这项工作是共同的 BRGM, 博士后授予来自总参谋部杜 Loiret 和卡诺研究所。我们还感谢 Région 中心--卢瓦尔河谷向枢纽项目提供的财政支助。

1. 实验准备
<ol>
	<li>酸洗所有材料 (玻璃, 聚四氟乙烯 (PFTE)) 与样品接触 (5 天在20% 硝酸 (硝酸3) v/v) 然后5天在盐酸 (HCl) 10% v/v)。用超纯水冲洗多次, 并在使用前在层流罩下干燥。</li>
	<li>使用聚乙烯手套 (或类似) 和油烟罩的所有步骤涉及化学品。</li>
</ol>
2. 制备 Hg 和非晶态铁氧化物
<ol>
	<li>准备大约20克 ferryhydrate (Fe (OH)3): 溶解50克 FeCl3-6H2O 在500毫升超纯水 (电阻率和 #62; 18 ω cm-1) 在一个不锈钢叶轮或磁性玻璃反应器搅拌下搅拌器.初始 pH 值为和 #60; 2。</li>
	<li>手动添加10米氢氧化钠溶液沉淀 ferryhydrate。 注: 大约50毫升将需要沉淀所有的铁 (氧) 氢氧化物。调整 pH 值为 6, 保持1小时的搅拌稳定。<ol>
		<li>对于 Hg 刺 (氧) 氢氧化: 准备10毫升的 HgNO3 at 10 克 L-1 , 并添加350µL 到 (氧) 氢氧化溶液。 注: 这将产生最后的汞含量的湿 (氧) 氢氧化物的〜4µg g-1 (氧) 氢氧化。</li>
		<li>对于加氧氢氧化物: 准备100毫升的2O325在 10 g L-1和添加70毫升的氧化铁溶液。这将产生一个最终的 (III) 含量为70毫克/克 (氧) 氢氧化物。</li>
	</ol>
	</li>
	<li>用不锈钢叶轮或磁力搅拌器搅拌3小时, 然后离心20分钟, 2000 x g. 去除上清液, 在500毫升超纯水中 re-suspend (氧) 氢氧化物。重复离心和冲洗步骤两次。恢复湿 (氧) 氢氧化物 (固体的含水率为85-90% 重量), 并贮存在4° c 直到使用。</li>
	<li>通过伽玛辐射对湿汞或 As 尖铁氧化物进行消毒, 最小吸收辐射剂量为 25 25kgy。</li>
	<li>控制 Hg 和作为 (氧) 氢氧化物内容
	<ol>
		<li>确定颗粒的汞含量26。 注意: 我们发现3.90 ±0.08 µg Hg g-1实体。因此, 18.3 克氧化铁中每列添加的汞总量为71.4 ±1.51 µg。</li>
		<li>确定作为内容在药丸。采用热酸性矿化 (8 毫升 5 N HCL 为4小时50° c), 并通过原子吸收光谱法 (AAS) 进行分析。 注意: 我们发现70毫克为 g-1实体。因此, 18.3 克氧化铁中添加到柱中的总用量为 ~ 1.3 克。</li>
	</ol>
	</li>
</ol>
3. 制备二氧化硅凝胶和砂基
注: 一种松散的硅胶基质用于阻止在水流下从沙子/氧化铁混合物中迁移的细铁氧化物。最后的凝胶基质是6% 硅胶, 以不形成一个区块, 但只是松散聚集的氧化物。
<ol>
	<li>准备一个10% 硅胶混合物, 加热4克硅胶在40毫升的解决方案 7% KOH 在一个热板上, 搅拌与磁搅拌棒, 直到溶解。</li>
	<li>加入60毫升超纯水, 然后冷却解决方案〜20° c。用稀释的磷酸 (20%) 快速滴定到 pH 值7.5。然后迅速混合的液体硅胶与320克无菌砂和先前添加18.3 克汞-尖或作为尖刺的氧化铁之前, 它固化。</li>
	<li>在步骤4中使用前, 将 "jellified" 混合物与刮刀混合并保持不育。</li>
</ol>
4. 设置列
<ol>
	<li>使用带水套冷却系统的玻璃柱 (内部容积 = 400 毫升, 高度 = 30 厘米, 直径3.5 厘米) 和五石英隔膜定期设置 (每5厘米) 沿列, 使您可以沿列取样。</li>
	<li>切割聚四氟乙烯管 (ptfe int Ø 3 mm), 以确保足够的长度在列的入口和出口。将流入的软管连接到水/介质供应。</li>
	<li>用灭菌 (1 小时110° c) 对所有材料 (玻璃、管材) 进行灭菌。</li>
	<li>垂直附加列。</li>
	<li>将水套与水冷系统连接, 以保持平均温度为20° c。</li>
	<li>从顶部填充列, 如下所示: -一层潮湿的岩棉, 以避免固体损耗; -320 克无菌砂 (枫丹白露砂, D50 = 209 µm); -320 克无菌砂混合18.3 克水合无定形氧化铁与汞或作为 (见步骤 1) 和固定在一个6% 硅胶矩阵 (见步骤 2)。</li>
	<li>在低速 (~ 2 mL h-1) 上垂直连接列, 并将连续 N2气泡超纯无菌水的上升流连在一起。</li>
	<li>用铝箔盖住柱子以保护光线。</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56240/56240fig1v2.jpg"> 
图 1:列设置的草绘和照片<a href="//ecsource.jove.com/files/ftp_upload/56240/56240fig1v2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

<ol>
	<li>Oremland, R. S., Stolz, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Ecology+of+Arsenic.">The Ecology of Arsenic.</a> Science. 300 (5621), 939 (2003).</li><li>Silver, S., Phung, L. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genes+and+enzymes+involved+in+bacterial+oxidation+and+reduction+of+inorganic+arsenic.">Genes and enzymes involved in bacterial oxidation and reduction of inorganic arsenic.</a> Appl Environ Microbiol. 71 (2), 599-608 (2005).</li><li>Compeau, G. C., Bartha, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sulfate-Reducing+Bacteria:+Principal+Methylators+of+Mercury+in+Anoxic+Estuarine+Sediment.">Sulfate-Reducing Bacteria: Principal Methylators of Mercury in Anoxic Estuarine Sediment.</a> Appl. Environ. Microbiol. 50, (1985).</li><li>Fleming, E. J., Mack, E. E., Green, P. G., Nelson, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mercury+Methylation+from+Unexpected+Sources:+Molybdate-Inhibited+Freshwater+Sediments+and+an+Iron-Reducing+Bacterium.">Mercury Methylation from Unexpected Sources: Molybdate-Inhibited Freshwater Sediments and an Iron-Reducing Bacterium.</a> Appl. Environ. Microbiol. 72 (1), 457-464 (2006).</li><li>Barkay, T., Miller, S., Summers, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+mercury+resistance+from+atoms+to+ecosystems.">Bacterial mercury resistance from atoms to ecosystems.</a> FEMS Microbiol Rev. 27 (2-3), 355-384 (2003).</li><li>Dixit, S., Hering, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+arsenic(V)+and+arsenic(III)+sorption+onto+iron+oxide+minerals:+Implications+for+arsenic+mobility.">Comparison of arsenic(V) and arsenic(III) sorption onto iron oxide minerals: Implications for arsenic mobility.</a> Environ. Sci. Technol. 37, (2003).</li><li>Andersson, H. A., Nriagu, J. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Biochemistry of Mercury in the Environnment. , 79-112 (1979).</li><li>Khwaja, A., Bloom, P. R., Brezonik, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Binding+Constants+of+Divalent+Mercury+in+Soil+Humic+Acids+and+Soil+Organic.">Binding Constants of Divalent Mercury in Soil Humic Acids and Soil Organic.</a> Environ. Sci. Technol. 40, (2006).</li><li>Neculita, C. M., Zagury, G. J., Deschenes, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mercury+Speciation+in+Highly+Contaminated+Soils+from+Chlor-Alkali+Plants+Using+Chemical+Extractions.">Mercury Speciation in Highly Contaminated Soils from Chlor-Alkali Plants Using Chemical Extractions.</a> J Environ Qual. 34 (1), (2005).</li><li>Schuster, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+behaviour+of+mercury+in+the+soil+with+special+emphasis+on+complexation+and+adsorption+processes+-+a+review+of+the+literature.">The behaviour of mercury in the soil with special emphasis on complexation and adsorption processes - a review of the literature.</a> Water Air Soil pollut. 56 (56), 667-680 (1991).</li><li>Wallschl&#228;ger, D., Desai, M. V. M., Spengler, M., Windm&#246;ller, C. C., Wilken, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+humic+substances+dominate+mercury+geochemistry+in+contaminated+floodplain+soils+and+sediments.">How humic substances dominate mercury geochemistry in contaminated floodplain soils and sediments.</a> J. Environ. Qual. 27 (5), (1998).</li><li>Lovley, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissimilatory+Fe(III)+and+Mn(IV)+reduction.">Dissimilatory Fe(III) and Mn(IV) reduction.</a> Microbiol. Mol. Biol. Rev. 55 (2), 259-287 (1991).</li><li>Lovley, D. R., Kashefi, K., Vargas, M., Tor, J. M., Blunt-Harris, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+of+humic+substances+and+Fe(III)+by+hyperthermophilic+microorganisms.">Reduction of humic substances and Fe(III) by hyperthermophilic microorganisms.</a> Chem. Geol. 169 (3-4), 289-298 (2000).</li><li>Hansel, C. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+constraints+of+ferric+(hydr)oxides+on+dissimilatory+iron+reduction+and+the+fate+of+Fe(II).">Structural constraints of ferric (hydr)oxides on dissimilatory iron reduction and the fate of Fe(II).</a> Geochimica Cosmochimica Acta. 68, 3217-3229 (2004).</li><li>Thamdrup, B., Fossing, H., J&#248;rgensen, B. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Manganese,+iron+and+sulfur+cycling+in+a+coastal+marine+sediment+Aarhus+bay,+Denmark.">Manganese, iron and sulfur cycling in a coastal marine sediment Aarhus bay, Denmark.</a> Geochim.Cosmochim. Acta. 58 (23), 5115-5129 (1994).</li><li>Planer-Friedrich, B., London, J., McCleskey, R. B., Nordstrom, D. K., Wallschl&#228;ger, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thioarsenates+in+Geothermal+Waters+of+Yellowstone+National+Park:+Determination,+Preservation,+and+Geochemical.">Thioarsenates in Geothermal Waters of Yellowstone National Park: Determination, Preservation, and Geochemical.</a> Environ. Sci. Technol. 41 (15), 5245-5251 (2007).</li><li>Burnol, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decoupling+of+arsenic+and+iron+release+from+ferrihydrite+suspension+under+reducing+conditions:+a+biogeochemical+model.">Decoupling of arsenic and iron release from ferrihydrite suspension under reducing conditions: a biogeochemical model.</a> Geochem. Trans. 8 (1), 12 (2007).</li><li>Kocar, B. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrated+biogeochemical+and+hydrologic+processes+driving+arsenic+release+from+shallow+sediments+to+groundwaters+of+the+Mekong+delta.">Integrated biogeochemical and hydrologic processes driving arsenic release from shallow sediments to groundwaters of the Mekong delta.</a> Appl. Geochem. 23 (11), (2008).</li><li>Harris-Hellal, J., Grimaldi, M., Garnier-Zarli, E., Bousserrhine, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mercury+mobilization+by+chemical+and+microbial+iron+oxide+reduction+in+soils+of+French+Guyana.">Mercury mobilization by chemical and microbial iron oxide reduction in soils of French Guyana.</a> Biogeochem. 103 (1), (2011).</li><li>Islam, F. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+metal-reducing+bacteria+in+arsenic+release+from+Bengal+delta+sediments.">Role of metal-reducing bacteria in arsenic release from Bengal delta sediments.</a> Nature. 430, (2004).</li><li>Schultz-Zunkel, C., Rinklebe, J., Bork, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trace+element+release+patterns+from+three+floodplain+soils+under+simulated+oxidized-reduced+cycles.">Trace element release patterns from three floodplain soils under simulated oxidized-reduced cycles.</a> Ecol. Eng. 83, 485-495 (2015).</li><li>Nickson, R. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+arsenic+release+to+groundwater,+bangladesh+and+West+Bengal.">Mechanisms of arsenic release to groundwater, bangladesh and West Bengal.</a> App. Geochem. 15, 403-413 (2000).</li><li>Varsanyi, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arsenic,+iron+and+organic+matter+in+sediments+and+groundwater+in+the+Pannonian+basin,+Hungary.">Arsenic, iron and organic matter in sediments and groundwater in the Pannonian basin, Hungary.</a> App. Geochem. 21, 949-963 (2006).</li><li>Hellal, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mercury+mobilization+and+speciation+linked+to+bacterial+iron+oxide+and+sulfate+reduction:+A+column+study+to+mimic+reactive+transfer+in+an+anoxic+aquifer.">Mercury mobilization and speciation linked to bacterial iron oxide and sulfate reduction: A column study to mimic reactive transfer in an anoxic aquifer.</a> J. Contam. Hydrol. 180, 56-68 (2015).</li><li>Battaglia-Brunet, F., Dictor, M. C., Garrido, F., Crouzet, C., Morin, D., Dekeyser, K., Clarens, M., Baranger, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+arsenic(III)-oxidizing+bacterial+population:+selection,+characterization,+and+performance+in+reactors.">An arsenic(III)-oxidizing bacterial population: selection, characterization, and performance in reactors.</a> J Appl. Microbiol. 93 (2002), 656-667 (2002).</li><li>Salvato, N., Pirola, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+mercury+traces+by+means+of+solid+sample+atomic+absorption+spectrometry.">Analysis of mercury traces by means of solid sample atomic absorption spectrometry.</a> Microchim Acta. 123 (1), 63-71 (1996).</li><li>Huguet, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Caract&#233;risation biog&#233;ochimique et potentiel de m&#233;thylation du mercure de biofilms en milieu tropical (retenue de Petit Saut et estuaire du Sinnamary, Guyane Fran&#231;aise). . , (2009).</li><li>Mamindy-Pajany, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arsenic+in+Marina+Sediments+from+the+Mediterranean+Coast:+Speciation+in+the+Solid+Phase+and+Occurrence+of+Thioarsenates.">Arsenic in Marina Sediments from the Mediterranean Coast: Speciation in the Solid Phase and Occurrence of Thioarsenates.</a> Soil Sed. Contam. 22, 984-1002 (2013).</li><li>dos Santos Afonso, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reductive+dissolution+of+iron(III)+(hydro)oxides+by+hydrogen+sulfide.">Reductive dissolution of iron(III) (hydro)oxides by hydrogen sulfide.</a> Langmuir. 8, 1671-1675 (1992).</li><li>Postma, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Redox+zonation:+equilibrium+constraints+on+the+Fe(III)/SO4-reduction+interface.">Redox zonation: equilibrium constraints on the Fe(III)/SO4-reduction interface.</a> Geochem Cosmochim. Acta. 60, 3169-3175 (1996).</li><li>Kumar, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sulfur+and+oxygen+isotope+tracing+in+zero+valent+iron+based+In+situ+remediation+system+for+metal+contaminants.">Sulfur and oxygen isotope tracing in zero valent iron based In situ remediation system for metal contaminants.</a> Chemosphere. 90, 1366-1371 (2013).</li></ol>

作者没有什么可透露的。

实验柱的设置证明是一个方便的实验室设备, 研究厌氧生物地球化学过程中的连续条件。连续柱系统允许在比泥浆批处理系统或缩影更接近实际含水层的条件下工作。连续系统可以模拟地下水通过含水层沉积物的流动。
该协议中最关键的步骤是制备 TE 铁 (氧) 氢氧化物和硅凝胶和沙子的混合物, 这需要迅速创建, 以获得均匀的质地。除了这一一般关键步骤之外, 还必须仔细设计?...

了解和预测环境中的微量元素 (TE) 移动性和地球化学是至关重要的, 以便监测、开发和适用污染场址的适当管理决策。这尤其适用于有毒的附加费, 如砷 (as) 和汞 (汞) 的情况。这些污水附加费在土壤或含水层中的命运和形态与物理化学条件密切相关, 如 Eh 和 pH, 也与可以直接作用于物种形成或对流动的间接作用的微生物活动有关。
的确, 有些细菌可以直接氧化为 (iii) 至 as (v) 或减少为 (v) 至 as (iii)。这影响作为毒性, 因为 (iii) 是作为和流动性的最毒的形式, 因为 (iii) 比作为 (V) 更流动, 能容易地吸附对铁 (氧) 氢氧化物或有机物质1,2。同样, 细菌强烈参与水星循环, 或者通过它的甲基化, 主要由硫酸盐和铁减少的细菌3,4, 形成神经毒素一甲基汞 (容易生物在食物链中),或通过其还原为挥发性单质 Hg (Hg°)5。
砷和汞的命运也与土壤或含水层组成密切相关, 因为有机物质或铁 (氧) 氢氧化物等化合物可以影响它们的螯合和生物利用度。作为 (V) 吸附井对铁 (氧) 氢氧化物6, 而 Hg 有非常高亲和性为有机物 (om; 主要为硫醇基团), 但也为胶体铁或锰 (氧) 氢氧化在 OM 耗尽的环境7,8,9,10,11。
通过减少铁 (氧) 氢氧化物或有机质的矿化作用, 细菌活动就能影响吸附于 (氧) 氢氧化物或有机物的污水附加费的命运。用细菌直接还原铁是硫磺枯竭区铁还原的主要途径12,13, fe (iii) 被用作终端电子受体, 而间接地, fe (iii) 可由硫化物还原为 fe (II)由细菌硫酸盐减少14形成。此外, 硫酸盐的存在也可以通过形成络合物, 如硫代砷15以汞或 metacinnabar 的形式来改变 hg 和形态。
因此, 更好地了解铁和硫酸盐循环对汞的命运的影响, 如 Hg 和 as, 可以帮助我们更好地管理受污染的场址和保持土壤和水的质量。数据也有助于加强现有的金属流动模型。微生物 Fe (III)-减少16,17,18可导致 TE 的解吸。从理论上讲, 通过微生物还原硫酸盐产生的硫化物间接还原铁 (氧), 也会影响 TE 的流动性。但是, 这些反应的程度和动力学一般都是在批同质系统或批缩影16、18、19、20中进行研究的。间歇实验的缺点是缺乏对发生现象的分离;事实上, 活动是基于和有限的资源存在于批中, 只给出最后的结果的转变的形态和吸附。使用列方法可以更新流入媒体, 并监视时间和空间上的 TE 的命运。与含水层相比, 这些条件更切合实际, 那里的实际现象与连续的渗流条件密切相关。此外, 非均质铁 (氧) 氢氧化物发生在含水层沉积是共同的21,23, 并且固相矿物和化学成分的空间变化肯定会推动微生物活动.
为了阐明这些质对地质微生物现象的影响和与铁相关的 TE 的命运, 我们开发了一个实验室, 一个连续哺养的专栏代表一个简化的模型含水层。柱子被填装在专栏入口创造一个铁枯竭的区域和一个富铁的区域在顶端。定期取样端口使我们能够单独研究每个区域以及与接口相关的现象。这个实验装置的应用的例子为研究 Hg 命运和形态学已经是可利用的24。在这里, 我们给出了实验设置的详细描述和第二个例子, 其应用的重点是在受污染的含水层的行为。

<table><tbody><tr><td>Glass columns</td><td>Beaucaverre, France</td><td>Specific request</td><td>columns were composed of 3 separate pieces, the main column core with the cooling jacket and the 5 sampling ports (size GL14 with olive) and a top and bottom piece that fits to the main column body and is held in place with a silicone joint and screw (RIN F 40x38 &amp;amp; SVL 42). note: this design was discussed directly with the company. We recommend to find a local glazier.</td></tr><tr><td>Septa PTFE/silicone diameter 20 mm</td><td>Sigma-Aldrich</td><td>508608</td><td></td></tr><tr><td>PTFE tubing ID 3 mm</td><td>VWR</td><td>228-0745</td><td></td></tr><tr><td>Peristaltic pump</td><td>Dominique Dutsher SAS</td><td>66493</td><td></td></tr><tr><td>Peristaltic pump tubing LMT 55</td><td>VWR</td><td>224-2250</td><td>Tygon&amp;reg; LMT 55&amp;nbsp;</td></tr><tr><td>Fontainbleau sand D50=209 &amp;micro;m</td><td>SIBELCO, France</td><td></td><td></td></tr><tr><td>N&lt;sub&gt;2&lt;/sub&gt; for bubbling</td><td>Air Liquide, France</td><td></td><td></td></tr><tr><td>Gamma irradiation</td><td>Ionisos, Dagneux, France</td><td></td><td></td></tr><tr><td>Automatic Mercury Analyzer (AMA 254)</td><td>Courtage Analyses, France</td><td></td><td></td></tr><tr><td>Varian SpectrAA 300 Zeeman</td><td>Agilent</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Chemicals&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>HNO&lt;sub&gt;3&lt;/sub&gt; Supra pur</td><td>VWR</td><td>1.00441.1000</td><td>Manufacturer: Merck</td></tr><tr><td>HCL 30% Supra pur</td><td>VWR</td><td>1.00318.1000</td><td>Manufacturer: Merck</td></tr><tr><td>Hg(NO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;</td><td>Merck</td><td>516953</td><td></td></tr><tr><td>As&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;</td><td>Merck</td><td>202673</td><td></td></tr><tr><td>FeCl&lt;sub&gt;3&lt;/sub&gt;-6H2O</td><td>Merck</td><td>207926</td><td></td></tr><tr><td>silica gel</td><td>Sigma-Aldrich</td><td>336815-500G</td><td></td></tr></tbody></table>

experimental column setup for studying anaerobic biogeochemical interactions between iron (oxy)hydroxides, trace elements, and bacteria

含水层中的砷 (as) 和汞 (汞) 等微量元素的命运和形态与物理化学条件密切相关, 如氧化还原电位 (Eh) 和 pH 值, 但也与可直接或间接作用于生物的微生物活动有关形态和/或移动性。的确, 有些细菌可以直接氧化为 (iii) 至 as (v) 或减少为 (v) 至 as (iii)。同样, 细菌也强烈参与汞循环, 无论是通过其甲基化, 形成神经毒素单汞, 或通过其还原为元素 Hg°。砷和汞的命运也与土壤或含水层组成密切相关;事实上, 砷和汞可以结合到有机化合物或 (氧) 氢氧化物, 这将影响它们的流动性。反过来, 细菌活动, 如铁 (氧) 氢氧化还原或有机质矿化可以间接影响和汞螯合物。硫酸盐/硫化物的存在也能强烈地影响这些特定的元素, 通过形成诸如硫砷与砷或 metacinnabar 与汞的配合物。
因此, 人们对环境中砷和汞的命运和形态以及如何限制它们的毒性提出了许多重要的问题。然而, 由于它们对含水层组分的反应性, 很难明确地将发生的生物地球化学过程和它们对这些物质的命运的不同影响区分开来。
为了做到这一点, 我们开发了一个原始的, 实验的, 列的设置, 模拟一个含水层与砷或 Hg 氧化铁丰富的地区与铁耗尽地区, 使更好地了解 TE 地球化学在缺氧条件。以下协议给列设置的一步一步指示为作为或 Hg, 并且一个例子与一样在铁和硫酸盐减少的情况之下。

示例1。铁的减少对流动性和形态的影响
as 柱是直接接种与地下水从一个网站呈现的浓度高于饮用水标准 (Bracieux, 卢瓦尔等雪儿, 法国)。在无菌瓶中抽取地下水, 贮存在5° c 直至使用。这一列是从底部喂养的水中含有天然内源性微生物群落在低流速率 (2 毫升 h-1), 以促进细菌附着在沙子上。温度最初固定在25...

Watch this Scientific Journal Video about Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron OxyHydroxides, Trace Elements, and Bacteria at JoVE.com

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron OxyHydroxides, Trace Elements, and Bacteria

含水层中砷和汞的命运和形态与生理-化学条件和微生物活动密切相关。在这里, 我们提出了一个原始的实验柱设置, 模拟一个含水层, 并使更好地了解在缺氧条件下的痕量元素地球化学。结合地球化学和微生物方法, 提出了两个实例。

用于研究铁 (氧) 氢氧化物、微量元素和细菌之间厌氧生物地球化学相互作用的实验柱装置

Fate and speciation of trace elements (TEs), such as arsenic (As) and mercury (Hg), in aquifers are closely related to physio-chemical conditions, such as ...

experimental-column-setup-for-studying-anaerobic-biogeochemical

Universidad de Cartagena UDEC

Research

JoVE Journal

Environment

Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria

7.8K 次观看.  BRGM. 含水层中砷和汞的命运和形态与生理-化学条件和微生物活动密切相关。在这里, 我们提出了一个原始的实验柱设置, 模拟一个含水层, 并使更好地了解在缺氧条件下的痕量元素地球化学。结合地球化学和微生物方法, 提出了两个实例。

视频: Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron OxyHydroxides, Trace Elements, and Bacteria

Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling from hydrothermal sources in the Precambrian ocean was oxidized by molecular oxygen [O2] produced by cyanobacteria. The oldest BIFs, deposited prior to the Great Oxidation Event (GOE) at about 2.4 billion years (Gy) ago, could have formed by direct oxidation of Fe(II) by anoxygenic photoferrotrophs under anoxic conditions. As a method for testing the geochemical and mineralogical patterns that develop under different biological scenarios, we designed a 40 cm long vertical flow-through column to simulate an anoxic Fe(II)-rich marine upwelling system representative of an ancient ocean on a lab scale. The cylinder was packed with a porous glass bead matrix to stabilize the geochemical gradients, and liquid samples for iron quantification could be taken throughout the water column. Dissolved oxygen was detected non-invasively via optodes from the outside. Results from biotic experiments that involved upwelling fluxes of Fe(II) from the bottom, a distinct light gradient from top, and cyanobacteria present in the water column, show clear evidence for the formation of Fe(III) mineral precipitates and development of a chemocline between Fe(II) and O2. This column allows us to test hypotheses for the formation of the BIFs by culturing cyanobacteria (and in the future photoferrotrophs) under simulated marine Precambrian conditions. Furthermore we hypothesize that our column concept allows for the simulation of various chemical and physical environments &#8212; including shallow marine or lacustrine sediments.

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

We simulated a Precambrian ferruginous marine upwelling system in a lab-scale vertical flow-through column. The goal was to understand how geochemical profiles of O2 and Fe(II) evolve as cyanobacteria produce O2. The results show the establishment of a chemocline due to Fe(II) oxidation by photosynthetically produced O2.

一个铁（II）的实验室模拟的前寒武纪富海洋上升流系统探索光合细菌生长

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

科研

环境科学

Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations

Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled Earth-system processes. Such knowledge is imperative in improving predictions of hydro-biogeochemical cycles, especially under climate change scenarios. We present an experimental method, designed to capture sub-surface heterogeneity of an initially homogeneous soil system. This method is based on destructive sampling of a soil lysimeter designed to simulate a small-scale hillslope. A weighing lysimeter of one cubic meter capacity was divided into sections (voxels) and was excavated layer-by-layer, with sub samples being collected from each voxel. The excavation procedure was aimed at detecting the incipient heterogeneity of the system by focusing on the spatial assessment of hydrological, geochemical, and microbiological properties of the soil. Representative results of a few physicochemical variables tested show the development of heterogeneity. Additional work to test interactions between hydrological, geochemical, and microbiological signatures is planned to interpret the observed patterns. Our study also demonstrates the possibility of carrying out similar excavations in order to observe and quantify different aspects of soil-development under varying environmental conditions and scale.

This study presents an excavation method for investigating subsurface hydrological, geochemical, and microbiological heterogeneity of a soil lysimeter. The lysimeter simulates an artificial hillslope which was initially under homogeneous condition and had been subjected to approximately 5,000 mm of water over eight cycles of irrigation in an 18-month period.

土壤蒸渗仪开挖加之水文，地球化学和微生物调查

Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled ...

Self-standing Electrochemical Set-up to Enrich Anode-respiring Bacteria On-site

Anaerobic respiration coupled with electron transport to insoluble minerals (referred to as extracellular electron transport [EET]) is thought to be critical for microbial energy production and persistence in many subsurface environments, especially those lacking soluble terminal electron acceptors. While EET-capable microbes have been successfully isolated from various environments, the diversity of bacteria capable of EET is still poorly understood, especially in difficult-to-sample, low energy or extreme environments, such as many subsurface ecosystems. Here, we describe an on-site electrochemical system to enrich EET-capable bacteria using an anode as a respiratory terminal electron acceptor. This anode is connected&#160;to a cathode capable of&#160;catalyzing abiotic oxygen reduction. Comparing this approach with electrocultivation methods that use a potentiostat for poising the electrode potential, the two-electrode system does not require an external power source. We present an example of our on-site enrichment utilized in an alkaline pond at the Cedars, a terrestrial serpentinization site in Northern California. Prior attempts to cultivate mineral reducing bacteria were unsuccessful, which is likely due to the low-biomass nature of this site and/or the low relative abundance of metal reducing microbes. Prior to implementing our two-electrode enrichment, we measured the vertical profile of dissolved oxygen concentration. This allowed us to place the carbon felt anode and platinum-electroplated carbon felt cathode at depths that would support anaerobic and aerobic processes, respectively. Following on-site incubation, we further enriched the anodic electrode in the laboratory and confirmed&#160;a distinct microbial community compared to the surface-attached or biofilm communities normally observed at the Cedars. This enrichment subsequently led to the isolation of the first electrogenic microbe from the Cedars. This method of on-site microbial enrichment has the potential to greatly enhance the isolation of EET-capable bacteria from low biomass or difficult to sample habitats.

On-site microbial enrichment or in situ cultivation techniques can facilitate the isolation of difficult-to-culture microbial taxa, especially from low-biomass or geochemically extreme environments. Here, we describe an electrochemical set-up without using an external power source to enrich microbial strains that are capable of extracellular electron transport (EET).

自立电化学建立富集阳极 respiring 菌现场

Anaerobic respiration coupled with electron transport to insoluble minerals (referred to as extracellular electron transport [EET]) is thought to be ...

An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the deep ocean. Roles of minerals are critical in many hydrothermal organic geochemical processes. Traditional hydrothermal methodology, which includes using reactors made of gold, titanium, platinum, or stainless-steel, is usually associated with the high cost or undesired metal catalytic effects. Recently, there is a growing tendency for using the cost-effective and inert quartz or fused silica glass tubes in hydrothermal experiments. Here, we provide a protocol for carrying out organic-mineral hydrothermal experiments in silica tubes, and we describe the essential steps in the sample preparation, experimental setup, products separation, and quantitative analysis. We also demonstrate an experiment using a model organic compound, nitrobenzene, to show the effect of an iron-containing mineral, magnetite, on its degradation under a specific hydrothermal condition. This technique can be applied to study complex organic-mineral hydrothermal interactions in a relatively simple laboratory system.

Earth-abundant minerals play important roles in the natural hydrothermal systems. Here, we describe a reliable and cost-effective method for the experimental investigation of organic-mineral interactions under hydrothermal conditions.

研究矿物对有机热液转化影响的实验协议

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the ...

Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the emergence of life. The growth of hydrothermal chimneys in a thermal gradient environment within an early Earth vent system was successfully simulated by using different hydrothermal simulants, such as sodium sulfide, which were injected into an early Earth ocean simulant containing dissolved ferrous iron. Moreover, an apparatus was developed to sufficiently cool the ocean simulant to near 0 &#176;C in a condenser vessel immersed in a cold water bath while injecting a sulfide solution at hot to room temperatures, effectively creating an artificial chimney structure in a temperature gradient environment over a period of a few hours. Such experiments with different chemistries and variable temperature&#160;gradients resulted in a variety of morphologies in the chimney structure. The use of ocean and hydrothermal fluid simulants at room temperature resulted in vertical chimneys, whereas the combination of a hot hydrothermal fluid and cold ocean simulant inhibited the formation of robust chimney structures. The customizable 3D printed condenser created for this study acts as a jacketed reaction vessel that can be easily modified and used by different researchers. It will allow the careful control of injection rate and chemical composition of vent and ocean simulants, which should help accurately simulate prebiotic reactions in chimney systems with thermal gradients similar to those of natural systems.

The goal of this protocol is to form simulated hydrothermal chimneys via chemical garden injection experiments and introduce a thermal gradient across the inorganic precipitate membrane, using a 3D printable condenser that can be reproduced for educational purposes.

热梯度环境中早期地球热液烟囱的模拟

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the ...

Medium Preparation for the Cultivation of Microorganisms under Strictly Anaerobic/Anoxic Conditions

In contrast to aerobic organisms, strictly anaerobic microorganisms require the absence of oxygen and usually a low redox potential to initiate growth. As oxygen is ubiquitous in air, retaining O2-free conditions during all steps of cultivation is challenging but a prerequisite for anaerobic culturing. The protocol presented here demonstrates the successful cultivation of an anaerobic mixed culture derived from a biogas plant using a simple and inexpensive method. A precise description of the entire anoxic culturing process is given including media preparation, filling of cultivation flasks, supplementation with redox indicator and reducing agents to provide low redox potentials as well as exchanging the headspace to keep media free from oxygen. Furthermore, a detailed overview of aseptically inoculating gas tight serum flasks (by using sterile syringes and needles) and suitable incubation conditions is provided. The present protocol further deals with gas and liquid sampling for subsequent analyses regarding gas composition and volatile fatty acid concentrations using gas chromatography (GC) and high performance liquid chromatography (HPLC), respectively, and the calculation of biogas and methane yield considering the ideal gas law.

As obligate anaerobic organisms are unable to grow upon oxygen exposure, the use of anaerobic culturing techniques is indispensable. Here, we demonstrate a simple and effective method to cultivate a mixed culture derived from a biogas plant from media preparation to gas and volatile fatty acid quantification.

严格厌氧/缺氧条件下微生物培养的介质制备

In contrast to aerobic organisms, strictly anaerobic microorganisms require the absence of oxygen and usually a low redox potential to initiate growth. As ...

生物化学

Dissolved Solute Sampling Across an Oxic-Anoxic Soil-Water Interface Using Microdialysis Profilers

Biogeochemical processes shift rapidly in both spatial (millimeter scale) and temporal (hour scale to day scale) dimensions at the oxic-anoxic interface in response to disturbances. Deciphering the rapid biogeochemical changes requires in situ, minimally invasive tools with high spatial and temporal sampling resolution. However, the available passive sampling devices are not very useful in many cases either due to their disposable nature or the complexity and extensive workload for sample preparation.
To address this problem, a microdialysis profiler with 33 individual polyethersulfone nanomembrane tubes (semipermeable, &#60;20 nm pore size) integrated into the one-dimensional skeleton (60 mm) was established to iteratively sample the dissolved compounds in porewater across the soil-water interface at a high resolution of 1.8 mm (outer diameter plus one spacing, i.e., 0.1 mm between probes). The sampling mechanism is based on the principle of concentration gradient diffusion. The automatic loading of degassed water allows minimal disturbance to the chemical species across the oxic-anoxic interface.
This paper describes the procedures of device setup and continuous porewater sampling across the soil-water interface on a daily basis. Concentration-depth profiles were selectively measured before (on Day 6) and after (on Day 7) disturbances induced by irrigation. The results showed that concentration-depth profiles were undergoing rapid changes, especially for redox-sensitive elements (i.e., iron and arsenic). These protocols can help investigate the biogeochemical responses across the soil-water interface under various disturbances caused by physical, chemical, and biological factors. The paper thoroughly discusses the advantages and disadvantages of this method for potential use in the environmental sciences.

A microdialysis profiler is described to sample dissolved porewater solutes across an oxic-anoxic soil-water interface in situ with minimal disturbance. This device is designed to capture rapid changes in concentration-depth profiles induced by disturbances at the soil-water interface and beyond.

使用微透析剖面仪在氧化-缺氧土壤-水界面上进行溶解溶质采样

Biogeochemical processes shift rapidly in both spatial (millimeter scale) and temporal (hour scale to day scale) dimensions at the oxic-anoxic interface ...

用于培养环境微生物的原位模拟厌氧方法

A Set of In Situ Informed Simulated Medium Formats for Culturing Environmentally Acquired Anaerobic Microorganisms

Culture-dependent research of anaerobic microorganisms rests upon methodological competence. These methods must create and maintain suitable growth conditions (e.g., pH and carbon sources) for anaerobic microorganisms while also allowing samples to be extracted without compromising the artificial environment. To this end, methods that are informed by and simulate an in situ environment can be of great aid in culturing microorganisms from that environment. Here, we outline an in situ informed and simulated anaerobic method for culturing terrestrial surface and subsurface microorganisms, emphasizing anaerobic sample collection with minimal perturbation. This protocol details the production of a customizable anaerobic liquid medium, and the environmental&#160;acquisition and in vitro growth of anaerobic microorganisms. The protocol also covers critical components of an anaerobic bioreactor used for environmental simulations of sediment and anaerobic liquid media for environmentally acquired cultures. We have included preliminary Next Generation Sequencing data from a maintained microbiome over the lifespan of a bioreactor where the active culture dynamically adjusted in response to an experimental carbon source.

作者聚焦:通过原位培养揭开未知环境中陆地厌氧微生物的神秘面纱

The focus of this paper is to detail best practices for making media for fastidious anaerobic microorganisms acquired from an environment. These methods help manage anaerobic cultures and can be applied to support the growth of elusive uncultured microorganisms, the "microbial dark matter."

一套用于培养环境获得性厌氧微生物的 原位 信息模拟培养基格式

Culture-dependent research of anaerobic microorganisms rests upon methodological competence. These methods must create and maintain suitable growth ...

用于研究铁 (氧) 氢氧化物、微量元素和细菌之间厌氧生物地球化学相互作用的实验柱装置

摘要

探索更多视频

此视频中的章节

一个铁（II）的实验室模拟的前寒武纪富海洋上升流系统探索光合细菌生长

土壤蒸渗仪开挖加之水文，地球化学和微生物调查

自立电化学建立富集阳极 respiring 菌现场

研究矿物对有机热液转化影响的实验协议

热梯度环境中早期地球热液烟囱的模拟

严格厌氧/缺氧条件下微生物培养的介质制备

使用微透析剖面仪在氧化-缺氧土壤-水界面上进行溶解溶质采样

一套用于培养环境获得性厌氧微生物的原位信息模拟培养基格式

一套用于培养环境获得性厌氧微生物的原位信息模拟培养基格式

一套用于培养环境获得性厌氧微生物的原位信息模拟培养基格式

用于研究铁 (氧) 氢氧化物、微量元素和细菌之间厌氧生物地球化学相互作用的实验柱装置

摘要

探索更多视频

此视频中的章节

一个铁（II）的实验室模拟的前寒武纪富海洋上升流系统探索光合细菌生长

土壤蒸渗仪开挖加之水文，地球化学和微生物调查

自立电化学建立富集阳极 respiring 菌现场

研究矿物对有机热液转化影响的实验协议

热梯度环境中早期地球热液烟囱的模拟

严格厌氧/缺氧条件下微生物培养的介质制备

使用微透析剖面仪在氧化-缺氧土壤-水界面上进行溶解溶质采样

一套用于培养环境获得性厌氧微生物的 原位 信息模拟培养基格式

一套用于培养环境获得性厌氧微生物的 原位 信息模拟培养基格式

一套用于培养环境获得性厌氧微生物的 原位 信息模拟培养基格式

一套用于培养环境获得性厌氧微生物的原位信息模拟培养基格式

一套用于培养环境获得性厌氧微生物的原位信息模拟培养基格式

一套用于培养环境获得性厌氧微生物的原位信息模拟培养基格式