99 |
棕地子区域A[31] | 6.4 | 70 200 | 零价纳米铁 | 10% | 92 |
棕地子区域B[31] | 6.4 | 25 900 | 零价纳米铁 | 10% | 91~95 |
自然高砷土壤[36] | 6.1 | 15 910 | 零价铁纳米粉 | 1% | 60 |
砷污染土壤[13] | 3.6 | 1 400 | 铁铈氧化物 铁铈氧化物 铁铈氧化物 | 2% 2% 2% | 84~98 |
砷污染土壤[13] | 7.2 | 200 | |||
砷污染土壤[13] | 5.0 | 800 |
由此可见,含铁介质是良好的稳定砷材料。但向砷污染土壤中添加的含铁介质的稳定效率及稳定性会受到各种土壤环境化学和生物因素的影响,因此在实际应用前,应对修复位点的土壤环境进行调研,了解土壤类型、土壤pH、总砷浓度以及砷污染土壤中的微生物群落结构等信息。
3 砷污染土壤中的微生物群落结构特征
3.1 砷污染土壤及修复后土壤中微生物群落
图2
而对于污染土壤中的真菌群落,Zygomigota、担子菌门(Basidiomycota)、子囊菌门(Ascomycota)是相对优势的门,最丰富的属是毛霉属(Mucor)、被孢霉属(Mortierella)、Cryptococcus(隐球酵母属)和Pseudotomentella[46]。
在门水平上,发现在砷污染较轻的位置,酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)、芽单胞菌门(Gemmatimonadetes)和疣微菌门(Verrucomicrobia)相对要丰富得多,其中Chloroflexi与总砷浓度呈负相关;而放线菌门(Actinobacteria)和蓝细菌(Cyanobacteria)在污染严重位置明显富集,且Actinobacteria、变形菌门(Proteobacteria)和浮霉菌门(Planctomycetes)与总砷浓度呈正相关[37,39]。在纲水平上浮霉菌纲(Planctomycetia)和α-变形杆菌纲(Alphaproteobacteria)与总砷浓度呈正相关,β-变形杆菌纲(Betaproteobacteria)与总砷浓度呈负相关,因此在高砷胁迫下,属于Alphaproteobacteria的细菌被确定为受污染土壤中的主要微生物群落,而Betaproteobacteria则将在土壤中消失[37,41]。希瓦氏菌属(Shewanella)和Steroidobacter常见于砷含量较高的土壤中而梭菌科(Clostridiaceae)、地杆菌属(Geobacter)、节细菌属(Anthrobacter)、紫色杆菌属(Janthinobacterium)、假单胞菌属(Pseudomonas)与总砷浓度呈正相关[38~41,47]。在真菌中,随着砷污染的增加,Basidiomycota的相对丰度趋于增加[46]。
零价纳米铁颗粒是更常应用的土壤修复材料,对土壤微生物的影响似乎较为复杂。零价纳米铁的添加虽然可以通过引起氧化胁迫来抑制金属(类金属)污染土壤中丛枝菌根真菌的发育和功能,但也会增加土壤中Shewanella的丰度,零价纳米铁对沙壤土土壤微生物的抑制作用相较于黏土壤土更加明显,这是因为土壤有机质的作用[8,51,52]。添加泡沸石负载的零价纳米铁后,属于Firmicutes的优势属芽孢杆菌属(Bacillus)、类芽孢杆菌属(Paenibacillus)和环脂酸芽孢杆菌属(Alicyclobacillus)的相对丰富度显着增加,相对的,抑制了革兰氏阴性细菌(黄单胞菌科(Xanthomonadaceae)、马赛菌属(Massilia)和溶杆菌属(Lysobacter))的生长[12]。最终部分细菌被淘汰并推动了本地细菌群落的重建,新的微生物群落在土壤复植后又经历新的演化过程,最终形成新的种群结构。复植后土壤微生物群落的演化在一定程度上是影响稳定化砷重新释放的重要因素。
3.2 砷污染土壤及修复后植物根际微生物群落
根际是连接植物、土壤和微生物的纽带,根际土壤作为土壤的一个重要的子系统,也因此导致其特性与土壤基质完全不同[36]。植物复植会对已有的土壤环境微生物群落结构造成影响,且由于根际效应,与植被区非根际土壤相比,根际土壤中具有更高的微生物群落。
在工矿复垦区,自然恢复根际微生物与种植植物根际微生物丰度和多样性具有很大差异[53];且与没有植被的地点相比,经过植被恢复地点的细菌、真菌密度更高[54]。Tipayno等[55]强调在高度污染的土壤中引入植物后明显发生细菌群落的重组。Sun等[56]研究了铜矿尾矿中3种先锋植物的根际细菌群落的多样性和结构,发现根际土壤中的Alphaproteobacteria,δ-变形杆菌纲(Deltaproteobacteria)、Chloroflexi、Acidobacteria和Gemmatimonadetes显示出相对较高的相对丰度;相反,在裸露的尾矿中,γ-变形杆菌纲(Gammaproteobacteria)和Firmicutes占细菌群落的大部分。在富砷土壤中生长的蜈蚣草的根际中Proteobacteria、Actinobacteria和Chloroflexi的相对丰度增加[57]。甚至于在砷污染的水稻田中,由于铁斑的存在,水稻根部具有铁斑的部分、根际土壤和非根际土壤的微生物群落结构存在差异,根际土壤中以Acidobacteriales、黏球菌目(Myxococcales)和除硫单胞菌目(Desulfuromonales)为主,而根部铁斑部位的菌群富含假单胞菌目(Pseudomonadales)、伯克霍尔德氏菌目(Burkholderiales)、鞘脂单胞菌目(Sphingomonadales)和根瘤菌目(Rhizobiales)[58]。
在使用含铁介质修复的砷污染土壤中种植植物,根据植物种类不同,根际微生物群落之间存在的差异也会很大。由于水稻是世界上最重要的农作物之一,且在水稻种植期间交替的水淹条件会极大地改变土壤的氧化还原条件并影响砷的形态,因此,近年来对砷污染稻田土壤的修复进行了大量深入研究。有研究称Fe-Mn-Ce改性生物炭增加了砷污染稻田土壤中土壤酶的活性,并极大地影响了根际微生物,包括Proteobacteria, Acidobacteria和Gemmatimonadetes的相对丰度[61]。在整个水稻种植期间,根际硫酸盐还原菌的相对丰度会随着钛石膏(主要由结晶石膏和无定形氢氧化铁组成)的添加而增加,但铁还原菌相对丰度变化不大[62]。而在添加了纳米零价铁改性生物炭的水稻根际,Geobacter的相对丰度增加但真菌中的Ascomycota的相对丰度降低[63]。
综上所述,砷浓度和含铁介质的添加都会对土壤中的微生物群落结构造成影响,并且在植物复植后,由于复杂的根际行为,也会使微生物群落的结构发生改变。对于被污染土壤的修复区,复植后的非根际土壤及根际土壤微生物群落对研究环境中铁和砷的微生物反应以及被固定砷的稳定性有着重要意义,然而对这方面的研究文献较少,因此有必要展开相关工作,特别是根际微生物与固定砷的含铁介质在界面上的反应是揭示微生物与矿物界面反应机制的重要环节。
4 根际微生物参与含铁介质中砷的释放过程
4.1 含铁介质还原溶解释放砷
在异化铁还原细菌存在下,氧化铁(羟基氧化物)的生物还原通常受微生物细胞外电子转移过程中的3种不同策略控制。第一种策略是直接接触机制,需要微生物与电子受体[例如,Fe(III)-氧化物]之间足够的接触面积,涉及铁还原酶和细胞色素[66,67]。第二种策略是由电子穿梭控制的,它可以加速某些特定的氧化还原反应[64,68]。第三种策略使用导电的纤毛(菌毛)介导的机制,其中纤毛在特定异化铁还原细菌的细胞与氧化铁(羟基氧化物)之间转移电子[69]。Shewanella和Geobacter是已知最重要的异化铁还原细菌属,已经建立了微生物铁还原的生理生化模型[70],其中Geobacter sulfreducens是将导电纤毛(菌毛)和细胞色素组合在一起的代表性物种[71]。
发现在富含砷的根际土壤中与Fe(III)还原(e.g., Geothrix fermentans, Geobacter pickeringii, Carboxydocella ferrireducens, Geobacter argillaceus, Geobacter toluenoxydans),SO
4.2 砷从吸附位点解吸
砷从含铁介质上的还原解吸是砷的另一个释放途径。微生物参与砷的解吸过程一般都认为优先进行As(V)的还原,因为含铁介质对As(III)的吸附比对As(V)的吸附性低得多,并且As(III)迁移性较强,当As(V)被还原成As(III)后,As(III)易于从含铁介质上解吸下来。不过也有研究表明,Shewanella putrefaciens可能通过细菌磷酸基或羧酸基与铁矿物相互作用,促进As(V)解吸至可溶性相,然后再还原溶解的As(V)[79]。
砷的微生物还原主要涉及2种机制,砷抗性系统和砷还原系统。砷抗性系统涉及的还原酶ArsC存在于细胞质中,对于进入细胞的水溶态As(V),能够将其还原并外排,属于解毒作用。砷还原系统的呼吸性砷酸盐还原酶Arr(由亚基ArrA和ArrB组成)位于细胞外周胞质中或作为膜结合的周质蛋白,在周质中具有催化位点[80]。
因为2种酶在细胞中的分布位置不同,因此有研究认为仅具有ArsC的微生物不能直接还原被吸附在介质上的砷,而具有Arr的微生物可还原吸附在土壤或合成矿物上的砷[81]。但有研究发现土壤中ArsC相对丰度与As(III)浓度呈正相关[42]。Meharg等[82]提出,细胞质途径在土壤中起着更重要的作用,因为细胞质中砷的还原是由多种微生物在有氧和厌氧条件下进行的,而异化砷的还原仅是由少数微生物在厌氧条件下进行的。宏基因组学分析中所观察到的,土壤中arsC的丰度比arrA的丰度更高,使这一观点得到了支持[83]。然而另一方面,有研究提供了土壤DNA的证据,表明arrA基因的丰度和群落成员与土壤砷浓度有关,但arsC基因没有发现关系[84]。
在厌氧呼吸中使用As(V)作为末端电子受体的含有呼吸砷酸盐还原酶(arr)的微生物称为异化砷酸盐呼吸原核生物(Dissimilatory Arsenate-Respiring Prokaryotes,DARPs)。DARPs在严格的厌氧条件下通过利用有机化学物质或无机化学物质作为末端电子给体(Terminal Electron Donor,TED)将As(V)还原为As(III),包括Shewanella,脱亚硫酸菌属(Desulfitobacterium),脱硫芽孢弯曲菌属(Desulfosporosinus),Bacillus,Geobacter和硫磺单胞菌属(Sulfurospirillum)[85~89]。此外硫酸盐还原细菌可以利用通过硫酸盐还原过程所产生的硫化物来还原被吸附的As(V)[90]。
由于富集砷,根际土壤中Deltaproteobacteria的相对丰度较高,且Deltaproteobacteria纲内的一些属因其在多种环境中对铁、砷和硫的还原作用而闻名[57,70,91]。部分Shewanella,Geobacter和硫酸盐还原细菌被发现即能够还原As(V)也能够还原Fe(III),因此可能同时释放Fe(II)和As(III)[92,93],例如近期发现Shewanella putrefaciens同时还原了As(V)和水铁矿[94]。另一方面,发现氧化铁纳米颗粒可以用作促进土壤微生物种群,尤其是Geobacter呼吸的电子导管,并且可以增强Geobacter介导的水铁矿还原[95,96]。因此,还需要进一步研究微生物与固定砷的含铁介质的界面反应。
图3
5 展 望
由于砷污染土壤借由食物链影响着植物动物以及人类,因此修复被砷污染的土壤已经是当今关注的重点方向。使用含铁介质原位稳定砷污染土壤,被视为一种常用有效的修复方法。但由于多种因素影响,该方法固定的砷容易发生二次活化而再释放到环境中。前文内容大致从含铁介质固定砷、砷铁影响土壤中微生物以及微生物参与含铁介质中砷的释放3个方面进行了综述。通过对相关文献进行分析,发现当今对于污染土壤中的微生物群落的研究中,微生物主要作为被影响因子或者诊断污染状况的环境指标,通过改变其他环境条件从而导致微生物群落结构特征发生改变,并通过某类微生物相对丰度的变化和土壤环境中相关元素的变化来推测环境中发生的主要微生物反应,但由于土壤环境较为复杂,此类推测也存在问题。有文献研究了施用单种微生物对土壤环境中砷铁的影响,但仍缺乏有关复杂微生物群落(例如根际微生物)对土壤环境中砷铁作用的研究。同时,近几年对于砷迁移的研究对象主要为稻田土壤,缺乏对普遍土壤环境及较为常见植物根际环境的研究,并且在含铁介质固定砷方面大多为研究含铁介质固定砷的有效性以及通过多种评价方法例如植物指示法来评估土壤中砷的稳定性的短期实验,相对的,缺乏植物复植后对砷修复效果稳定性的长期研究。因此需要将含铁介质固定砷与复植根际微生物串联在一起,进一步提出复植根际微生物作用可能对固砷铁介质产生的影响。
因此今后的研究重点应该集中在以下3个方面:
同时复植后土壤根际环境和微生物群落在砷和铁的地球环境命运中起着重要作用,一方面,微生物本身是砷和铁生物转化的主要动力,另一方面植物根际作用也会对砷铁的地球化学循环和微生物群落造成影响,因此对于植物根际—微生物—固砷含铁介质在土壤中的长期相互作用以及可能会对其他金属浓度造成影响的研究是极其有必要的。这有助于我们进一步评估植物复植后土壤中固砷的稳定性。
参考文献
The broad scope of health effects from chronic arsenic exposure: Update on a worldwide public health problem
[J]. ,
Global burden of cancer and coronary heart disease resulting from dietary exposure to arsenic, 2015
[J]. ,
Factors controlling arsenic contamination and potential remediation measures in soil-plant systems
[J]. ,
Arsenic contamination, consequences and remediation techniques: A review
[J]. ,
From classic methodologies to application of nanomaterials for soil remediation: An integrated view of methods for decontamination of toxic metal(oid)s
[J]. ,
Heavy metal immobilization by cost-effective amendments in a contaminated soil: Effects on metal leaching and phytoavailability
[J]. ,
Nano zero-valent iron aging interacts with the soil microbial community: A microcosm study
[J]. ,
Review of remedying the arsenic-contaminated soil with Fe-based media
[J]. ,
含铁介质用于修复砷污染土壤研究综述
[J].,
Simultaneous inner- and outer-sphere arsenate adsorption on corundum and hematite
[J]. ,
Speciation and surface structure of inorganic arsenic in solid phases: A review
[J]. ,
Zeolite-supported nanoscale zero-valent iron for immobilization of cadmium, lead, and arsenic in farmland soils: Encapsulation mechanisms and indigenous microbial responses
[J]. ,
Stabilizing effects of Fe-Ce oxide on soil As(Ⅴ) and P
[J]. ,
铁铈氧化物对土壤As(Ⅴ)和P的稳定化效果
[J].,
Immobilization of As(III) in soil and groundwater using a new class of polysaccharide stabilized Fe-Mn oxide nanoparticles
[J]. ,
Evaluation of ferrihydrite as amendment to restore an arsenic-polluted mine soil
[J]. ,
Chemical stabilization of metals and arsenic in contaminated soils using oxides—A review
[J]. ,
Phosphate reactions with natural allophane, ferrihydrite and goethite
[J]. ,
Effect of freeze-thaw cycles on stabilizing arsenic contaminated soil by iron-containing materials
[J]. ,
冻融循环对含铁材料稳定砷污染土壤的影响
[J].,
Goethite surface reactivity: III. Unifying arsenate adsorption behavior through a variable crystal face—Site density model
[J]. ,
Selected Fe and Mn (nano)oxides as perspective amendments for the stabilization of As in contaminated soils
[J]. ,
Adsorption and mechanism of arsenic by natural iron-containing minerals
[J]. ,
天然含铁矿物对砷的吸附效果及机制
[J].,
Arsenic and heavy metal mobility in iron oxide-amended contaminated soils as evaluated by short- and long-term leaching tests
[J]. ,
Evaluation of amendments to reduce arsenic and antimony leaching from co-contaminated soils
[J]. ,
Immobilization of Cu and As in two contaminated soils with zero-valent iron—Long-term performance and mechanisms
[J]. ,
The effect of nanocrystalline magnetite size on arsenic removal
[J]. ,
Stabilization of soil arsenic by natural limonite after mechanical activation and the associated mechanisms
[J]. ,
Impact of iron and manganese nano-metal-oxides on contaminant interaction and fortification potential in agricultural systems—A review
[J]. ,
Application of Nanoscale Zero Valent Iron (NZVI) for groundwater remediation in Europe
[J]. ,
Comparing different commercial zero valent iron nanoparticles to immobilize As and Hg in brownfield soil
[J]. ,
Nanoremediation and long-term monitoring of brownfield soil highly polluted with As and Hg
[J]. ,
Stabilization of arsenic in soil by nano-TiO_2 and Fe supported on activated carbon
[J]. ,
活性炭负载纳米二氧化钛及铁修饰改性对土壤砷的稳定化试验研究
[J].,
Stabilization of arsenic-contaminated soils using Fe-Mn oxide under different water conditions
[J]. ,
铁锰氧化物在不同水分条件下对土壤As的稳定化作用
[J].,
Arsenic immobilization in the contaminated soil using poorly crystalline Fe-oxyhydroxy sulfate
[J]. ,
Is nanoremediation an effective tool to reduce the bioavailable As, Pb and Sb contents in mine soils from Iberian Pyrite Belt?
[J] ,
Effect of nano zero-valent iron application on As, Cd, Pb, and Zn availability in the rhizosphere of metal(loid) contaminated soils
[J]. ,
Interaction among soil physicochemical properties, bacterial community structure, and arsenic contamination: Clay-induced change in long-term arsenic contaminated soils
[J]. ,
Study of arsenic-contaminated soil bacterial community using biochip technology
[J]. ,
Response of soil microbial communities to elevated antimony and arsenic contamination indicates the relationship between the innate microbiota and contaminant fractions
[J]. ,
Bacterial response to antimony and arsenic contamination in rice paddies during different flooding conditions
[J]. ,
Bacterial community and arsenic functional genes diversity in arsenic contaminated soils from different geographic locations
[J]. ,
Depth-resolved microbial community analyses in two contrasting soil cores contaminated by antimony and arsenic
[J]. ,
Microbial community composition and functions are resilient to metal pollution along two forest soil gradients
[J]. ,
Response of microbial activity and microbial community composition in soils to long-term arsenic and cadmium exposure
[J]. ,
Exposure of soil microbial communities to chromium and arsenic alters their diversity and structure
[J]. ,
Fungal community structure and As-resistant fungi in a decommissioned gold mine site
[J]. ,
An integrated insight into the response of sedimentary microbial communities to heavy metal contamination
[J]. ,
Red mud-modified biochar reduces soil arsenic availability and changes bacterial composition
[J]. ,
Toxicity of metal oxide (CeO2, Fe3O4, SnO2) engineered nanoparticles on soil microbial biomass and their distribution in soil
[J]. ,
Response of soil microbial communities to additions of straw biochar, iron oxide, and iron oxide-modified straw biochar in an arsenic-contaminated soil
[J]. ,
Nano Zero-Valent Iron Mediated Metal(loid) uptake and translocation by arbuscular mycorrhizal symbioses
[J]. ,
The impact of nanoscale zero-valent iron particles on soil microbial communities is soil dependent
[J]. ,
Comparison of different methods for analyzing the rhizosphere microbial diversity of different plants in industrial and mining reclamation areas
[J]. ,
不同方法分析工矿复垦区不同植物根际微生物多样性的比较
[J].,
Soil biological attributes in arsenic-contaminated gold mining sites after revegetation
[J]. ,
T-RFLP analysis of structural changes in soil bacterial communities in response to metal and metalloid contamination and initial phytoremediation
[J]. ,
Restoration with pioneer plants changes soil properties and remodels the diversity and structure of bacterial communities in rhizosphere and bulk soil of copper mine tailings in Jiangxi Province, China
[J]. ,
Arsenic-enrichment enhanced root exudates and altered rhizosphere microbial communities and activities in hyperaccumulator Pteris vittata
[J]. ,
Arsenic contamination influences microbial community structure and putative arsenic metabolism gene abundance in iron plaque on paddy rice root
[J]. ,
Influence of Fe3O4 nanoparticles on lettuce(Lactuca sativa L.)growth and soil bacterial community structure
[J]. ,
纳米Fe3O4对生菜生长及土壤细菌群落结构的影响
[J].,
Iron oxide magnetic nanoparticles deteriorate the mutual interaction between arbuscular mycorrhizal fungi and plant
[J]. ,
Effect of Fe-Mn-Ce modified biochar composite on microbial diversity and properties of arsenic-contaminated paddy soils
[J].,
Simultaneous immobilization of the cadmium, lead and arsenic in paddy soils amended with titanium gypsum
[J]. ,
Effects of modified biochar on rhizosphere microecology of rice (Oryza sativa L.) grown in As-contaminated soil
[J].,
The state of arts:Sources,microbial processesand ecological effects of iron in the marine environment
[J]. ,
海洋环境中铁的来源、微生物作用过程及生态效应
[J]. ,
Enriched iron(III)-reducing bacterial communities are shaped by carbon substrate and iron oxide mineralogy
[J]. ,
Fe(III) Oxide reduction by a gram-positive thermophile: Physiological mechanisms for dissimilatory reduction of poorly crystalline Fe(III) oxide by a thermophilic Gram-positive Bacterium Carboxydothermus ferrireducens
[J]. ,
The role of microorganisms in the geochemical iron cycle
[J]. ,
微生物在地球化学铁循环过程中的作用
[J].,
Shewanella secretes flavins that mediate extracellular electron transfer
[J]. ,
Aromatic amino acids required for Pili conductivity and long-range extracellular electron transport in Geobacter sulfurreducens
[J]. ,
Microorganisms pumping iron: Anaerobic microbial iron oxidation and reduction
[J]. ,
Cyclic voltammetry of biofilms of wild type and mutant Geobacter sulfurreducens on fuel cell anodes indicates possible roles of OmcB, OmcZ, type IV pili, and protons in extracellular electron transfer
[J]. ,
Goethite reduction by a neutrophilic member of the alphaproteobacterial genus telmatospirillum
[J]. ,
Predominant but previously-overlooked prokaryotic drivers of reductive nitrogen transformation in paddy soils, revealed by metatranscriptomics
[J]. ,
Excessive input of phosphorus significantly affects microbial Fe(III) reduction in flooded paddy soils by changing the abundances and community structures of Clostridium and Geobacteraceae
[J]. ,
Mechanisms for Fe(III) oxide reduction in sedimentary environments
[J]. ,
Siderophore-Producing Rhizobacteria as a promising tool for empowering plants to cope with iron limitation in saline soils: A review
[J]. ,
Novel plant growth promoting rhizobacteria—Prospects and potential
[J]. ,
Evidence for ligand hydrolysis and Fe(III) reduction in the dissolution of goethite by desferrioxamine-B
[J]. ,
Influence of arsenate adsorption to ferrihydrite, goethite, and boehmite on the Kinetics of arsenate reduction by Shewanella putrefaciens strain CN-32
[J]. ,
Genetic mechanisms of arsenic detoxification and metabolism in bacteria
[J]. ,
Integrated phytobial remediation for sustainable management of arsenic in soil and water
[J]. ,
A global survey of arsenic-related genes in soil microbiomes
[J]. ,
Community dynamics of As(V)-reducing and As(III)-oxidizing genes during a wet-dry cycle in paddy soil amended with organic matter, gypsum, or iron oxide
[J]. ,
arrA is a reliable marker for As(V) respiration
[J]. ,
Mobilization of arsenite by dissimilatory reduction of adsorbed arsenate
[J]. ,
Removal of arsenic from contaminated soils by microbial reduction of arsenate and quinone
[J]. ,
Arsenate respiratory reductase gene (arrA) for Desulfosporosinus sp. strain Y5
[J]. ,
Effect of extracellular electron shuttles on arsenic-mobilizing activities in soil microbial communities
[J]. ,
Mobilization of arsenic on nano-TiO2 in soil columns with sulfate reducing bacteria
[J]. ,
The ecology and biotechnology of sulphate-reducing bacteria
[J]. ,
Arsenic dissolution from Japanese paddy soil by a dissimilatory arsenate-reducing bacterium Geobacter sp. OR-1
[J]. ,
Mutational and gene expression analysis of mtrDEF, omcA and mtrCAB during arsenate and iron reduction in Shewanella sp. ANA-3
[J]. ,
Characterising microbial reduction of arsenate sorbed to ferrihydrite and its concurrence with iron reduction
[J]. ,
Respiratory interactions of soil bacteria with (semi)conductive iron-oxide minerals
[J]. ,
Maghemite (gamma-Fe2O3) nanoparticles enhance dissimilatory ferrihydrite reduction by Geobacter sulfurreducens: Impacts on iron mineralogical change and bacterial interactions
[J]. ,