Name: measuring carbon-based contaminant mineralization using combined co2 flux and radiocarbon analyses
Uploaded: 2016-10-21T12:30:00.000+00:00
Duration: 11 min 19 s
Description: Watch this Scientific Journal Video about Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses at JoVE.com

Financial support for this research was provided by the Strategic Environmental Research and Development Program (SERDP ER-2338; Andrea Leeson, Program Manager). Michael Pound, Naval Facilities Engineering Command, Southwest provided logistical and site support for the project. Brian White, Erika Thompson and Richard Wong (CBI Federal Services, Inc) provided on-site logistical support, historical site perspective and relevant reports. Todd Wiedemeier (T.H. Wiedemeier &amp; Associates) provided documentation, discussion and historical site perspectives.

1.准备和现场安装<ol><li>购置必要的实地设备;水泵，电动（电池，太阳能电池，变压器等 ），油管，以及帽，配件，样品瓶和瓶，探头（pH值，嗯， 等 ）和低压泵。 </li><li>密封电池供电的空气泵。钻一个孔进入泵壳体（尺寸53）和塑料的不透气管材"1/16的路线一小段（3-5）"（例如PFA）。 <ol><li>密封泵（围绕下橡胶壳体）与海洋密封剂随后硅酮密封剂的涂层的所有外部部分。 </li><li>压力通过在外壳管轻轻地吹而阻断流出测试泵。检查泄漏视觉。 注:光压力应持有，如果没有漏气（ 图1）。 </li></ol></li><li>安装监测井（如有必要，在这项研究中现有油井中使用-筛选整个渗流:地下水接口）18 </SUP&gt;。 注意:一个好必须是一个很好的背景中的位置代表污染场地的 - 但没有已知的石油污染。 </li><li>获得初步的地下水模型的数据，如果他们不存在（导水率，含水层孔隙度，土壤密度，比产量，水力坡度等 ）所描述的18。使用此数据来制定的影响（ 二氧化碳捕集区的估计）一区（ZOI）模型。作为补充材料18中所述准备ZOI模式。 </li><li>由〜25克NaOH和转让称量到100ml的血清瓶中制备的 CO 2陷阱。盖上血清瓶用隔膜和紧紧压接。准备一个陷阱为每个集合井（ 图2），外加一个领域的空白。 </li><li>如需要获得初始pH值，溶解无机碳（DIC）的浓度和阳离子浓度10,18进行初步的地下水取样。填写取40ml挥发或加尼奇分析（VOA）小瓶中，从底部到凸弯月面与地下水（经由水瓢样品，蠕动泵或真空线）中，添加饱和硫酸铜溶液19 5滴，盖紧瓶盖（必须使用隔膜帽）用尽可能少顶部空间尽可能。 <ol><li>就拿其他分析额外的小瓶（污染物浓度，例如）。如果仪表不现场提供用于pH测量的不含防腐剂的小瓶。冷藏和运输到实验室。 </li></ol></li><li>路由电力线（能进行约1放）沿着地面或其它方便的装置到各孔。贴上修改泵（见1.2），并确保泵工作正常（应该能听到它的工作）。 注:该泵可容纳12 V，但使用较低的电压，以节省功率（ 图3）。 </li><li>盖井用改良的气密性好帽。 <ol><li>为了为了准备通过帽帽，钻两个孔（钻孔尺寸53），紧密贴合1/16"气行。通过盖线路二气行。 </li><li>拉一条线，使得它停留在接近地下水表 （ 图4）。贴上就结束了沉重的不锈钢螺母，以权衡下来就行了。 </li><li>路线其它线正好在盖下方（这将是气体返回线）。外套密封面和线程拥有充足的真空脂来抑制任何的空气交换。拧紧瓶盖好。 </li><li>路线下管导入泵入口。路线从泵到使用＃16号针头穿过隔膜的CO 2捕集氢氧化钠（NaOH）的气体线。路线从陷阱返回行（使用第二＃16针）只盖下方结束的天然气管线。 </li><li>由供电启动泵和收集至少30孔体积（这取决于井顶部空间的体积，它可以与井半径（r）和估计的距离来地下水位（L）来计算， 即 πR2升）。丢弃最初的陷阱（清除顶部空间）。 </li><li>删除并从每个瓶的隔拔出针头，并把他们在新瓶的隔收集实验的 CO 2之前，用新鲜的陷阱代替。注意泵开启时间和日期。 </li></ol></li></ol> 2.初始样品分析<ol><li>要通过库仑20测量DIC: <ol><li>转让一式三份1毫升子样本与隔封顶40毫升血清瓶。酸化用1ml 80％ 的 H 3 PO 4子样本。喷射用的 CO 2 -free空气流。 </li><li>干与顺序镁（CLO 4）2和硅胶（230-400目，60）陷阱线演进的 CO 2气体流和擦洗。气泡的气体流引入其中比色测定法来量化的 CO 2库仑细胞。使用有证标准物质校准测量21。 </li></ol></li><li>测量pH值使用标准校准的pH计。测量pH现场或保存的样品。 </li><li>通过测量离子色谱法溶解阳离子: <ol><li>吸取5毫升无防腐剂地下水样品自动进样瓶。帽小瓶中并发生在耦合到离子色谱自动取样器。 </li><li>使用特定阳离子列分析10,18。使用20mM的甲磺酸作为洗脱液和色谱流量设为〜0.7毫升分钟-1。 </li><li>稀的6阳离子标准（含有镁，钙，钠，和钾作为最低）0.5的储备溶液:使用纯化水1:4.5，1:4,2:3,3:2和4。运行这些标准在分析的开始和每25未知样品之后。运行每个样品三次（一式三份）。创建通过绘制阳离子浓度对峰面积，并产生一个线性回归的标准曲线。据此分析领域10,18样本。 </li></ol></li></ol> 3.测量二氧化碳的生产ð矿化速率现场<ol><li>经过约两周到两个月（会有所不同很可能是从现场原位微生物代谢率的基础上的网站），拔掉他们切断电源到泵。 <ol><li>对于再循环气体陷阱，取出针，并用"新鲜"CO 2捕集更换。如果密封（ 参见 图3）的陷阱是用于长期储存是稳定的。 </li></ol></li><li>当准备用于分析，溶解任何残留的未用（固体）NaOH和整个液体内容传输到一个容积装置以获得稀释体积。确定全卷（例如200毫升剩余的氢氧化钠充分溶解）和转让子样（5-10毫升）到40毫升的小瓶隔。 <ol><li>通过注入50％（V / V）磷酸，喷射酸化和分析由库仑所得气流（见2.1）。 </li><li>通过缩放子样本到整个volum手动计算二氧化碳收集率e和收集到的时间（ 即X每天克Co 2）。减去领域的空白CO 2含量。例如，如果完全溶解的氢氧化钠为200毫升，以20乘10ml的子样本以反映总的 CO 2的浓度。 注意:如果该样本代表收集的14天，收集率将是缩放的CO 2浓度14天划分。暗算初始浓度DIC CO 2的收集率。如果不存在相关性，收集率是不均衡动力学的唯一功能。 </li><li>为了考虑平衡动力学，人工采样期间减去所有其他的井的收集率最低的收缴率。 注意:例如，如果最低的收集率为0.0001毫克ð-1，进行保守的假设，这代表只平衡收集和减去该值对于所有其它的收集率，以获得第ËCO 2的生产速度，由于降解。缩放率是有机碳矿化率（保守的最低利率可能包括一些污染物矿化）。 </li></ol></li><li>通过加速器质谱（AMS）分析了剩余的CO 2，以确定放射性碳含量22。使用大约1毫克的碳此分析。缩放收集时间（s）收集足够的 CO 2。减去在现场通过质量平衡（放射性碳测量领域的空白缩放到的CO 2）空白的放射性碳含量。 注:所描述的试验场地，2周藏品被绰绰有余获得1毫克的碳。 </li></ol> 4.模式影响的区域，以估计取样的 CO 2的卷土<ol><li>通过ModelMuse接口25使用MT3DMS 23加上MODFLOW-2005 24模拟二氧化碳的扩散和平衡与井屏幕（视频1）有关。该模型的分辨率为0.09米0.09米它近似等于所述孔的横截面，并认为合理的ZOI估计。 <ol><li>下载并安装MODFLOW-2005（http://water.usgs.gov/ogw/modflow/MODFLOW.html#downloads），MT3DMS（http://hydro.geo.ua.edu/mt3d/）和ModelMuse（HTTP ://water.usgs.gov/nrp/gwsoftware/ModelMuse/ModelMuse.html）。 </li><li>与MODFLOW程序位置配置ModelMuse。要做到这一点，单击"模型"菜单，然后选择"MOFLOW程序位置..."，然后点程序到MODFLOW-2005程序的安装目录:/bin/mf2005.exe。在此同一对话框中，用MT3DMS程序位置（:/bin/mt3dms5b.exe安装目录）配置ModelMuse。 </li><li>配置MODFLOW软件包和程序（在ModelMuse内）。要做到这一点，选择"模型"菜单，然后选择"MODFLOW软件包和程序......"。在"流"，选择LPF:4，层属性流程包"。 </li><li>在"边界条件"，选择"指定头"，然后选择CHD:时变指定-头包"，选择"MT3DMS"选择"BTN:。"基本运输包装将移动物种CO 2。 </li><li>配置中ModelMuse MODFLOW选项。要做到这一点，选择"模型"菜单，然后选择MODFLOW。在"选项"选项卡，设置示范单位（米，小时，克（克））。 </li><li>通过选择"模型"菜单，然后配置MODFLOW时间"MODFLOW时间"。使用360长度应激期将有15天的模拟运行。 </li><li>配置MODFLOW数据集选择"数据"菜单，选择"数据集"。从关注点中输入数据:水文（3维的K值，初始MODFLOW头，Modflow的指定负责人）; MT3DMS:（扩散系数的 CO 2，初始浓度的 CO 2，纵向弥散性）。 </li><li> ËDIT全局变量。选择"数据"菜单，选择"全局变量"。进入CO 2的收集率（从网站）和初始CO 2浓度。 </li><li>运行模拟。按下顶部的图标栏上的绿色箭头开始模拟。提示时保存输入文件。模拟运行。运行后，出口MT3DMS输入文件:选择"文件"菜单，然后选择"导出"，然后MT3DMS输入文件。模拟编译和导出数据。 </li><li>观察并输出模型结果。点击图标栏上的可视化图标。选择模拟。在X，Y，Z轴输出ZOI边界值 注:此模式代表了二氧化碳收集影响的区域（整个模型开发以报告的形式从支撑材料描述可用）18。的ZOI，其被定义为含水层的体积已经达到95％或更低的CO 2浓度，似乎是对称的水力梯度这表明与小水力梯度旱季平流过程的影响相对较小。进一步的分析表明，含水层的任何CO 2耗尽的体积（ 即 ，&lt;99％）显著较长扩展区下坡。 </li></ol></li></ol> 5.夫妇放射性碳含量的CO 2的生产速度和规模，以卷（带ZOI） <ol><li>转换放射性碳年代（如有必要），以每使用标准公式22密耳符号。在方程使用的背景以及放射性碳值作为一个已知的（Δ14 C- NOM）（1）。 Δ14 C- 石油是知道（-1000）。使用了Δ14单井值的 CO 2。解决部分石油 。 （1）Δ14 CO 2 =（Δ14 C- 石油 -X 部分 石油 ）+ [Δ14 C- NOM×（1 - 分数石油 ）] </li><li>由二氧化碳矿化率（3.1）乘以部分石油，以确定污染物矿化率（ 即 50％×1.0毫克Ð-1 = 0.5毫克的碳污染物Ð-1）。 </li><li>通过在计算出的ZOI体积除以污染物矿化速率（4）确定每单位体积（ 即，0.05毫克C M -3ð-1）的每单位时间的污染物质量矿化。 </li></ol>

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The authors declare that they have no competing financial interests

一种协议，描述了旨在速率测量，比例矿化污染物（S）和ZOI共同决定整个网站的污染物降解。关键组件，测量二氧化碳的生产（修正时矿化）随着时间的推移，同时收集呼出的二氧化碳数量充足（〜1毫克）为AMS放射性碳分析提供从污染物降解派生量，并创造了ZOI模型关系所捕获的 CO 2土壤或地下水（或两者）的已知体积。这三个主要成分结合在一个整体的计算在每个采样点用于污染物每单位时间单位体积降解的量到达（克-3ð-1，例如）。缩放计算，经过反复和地理上分开测量（井子采样覆盖在更长的时间尺度的网站），将允许网站管理员估计空间和tempor人的降解动态和适当的应对监管机构和利益相关者。 所描述的协议使用再循环泵或长期部署被动采样（目前正在开发的策略），以从井顶空气阱出来的 CO 2。究其原因是几折。首先，充分的 CO 2必须以获得放射性碳测量（〜1毫克）被收集。呼吸速率可以用表层土壤测量:空气交换的陷阱，或通过土壤呼吸仪器（例如LICOR通量室）。这些方法从需要遭受异步收集到足够的 CO 2放射性碳分析-因此也许偏置测量。例如，焊剂室可配备测量土壤:空气中的 CO 2交换，而占大气CO 2 17涌入。除非呼吸率很高，充足的 CO 2放射性碳测量不得截留。在这种情况下，样品可从大型土壤气体样品或地下水（与DIC）12所。此外，测量的 CO 2通量在土壤:空气表面受到从大气侧到通量室或陷阱涌入。采样以及顶空"隔离"的信号到污染的区域（取决于井安装在一定程度上），但适当地选自大气流入（和大气产生现代14 CO 2）的除去。主要的困难是从井采样，而无需为了改变陷阱（为时间采样），以将其打开。 使用再循环泵允许一个样品井顶部空间并改变二氧化碳的陷阱定期而不必暴露样品位置到大气14 的 CO 2。它也允许一个采样相当的 CO 2然后可以对通量和天然放射性碳含量进行分析。再循环公关otocol并非没有困难。一个主要的问题是提供充足的动力在现场连续运行泵。为初始实验（这里描述的），太阳能电池板提供了足够的能量来运行对每两个星期内泵。电压记录显示，几天后，太阳能发电无法与所需的功率跟不上，每天泵不运作了几个小时。这是无关紧要的光通量建模和全面收集，但更强调提供充足的动力进行实地部署的硬件的难度。在当前运行的集合，动力泵已被地勤人员在监控井场割草中断。几个电源线都被切断。我们目前正在评估顶空部署无源CO 2陷阱可能具有吸收的 CO 2被降低到井和检索在稍后的日期。风险 - 效益分析正在进行中（大部分来自不必打开井口，让大气中产生的风险14 CO 2）。 该技术的主要限制是不能够区分在混合污染物的系统的准确呼吸源和不能够占中间碳基降解产物（ 即 ，DCE，VC，甲烷）。举例来说，在目前的网站，有除CH污染历史燃料碳氢化合物污染。簇头几乎完全从石油原料制成。在描述现场，CH是在所研究的区域主要是孤立的 - 而一些残留的石油显然存在北。没有石油在取样这项工作井发现。然而，在混合污染物网站，整体矿化率可能难以绑在一个人或一类污染物。使用这种方法，可以量化完整CH降解（成CO 2）。如果，污染物碳被转化为CH 4（厌氧条件），CH 4的可＆＃34。丢失"，如果它漫射从ZOI远即碳可能会被转换为在渗流区好氧部分内CO 2如果这没有在ZOI内发生，所报道的方法将不考虑它在这种情况下。 ，所描述的方法可以被认为是保守的估计，从监管的角度来看，是理想的。另外，该ZOI建模也不是没有不确定性。模拟是基于它们在假定子样本测定"单数"值，例如孔隙度和堆积密度是同质 - 但在现实中是在宏观和microscales异构感知限制可以是天然丰度放射性碳分析成本（可高达每个样品$ 600）的信息的确切性质从放射性碳品牌聚集。成本在现实中非常低。随着几个精心挑选的样品中，可确定是否实质性补救正在发生。如果，例如CO 2的相关联瓦特第i污染物羽是相对于背景站点10放射性碳耗尽。与低环境pH值（&gt; 4.8〜）和可观的石灰石（ 碳酸钙 ），一个网站可能是应用这种技术的一个贫穷的候选人。古代的碳酸盐沉积在可能低pH值和偏差分析溶解。 该技术的意义是相当大的，作为唯一的测量类型（自然丰度放射性碳）可以立即使用在污染物的就地转化确认为CO 2。这种分析是决定性的。放射性碳不能成为耗尽除非通过放射性衰变 - 这是尽管物理，化学或任何原料生物改变常数。静态测量放射性碳（如DI 14 C）可以在一批样品进行并立即确认，如果14 C-耗尽CO 2是在一个网站普遍（无可辩驳地表明污染物矿化为CO 2）。这条信息单独和灰是现场管理人员因为没有它非常有价值，他们需要使用大量的证据间接行推断污染物矿化发生。没有其他的单次测量能够提供基于碳的污染物，并通过完全降解产生的含碳的 CO 2之间的具体连接。 未来的应用是目前正在进行中，我们集团将增加采样时间分辨率整整一年来涵盖。通过收集的 CO 2和确定在该网站的空间范围的矿化度（S），我们就可以在一段时间，以缩小用于污染物降解的模型。此信息至关重要，以便在需要由现场管理人员能够最有效地管理受污染场地。在有限的使用，在三个网站，该技术已被应用于监管机构已经认识到方法最终结果。这导致节约成本，并帮助指导补救阿尔特rnatives。

环境清理费用是惊人的，在美国和国外众多污染的场所。这使得创新的治疗和监测策略，以达到完全反应（RC）状态（ 例如，没有进一步的动作需要）经济至关重要。传统上，会聚证据行原位生物修复，非生物污染物转化，或其他形式的天然的衰减已经证实。证据线不能被用于绝对确认降解或原位条件1下收集的污染物的降解速率的信息。收集宽的数据来预测修复时间刻度（多个）的阵列经常被推荐的，但连接这些数据的成本有效地完全确认补救一直是个问题2-4。用尽可能少的成本尽可能获取最真实和完整的网站概念模型的数据是一个最终的现场管理的目标。此外，监管机构和stakeholDER需求代表着获得最及时的，有价值的和具有成本效益的信息额外的驱动程序。能够对污染物流失率提供了令人信服的证据的相对廉价的方法提供满足清理目标最大的价值。 由于非常独特的同位素特征是基于碳的污染物可用，碳同位素最近已应用于在野外场地5-13了解污染物的衰减过程。稳定的碳同位素可以如果源是基于瑞利蒸馏动力学（ 参见 5,6-对于评论）衰减可以用来确定。或不代表一个同位素独特的"开始"溢出（从中初始稳定碳同位素比率可以衍生） - 这种方法，而方便，可当污染物是从混合来源的限制。自然丰度放射性碳分析代表了另一种（也许是互补）同位素STrategy用于测量基于碳的污染物降解为CO 2。燃料从石油原料衍生的工业化学品将完全无c相对于当代（循环积极）的碳14，其中包含由大气中的宇宙射线的反应产生14的C。作为稳定的碳同位素分析，和14 C-衰变不显著通过物理，化学或生物过程的影响放射性碳分析不受分馏。此外，14 C信号-或缺乏-石油衍生材料在整个污染物池均匀分布使其成为一个完全混溶示踪剂。此处所描述的技术依赖于观察，虽然CO 2的来自微生物降解的NOM将含有易可测量量14℃的生成从化石来源的污染物产生的任何的 CO 2会缺乏14 C-测量14 CO 2还允许一个完全降解污染物（ 即矿化）直接链接到一个无害的最终产品。 14 CO 2的分析已被用于跟踪化石燃料衍生的污染物降解产物7-13。这是由于年底的成员（化石和现代）之间的解析解这大概是每千人（‰）1100件。通常，加速器质谱（AMS）来解决天然丰度放射性碳。大气CO 2（〜+ 200‰），活体生物量（〜+ 150‰）和土壤有机质来源的CO 2（〜-200- + 100‰）都是不同的解析来自化石来源的CO 2（-1000‰）。这是由于所有14 C，其具有的大致6000年半衰期的完全腐烂。燃料和工业化学品从石油原料，这是亿万年从活性炭去除循环派生，具有鲜明的放射性碳签名（-1000‰≈0％现代 - 这意味着对AMS无检测）。测量很简单，在样品污染方面，几乎所有潜在的偏见是对保守（与污染现代CO 2的样本）。例如， 大气中的二氧化碳进入样本会增加放射性碳同位素特征，从而导致低估降解率。 二氧化碳从化石燃料为基础的污染物降解演变将放射性碳免费。在背景的网站，没有污染， 二氧化碳呼出从天然有机物（NOM）将年龄适当的NOM。内的羽流或在边缘，污染物来源的 CO 2将具有0％现代碳。 二氧化碳从化石来源的NOM源和CO 2可以与两个端构件混合模型11区分开来。因此，有可能向埃斯蒂马忒整个CO 2的游泳池（气息奄奄碳）归属于该污染物的比例。仅仅使用这个比例，化石烃或工业化学氧化在外地的网站已被确认7-13。然后，该衍生的 CO 2污染物的比例可以配上CO 2总矿化速率（每单位时间和体积收集的所有的 CO 2），以确定本征杂质矿化速率。假设这衰减率将继续在给定的场地条件，那么可以估算需要的网站关闭的时间。 技术可用于确定土层CO与具有开放的方法或封闭系统设计14 2通量。封闭系统通量室和气体流量模型已被用于测定污染土壤12,13,15-17净呼吸。在这些研究中，空间测量直接与污染羽和backgrou相关第二方面表现出增强的有机污染物降解。各种造型方法被用来扩展垂直通量测量部位的体积。这项研究的目的是开发一种用于在使用收集率来确定污染物从呼吸大气中的二氧化碳污染（密封井）不影响收集足够的 CO 2 AMS分析（约1毫克）的方法。最后，模拟的影响（ZOI）的区域，以最终缩放测量3维（体积）允许确定每单位时间基础上的每单位体积上和氯化烃（CH）变换。的ZOI允许人们确定呼吸和放射性碳测量多少体积取自。该方法包括俘获演变的 CO 2通过NaOH阱再循环井顶部空间气体，测量所收集的 CO 2的放射性碳含量，采用了两个端构件模型来分摊收集不纯的ori的CO 2的杜松子酒，则缩放测量到通过位点特异性地下水模型计算出的体积。井顶部空间气体被再循环，以便只有均衡处理从相邻的ZOI"拉" 的 CO 2。

<table><tbody><tr><td>Air pump; Power Bubbles 12 V</td><td>Marine Metal</td><td>B-15</td><td></td></tr><tr><td>Marine Sealant</td><td>3M</td><td>5200</td><td>for sealing pumps</td></tr><tr><td>Silicone Sealant</td><td>Dap</td><td>08641</td><td>for sealing pumps</td></tr><tr><td>Tubing for gas recirculation</td><td>Mazzer</td><td>EFNPA2</td><td></td></tr><tr><td>Stopcocks (for gas lines)</td><td>Cole-Parmer</td><td>30600-09</td><td>for assembling gas lines</td></tr><tr><td>Male Luer lock fittings</td><td>Cole-Parmer</td><td>WU-45503-00</td><td>for assembling gas lines</td></tr><tr><td>Female Luer lock fittings</td><td>Cole-Parmer</td><td>EW-45500-00</td><td>for assembling gas lines</td></tr><tr><td>4&quot; Lockable J-Plug well cap</td><td>Dean Bennett Supply</td><td>NSN</td><td>2&quot; if smaller wells</td></tr><tr><td>HOBO 4-Channel Pulse Data Logger</td><td>Onset</td><td>UX120-017</td><td>Older model no longer available. Use to monitor pump operation</td></tr><tr><td>Serum bottles 100 ml (cs/144)</td><td>Fisher Scientific</td><td>33111-U</td><td>For CO&lt;sub&gt;2&lt;/sub&gt; traps</td></tr><tr><td>Septa (pk/100)</td><td>Fisher Scientific</td><td>27201</td><td>For CO&lt;sub&gt;2&lt;/sub&gt; traps</td></tr><tr><td colspan="4">&lt;strong&gt;Coulometry&lt;/strong&gt;</td></tr><tr><td>Anode solution</td><td>UIC, Inc</td><td>CM300-001</td><td></td></tr><tr><td>Cathode solution</td><td>UIC, Inc</td><td>CM300-002</td><td></td></tr><tr><td colspan="4">&lt;strong&gt;For IC analysis&lt;/strong&gt;</td></tr><tr><td>Dionex Filter Caps 5 ml 250/pk</td><td>Fisher Scientific</td><td>NC9253179</td><td>Caps for IC</td></tr><tr><td>Dionex 5 ml vials, 250/pk</td><td>Fisher Scientific</td><td>NC9253178</td><td>Vials for IC</td></tr><tr><td colspan="4">&lt;strong&gt;If using solar power&lt;/strong&gt;</td></tr><tr><td>Renogy Solar Panel kit(s)</td><td>Renogy&amp;nbsp;</td><td>KT2RNG-100D-1</td><td>Bundle provides 200 W</td></tr><tr><td>VMAX Solar Battery</td><td>VMAX</td><td>VMAX800S</td><td>For energy storage</td></tr></tbody></table>

measuring carbon-based contaminant mineralization using combined co2 flux and radiocarbon analyses

描述了一种方法，它使用不存在在从石油原料频繁污染环境取得工业化学品和燃料放射性碳的。这个放射性碳的信号-或者说没有信号-是均匀分布在整个污染物源池分布（不像一个附加示踪剂），而不是由生物，化学或物理过程（如 14 C-放射性衰变率是不可改变的）影响。如果化石来源的污染物是完全降解为CO 2，一种无害的终产物，即二氧化碳将不包含放射性碳。从天然有机物（NOM）的降解，衍生的二氧化碳将反映NOM放射性碳含量（一般&lt;3万年左右）。定为NOM（站点背景）公知的放射性碳含量，一个两个端构件混合模型可被用来确定从矿物源给定的土壤气体和地下水样品中产生的二氧化碳 。耦合在p从与CO 2的呼吸率的污染物衍生ercent CO 2提供了污染物的每单位时间劣化的总量的估计值。最后，在确定的影响表示从哪个网站的 CO 2被收集允许确定每单位时间和体积污染物降解的体积的区域（ZOI）。随着估算总污染物的质量，这最终会被用来计算时间对调整或以其他方式供决策使用的网站管理员。

在试验现场，历史CH污染已经中央以及集群（MW-25-MW-30）内，靠近谢尔曼路（ 图5）一直最高。 1983年，污染大的部分是从垃圾填埋场（试验场北部）移除，发生在2001年CH浓度额外的挖掘源去除特别是靠近前坑（谢尔曼路）后有所下降，但持久羽继续存在于中央阱簇区域。季节性降雨是众所周知的瞬时增加CH浓度和残留污染解吸的土壤27。在该地区的土壤主要是前疏通沙滩。用上述方法的一种可能的干扰可能存在，如果古碳酸盐岩都存在，地下水pH值很低（&lt;〜5）。这可能导致碳酸盐溶解并产生的CO 2的古老信号。无显著碳酸钙被称为在该地区，然而，测量并且经受回归和主成分分析（PCA）的阳离子和pH值。主要关注的是低pH值可以促进碳酸钙（ 碳酸钙 ）解散，这可能会偏向放射性碳分析（古碳酸盐岩可以溶解，如果用酸性水提供CO古代2）。 Na +的含量在现场（靠近海洋）南侧略高，但没有值分别表示显著海水入侵的范围。钙离子浓度范围为8.0〜58毫克L-1。与钙离子浓度，pH值（R 2 &lt;0.3）时，也没有说明碳酸盐溶解。 PCA双图没有表明任何变量强负荷。间以及差异也没有表明碳酸盐溶解（ 图6）。这种构象分析应该适应这一方法，以新的网站时，需要考虑的关键 - particul阿尔利那些指示显著碳酸盐岩层区域地质。 的 CO 2生产速率范围从0到34毫克的CO 2天-1。 CO 2的产量在区域中心以及集群中的污染历史最高（ 图5）中最低。 CO 2的生产以及MW-01（背景很好-没有显示，但是〜500米，主井群的西北）为31毫克的CO非常高的2天-1）。重复呼吸分析有标准误差的范围从0.03至CO 2 6％，平均小于1％（0.98）。 两个，2周的周期旱季测量值平均为后续计算。呼吸测量并没有单独的为期2周的时间之间有很大的不同。呼吸期间介于标准误差&lt;1至51％，但平均为13％（ 表1）。 Respirati在平均计算允许一个单一的CH音量在一个月内拆除。背景井（MW-01）有1280年的放射性碳年代存在（YBP）或85％的现代（PMC）之前-一个共同的范围岁土壤有机质26之内。此井的值作为背景的同位素的混合模型。再次，因为采样仅限于一个月总，两个相同的季节期间回到后端段被用来"代表"旱季 - 通常认为是最停滞条件，从而保守为外推估计。与DIC的生产速度，放射性碳测量结果个人2周的时间相似。周期之间的标准误差范围是0.25至18％，平均为6％。 CO 2的放射性碳年龄为34〜85 PMC或〜1340 8700 YBP（ 表1）。 MW-27和MW-32，疑似由水泵漏水的问题被泄露过放射性现代VAL因此，用户设备和被证实为损害。这些样品中不包括进一步的分析。 以前的报告被用于地下水液压和CO 2溶质性质开发ZOI模型26,27（ 表2）。从CIMIS圣迭戈站（站号184）气象数据（2007年，2011和2012年）被用来估计含水层补给量。在从NOAA圣迭戈站（站号:9410170），同一时间段潮汐数据被用来定义边界条件。该模型假定校准一个稳定的水力梯度和恒定的二氧化碳收集率。补充模拟不同的平均二氧化碳收集率，再加上参数化模型帮助10％的水力梯度增加初始背景的 CO 2。使用平均二氧化碳收集率A补充模拟显示，电子同比增长约46％stimated背景CO 2（ 即从6.5提高到9.5克-3），如果征收率从0.00530（+ 10％）超过2周收集期间改为0.00434克小时-1（-10％）（ 见表3） 。为ZOI模型假设包含可忽略的CO在收集期间2生产归属于CH降解和均匀的初始CO 2的分布开发最终模拟（ 图7）。 CO 2的反应速率可能被低估了研究地点。 从ZOI模型中使用二氧化碳生产速率，CO 2归属于CH退化，和估计，大众CH去除在每个单位以及时间计算。从表1的数据是用两个端员混合模型中使用（方程（1））来解决在每个F 宠好。因为网站只知道CH CON<html>污染并没有其他的 CO 2源是内部或现场附近发现，CH退化假设为主体的二氧化碳作出贡献。的F 宠物在现场（ 表4）介于1至60％。的比例被转化为碳基和乘以CO 2的生产速率来计算CH降解率（ 表4）。使用ZOI体积（ 表3），每单位时间和体积污染物降解速率测定（ 表4）。此值介于0到32毫克C M -3ð-1（ 表4）之间。 CH退化的历史最高CH污染地区最低（MW-25 - MW-30）。在靠近边缘部位（近谢尔曼路）井，最高CH降解进行了测量。 CO 2的产量为在这些区域较高，而f 涤纶指示显著CH周转（ 图8）。 NT"FO:保together.within页="1"&gt; <img alt="图1" src="/files/ftp_upload/53233/53233fig1.jpg" /> 图1. 密封，并准备循环泵。密封循环泵进行现场部署。 <img alt="图2" src="/files/ftp_upload/53233/53233fig2.jpg" /> 现场准备部署 图2. 氢氧化钠陷阱120毫升加入NaOH陷阱血清瓶和卷边密封。 <img alt="图3" src="/files/ftp_upload/53233/53233fig3.jpg" /> 图3. 现场安装。丝送到整体式井（左），陷阱部署在井（右上），以及太阳能电源分配系统（右下）。井配备在与收集系统（包括布线，配电和泵/陷阱）的字段。 ther.within页="1"&gt; <img alt="图4" src="/files/ftp_upload/53233/53233fig4.jpg" /> 图4. 修改以及瓶盖显示废气再循环线。该图显示了进气口以及修改帽子和回油管。 <img alt="图5" src="/files/ftp_upload/53233/53233fig5.jpg" /> 图5. 历史氯代烃污染（微克L-1）。该图表示在试验位点的历史氯化烃污染。 <img alt="图6" src="/files/ftp_upload/53233/53233fig6.jpg" /> 显示出溶解阳离子和pH值之间没有合作关系 图6. PCA双情节。此图显示了从测试现场水文地质资料（pH值和阳离子）创建的PCA分数和负荷的双阴谋。 内容"FO:保together.within页="1"&gt; <img alt="图7" src="/files/ftp_upload/53233/53233fig7.jpg" /> 图7.校准ZOI模型对于一般的 CO 2的收集速率（0.0048克-3）。经校准背景CO 2的浓度为6.5克-3和ZOI阈浓度为6.18克-3（黑色实线）。该ZOI的纵向和横向直径分别为2.28米和0.72微米。的ZOI的深度为0.12微米。来自18个修改。该图显示了在3个维度的ZOI模型的图形表示。 <img alt="图8" src="/files/ftp_upload/53233/53233fig8.jpg" /> 单位时间 图8. 污染物的降解率，单位面积从 18修改。这是为CH在研究站点过采样的时间段内插降解率。 视频1.使用MT3DMS23 ZOI的发展- MODFLOW模拟 （ <a href="https://ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/53233/Video_1_ZOI_simuation.mp4" target="_blank">右键点击下载</a> ）。下载，安装，初始化并为ZOI创建模拟。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td>好</td><td> δ13 C （VPDB‰） </td><td> Δ14 C- （‰） </td><td>传统时代 （YBP） </td><td>百分比现代C （PMC） </td></tr><tr><td> MW-01 </td><td> -34 </td><td> -147 </td><td> 1280 </td><td> 85 </td></tr><tr><td> MW-21 </td><td> -28 </td><td> -663 </td><td> 8730 </td><td> 34 </td></tr><tr><td> MW-25 </td><td> -23 </td><td> -153 </td><td> 1340 </td><td> 85 </td></tr><tr><td> MW-26 </td><td> -25 </td><td> -298 </td><td> 2845 </td><td> 70 </td></tr><tr><td> MW-27 </td><td> -18 </td><td> ND * </td><td> ND * </td><td> ND * </td></tr><tr><td> MW-28 </td><td> -25 </td><td> -190 </td><td> 1695 </td><td> 81 </td></tr><tr><td> MW-30 </td><td> -35 </td><td> -254 </td><td> 2365 </td><td> 75 </td></tr><tr><td> MW-32 </td><td> -20 </td><td> ND * </td><td> ND * </td><td> ND * </td></tr><tr><td> MW-34 </td><td> -32 </td><td> -283 </td><td> 2670 </td><td> 72 </td></tr><tr><td> MW-35 </td><td> -25 </td><td> -598 </td><td> 7320 </td><td> 40 </td></tr><tr><td> MW-38 </td><td> -32 </td><td> -354 </td><td> 3515 </td><td> 65 </td></tr><tr><td> MW-41 </td><td> -28 </td><td> -232 </td><td> 2125 </td><td> 77 </td></tr><tr&gt; <td> MW-42 </td><td> -23 </td><td> -482 </td><td> 5280 </td><td> 52 </td></tr><tr><td colspan="5"> * ND没有数据 - 泵泄漏</td></tr></tbody></table> 表1. 二氧化碳 同位素测量和转换。CO 2同位素和放射性碳测量和转换在稿件中使用单位。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td colspan="2">参数</td><td>单位</td><td>值</td></tr><tr><td colspan="2">水文学</td><td></td><td></td></tr><tr><td rowspan="2"></td><td rowspan="2">导水率</td><td rowspan="2">毫升小时-1 </td><td> 0.44（含水） </td></tr><tr><td> 10（井） </td></tr><tr><td rowspan="2"></td><td rowspan="2">孔隙度（含水） </td><td rowspan ="2"&gt; </td><td> 0.48（含水） </td></tr><tr><td> 0.99（井） </td></tr><tr><td></td><td>堆积密度</td><td>摹厘米-3 </td><td> 1.4 </td></tr><tr><td></td><td>具体产量</td><td> 立方厘米厘米-3 </td><td> 0.2 </td></tr><tr><td></td><td>水力梯度</td><td>毫米-1 </td><td> 0.015 </td></tr><tr><td colspan="2"> CO 2的溶质运移</td><td></td><td></td></tr><tr><td></td><td>扩散系数</td><td>米2小时-1 </td><td> 5.77×10 -5 </td></tr><tr><td rowspan="2"></td><td>纵</td><td rowspan="2">米</td><td rowspan="2"> 6.1 </td></tr><tr><td>分散性</td></tr><tr><td rowspan="2"></td><td>水平横向</td><td rowspan="2">米</td><td rowspan="2"> 0.61 </td></tr><tr><td>分散性</td></tr><tr><td rowspan="2"> &lt;/ TD&gt; <td>垂直横向</td><td rowspan="2">米</td><td rowspan="2"> 0.061 </td></tr><tr><td>分散性</td></tr><tr><td></td><td>土壤气体CO 2 </td><td> ％ </td><td> 0.56 </td></tr></tbody></table> 表2. ZOI模型参数。在ZOI模型和模拟使用的参数。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td rowspan="2">收集率水平</td><td rowspan="2">收集率</td><td rowspan="2">背景浓度</td><td colspan="4"> ZOI尺寸</td></tr><tr><td>纵</td><td>横</td><td>深度</td><td>卷</td></tr><tr><td></td><td> （克/小时） </td><td> （克/米3） </td><td> （米） </td><td></td><td></td><td> （m 3）的</td></tr><tr><td>最大值</td><td> 0.0131 </td> &lt;TD&gt; 17.6 </td><td> 2.47 </td><td> 0.77 </td><td> 0.13 </td><td> 0.193 </td></tr><tr><td>平均</td><td> 0.0048 </td><td> 6.5 </td><td> 2.28 </td><td> 0.72 </td><td> 0.12 </td><td> 0.176 </td></tr><tr><td>最低限度</td><td> 0.0003 </td><td> 4 </td><td> 2.16 </td><td> 0.68 </td><td> 0.11 </td><td> 0.149 </td></tr></tbody></table> 表3. ZOI模型输出型号输出的ZOI。此表描述了ZOI的三维体积。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td>好</td><td> f 涤纶 （％） </td><td>污染物降解率 （毫克C D -1±10％） </td><td>每单位时间和体积污染物降解 （毫克C M -3ð-1±15％） </td></tr><tr><td> MW-01 </td><td> 0 </td><td> NA </td><td> NA </td></tr><tr><td> MW-21 </td><td> 60 </td><td> 5.6 </td><td> 32 </td></tr><tr><td> MW-25¥ </td><td> 1 </td><td> 0 </td><td> 0 </td></tr><tr><td> MW-26 </td><td> 18 </td><td> 0.18 </td><td> 1 </td></tr><tr><td> MW-28 </td><td>五</td><td> 0.017 </td><td> 0.098 </td></tr><tr><td> MW-30 </td><td> 12 </td><td> 0.34 </td><td> 1.9 </td></tr><tr><td> MW-34 </td><td> 16 </td><td> 0.1 </td><td> 0.58 </td></tr><tr><td> MW-35 </td><td> 53 </td><td> 3.6 </td><td> 20 </td></tr><tr><td> MW-38 </td><td> 24 </td><td> 1.4 </td><td> 8.1 </td></tr><tr><td> MW-41 </td><td> 10 </td><td> 0.44 </td><td> 2.5 </td></tr><tr><td> MW-42 </td><td> 39 </td><td> 1.7 </td><td> 9.8 </td></tr><tr><td colspan="4"> NA不适用- MW-01用作背景（ 例如，没有污染） </td></tr><tr><td colspan ="4"&gt;¥假定为纯粹平衡驱动（ 例如 ，无呼吸） </td></tr></tbody></table> 表4.缩放污染物降解的估计。估计为每单位时间和采样井单位体积污染物的降解。

Watch this Scientific Journal Video about Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses at JoVE.com

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

A protocol is described wherein CO2 mineralized from organic contaminant (derived from petroleum feedstocks) biodegradation is trapped, quantified, and analyzed for 14C content. A model is developed to determine CO2 capture zone's spatial extent. Spatial and temporal measurements allow integrating contaminant mineralization rates for predicting remediation extent and time.

测量碳为基础的污染物矿化结合使用CO<sub&gt; 2</sub&gt;助焊剂和放射性碳分析

A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate ...

measuring-carbon-based-contaminant-mineralization-using-combined-co2

Universidad San Sebastian

Research

JoVE Journal

Environment

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

11.6K 次观看.  US Naval Research Laboratory. A protocol is described wherein CO2 mineralized from organic contaminant (derived from petroleum feedstocks) biodegradation is trapped, quantified, and analyzed for 14C content. A model is developed to determine CO2 capture zone's spatial extent. Spatial and temporal measurements allow integrating contaminant mineralization rates for predicting remediation extent and time. 

视频: Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

Measuring Fluxes of Mineral Nutrients and Toxicants in Plants with Radioactive Tracers

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. Radioisotope tracing is a major technique used to measure such fluxes, both within plants, and between plants and their environments. Flux data obtained with radiotracer protocols can help elucidate the capacity, mechanism, regulation, and energetics of transport systems for specific mineral nutrients or toxicants, and can provide insight into compartmentation and turnover rates of subcellular mineral and metabolite pools. Here, we describe two major radioisotope protocols used in plant biology: direct influx (DI) and compartmental analysis by tracer efflux (CATE). We focus on flux measurement of potassium (K+) as a nutrient, and ammonia/ammonium (NH3/NH4+) as a toxicant, in intact seedlings of the model species barley (Hordeum vulgare L.). These protocols can be readily adapted to other experimental systems (e.g., different species, excised plant material, and other nutrients/toxicants). Advantages and limitations of these protocols are discussed.

In planta measurement of nutrient and toxicant fluxes is essential to the study of plant nutrition and toxicity. Here, we cover radiotracer protocols for influx and efflux determination in intact plant roots, using potassium (K+) and ammonia/ammonium (NH3/NH4+) fluxes as examples. Advantages and limitations of such techniques are discussed.

植物与放射性示踪剂测量矿质营养和毒物的通量

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. ...

科研

环境科学

Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies.

This article showcases the static chamber-based method for measurement of greenhouse gas flux from soil systems. With relatively modest infrastructure investments, measurements may be obtained from multiple treatments/locations and over timeframes ranging from hours to years.

从农业土壤使用静态钱伯斯温室气体流量测量

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the ...

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

Continuing increases in atmospheric carbon dioxide concentrations (CA) mandate techniques for examining impacts on terrestrial ecosystems. Most experiments examine only two or a few levels of CA concentration and a single soil type, but if CA can be varied as a gradient from subambient to superambient concentrations on multiple soils, we can discern whether past ecosystem responses may continue linearly in the future and whether responses may vary across the landscape. The Lysimeter Carbon Dioxide Gradient Facility applies a 250 to 500 &#181;l L-1 CA gradient to Blackland prairie plant communities established on lysimeters containing clay, silty clay, and sandy soils. The gradient is created as photosynthesis by vegetation enclosed in in temperature-controlled chambers progressively depletes carbon dioxide from air flowing directionally through the chambers. Maintaining proper air flow rate, adequate photosynthetic capacity, and temperature control are critical to overcome the main limitations of the system, which are declining photosynthetic rates and increased water stress during summer. The facility is an economical alternative to other techniques of CA enrichment, successfully discerns the shape of ecosystem responses to subambient to superambient CA enrichment, and can be adapted to test for interactions of carbon dioxide with other greenhouse gases such as methane or ozone.

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

The Lysimeter Carbon Dioxide Gradient Facility creates a 250 to 500 &#181;l L-1 linear carbon dioxide gradient in temperature-controlled chambers housing grassland plant communities on clay, silty clay, and sandy soil monoliths. The facility is used to determine how past and future carbon dioxide levels affect grassland carbon cycling.

一个外线<sub&gt; 2</sub&gt;浓度梯度用于测试CO<sub&gt; 2</sub&gt;浓度与土壤对草地生态系统功能的影响

Continuing increases in atmospheric carbon dioxide concentrations (CA) mandate techniques for examining impacts on terrestrial ecosystems. Most ...

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in nutrient and gas cycles. After cores with intact sediment-water interfaces are collected, they are submerged in incubation tanks and kept under aerobic conditions at in situ temperatures. To initiate a time course of overlying water chemistry, cores are sealed without bubbles using a top cap with a suspended stirrer. Time courses of 4-7 sample points are used to determine the rate of sediment water exchange. Artificial illumination simulates day-time conditions for shallow photosynthetic sediments, and in conjunction with dark incubations can provide net exchanges on a daily basis. The net measurement of N2 is made possible by sampling a time course of dissolved gas concentrations, with high precision mass spectrometric analysis of N2:Ar ratios providing a means to measure N2 concentrations. We have successfully applied this approach to lakes, reservoirs, estuaries, wetlands and storm water ponds, and with care, this approach provides valuable information on biogeochemical balances in aquatic ecosystems.

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

Here, we present small core incubations for the measurement of sediment-water gas and solute exchange. These will provide reliable measurements of sediment-water exchange that assess the role of sediment in influencing biological and biogeochemical processes in aquatic ecosystems.

Ø的底栖交易所<sub&gt; 2</sub&gt;，N<sub&gt; 2</sub&gt;和营养盐使用小的核心孵化

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in ...

Assessment of Labile Organic Carbon in Soil Using Sequential Fumigation Incubation Procedures

Management practices and environmental changes can alter soil nutrient and carbon cycling. Soil labile organic carbon, a readily decomposable C pool, is highly sensitive to disturbance. It is also the primary substrate for soil microorganisms, which is fundamental to nutrient cycling. Due to these attributes, labile organic carbon (LOC) has been identified as an indicator parameter for soil health. Quantifying the turnover rate of LOC also aids in understanding changes in soil nutrient cycling processes. A sequential fumigation incubation method has been developed to estimate soil LOC and potential C turnover rate. The method requires fumigating soil samples and quantifying CO2-C respired during a 10 day incubation period over a series of fumigation-incubation cycles. Labile organic C and potential C turnover rate are then extrapolated from accumulated CO2 with a negative exponential model. Procedures for conducting this method are described.

Labile organic carbon (LOC) and the potential carbon turnover rate are sensitive indicators of changes in soil nutrient cycling processes. Details are provided for a method based on fumigating and incubating soil in a series of cycles and using the CO2 accumulated during the incubation periods to estimate these parameters.

活性有机碳评估土壤中连续熏蒸孵化程序

Management practices and environmental changes can alter soil nutrient and carbon cycling. Soil labile organic carbon, a readily decomposable C pool, is ...

Reservoir Condition Pore-scale Imaging of Multiple Fluid Phases Using X-ray Microtomography

X-ray microtomography was used to image, at a resolution of 6.6 &#181;m, the pore-scale arrangement of residual carbon dioxide ganglia in the pore-space of a carbonate rock at pressures and temperatures representative of typical formations used for CO2 storage. Chemical equilibrium between the CO2, brine and rock phases was maintained using a high pressure high temperature reactor, replicating conditions far away from the injection site. Fluid flow was controlled using high pressure high temperature syringe pumps. To maintain representative in-situ conditions within the micro-CT scanner a carbon fiber high pressure micro-CT coreholder was used. Diffusive CO2 exchange across the confining sleeve from the pore-space of the rock to the confining fluid was prevented by surrounding the core with a triple wrap of aluminum foil. Reconstructed brine contrast was modeled using a polychromatic x-ray source, and brine composition was chosen to maximize the three phase contrast between the two fluids and the rock. Flexible flow lines were used to reduce forces on the sample during image acquisition, potentially causing unwanted sample motion, a major shortcoming in previous techniques. An internal thermocouple, placed directly adjacent to the rock core, coupled with an external flexible heating wrap and a PID controller was used to maintain a constant temperature within the flow cell. Substantial amounts of CO2 were trapped, with a residual saturation of 0.203 &#177; 0.013, and the sizes of larger volume ganglia obey power law distributions, consistent with percolation theory.

We present a methodology for the imaging of multiple fluid phases at reservoir conditions by the use of x-ray microtomography. We show some representative results of capillary trapping in a carbonate rock sample.

多重流体相储层孔隙条件级成像使用X射线微断层

X-ray microtomography was used to image, at a resolution of 6.6 &#181;m, the pore-scale arrangement of residual carbon dioxide ganglia in the pore-space ...

工程学

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonate (CaCO3) profiles. The objective is to describe a simple conceptual model and detailed protocol for repeatable field and laboratory measurements of these quantities. Here, accurate elevation is measured using a ground-based differential global positioning system (GPS); other data acquisition methods could be applied to the same basic method. Soil samples are collected from prescribed depth intervals and analyzed in the lab using an efficient and precise modified pressure-calcimeter method for quantitative analysis of inorganic carbon concentration. Standard statistical methods are applied to point data, and representative results show significant correlations between changes in soil surface layer CaCO3 and changes in elevation consistent with the conceptual model; CaCO3 generally decreased in depositional areas and increased in erosional areas. Maps are derived from point measurements of elevation and soil CaCO3 to aid analyses. A map of erosional and depositional patterns at the study site, a rain-fed winter wheat field cropped in alternating wheat-fallow strips, shows the interacting effects of water and wind erosion affected by management and topography. Alternative sampling methods and depth intervals are discussed and recommended for future work relating soil erosion and deposition to soil CaCO3.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonates. Repeatable methods for field and laboratory measurements of these quantities and data analysis methods are described here.

农业经营条件下土壤侵蚀和沉积与土壤碳酸盐浓度关系的测量与制图

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes ...

Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters. Millimeter scale subsampling allows for sub-annual to monthly analysis of the sedimentary record, an order of magnitude higher than typical sampling schemes. The extruder consists of a 2 m aluminum frame and base, two core tube clamps, a threaded-rod, and a 1 m piston. The sediment core is placed above the piston and clamped to the frame. An acrylic sampling collar is affixed to the upper 5 cm of the core tube and provides a platform from which to extract sub-samples. The piston is rotated around the threaded-rod at calibrated intervals and gently pushes the sediment out the top of the core tube. The sediment is then isolated into the sampling collar and placed into an appropriate sampling vessel (e.g., jar or bag). This method also preserves the unconsolidated samples (i.e., high pore water content) at the surface, providing a consistent sampling volume. This mm scale extrusion method was applied to cores collected in the northern Gulf of Mexico following the Deepwater Horizon submarine oil release. Evidence suggests that it is necessary to sample at the mm scale to fully characterize events that occur on the monthly time-scale for continental slope sediments.

An extrusion method using a calibrated threaded-rod is presented, which allows for mm scale subsampling of aquatic sediment cores. Millimeter-scale sampling is necessary to fully characterize recent event stratigraphy in sediment records.

沉积物核心挤压法在毫米的分辨率用校准，螺纹杆

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, ...

化学

Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been applied in paleodietary, paleoecological, and paleoenvironmental research from recent historical periods back to over 10 million years ago. Bulk approaches provide a representative sample for the period of enamel mineralization, while sequential samples within a tooth can track dietary and environmental changes during this period. While these methodologies have been widely applied and described in archaeology, ecology, and paleontology, there have been no explicit guidelines to aid in the selection of necessary lab equipment and to thoroughly describe detailed laboratory sampling and protocols. In this article, we document textually and visually, the entire process from sampling through pretreatment and diagenetic screening to make the methodology more widely available to researchers considering its application in a variety of laboratory settings.

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been used as a proxy for individual diet and environmental reconstruction. Here, we provide a detailed description and visual documentation of bulk and sequential tooth enamel sampling as well as pretreatment of archaeological and paleontological samples.

用于稳定碳氧同位素分析的牙釉质碳酸盐的取样与预处理

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been applied in paleodietary, paleoecological, and ...

生物化学

Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites

This protocol is an example of utilizing the eddy covariance (EC) technique to investigate spatially and temporally averaged net CO2 fluxes (net ecosystem production, NEP), in non-typical ecosystems, on a currently reforested windthrow area in Poland. After a tornado event, a relatively narrow &#8220;corridor&#8221; was created within surviving forest stands, which complicates such kind of experiments. The application of other measuring techniques, such as the chamber method, is even more difficult under these circumstances, because especially at the beginning, fallen trees and in general great heterogeneity of the site provide a challenging platform to perform flux measurements and then to properly upscale obtained results. In comparison with standard EC measurements carried out in untouched forests, the case of windthrow areas requires special consideration when it comes to the site location and data analysis in order to ensure their representativeness. Therefore, here we present a protocol of real-time, continuous CO2 flux measurements at a dynamically changing, non-ideal EC site, which includes (1) site location and instrumentation setup, (2) flux computation, (3) rigorous data filtering and quality control, and (4) gap filling and net fluxes partitioning into CO2 respiration and absorption. The main advantage of the described methodology is that it provides a detailed description of the experimental setup and measurement performance from scratch, which can be applied to other spatially limited ecosystems. It can also be viewed as a list of recommendations on how to deal with unconventional site operation, providing a description for non-specialists. Obtained quality-checked, gap filled, half-hour values of net CO2, as well as absorption and respiration fluxes, can be finally aggregated into daily, monthly, seasonal or annual totals.

Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites

The presented protocol uses the eddy covariance method at non-typical locations, applicable to all types of short-canopy ecosystems with limited area, on a currently reforested windthrow site in Poland. Details of measuring site setup rules, flux calculations and quality control, and final result analysis, are described.

非理想涡流位点的 CO2通量测量

This protocol is an example of utilizing the eddy covariance (EC) technique to investigate spatially and temporally averaged net CO2 fluxes (net ecosystem ...

测量碳为基础的污染物矿化结合使用CO

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