Field-scale study to evaluate the role of bacterial chemotaxis in natural attenuation of groundwater contaminants

评估细菌趋化性在地下水污染物自然衰减中的作用的现场研究

• 批准号: 0408454
• 负责人: Roseanne Ford
• 金额: --
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0408454&HistoricalAwards=false
• 关键词: Field; scale; study; evaluate; role

0408454FordThe remediation of polluted groundwater is often limited because chemical contaminants trapped within interstices of the soil matrix are not accessible to groundwater flow paths. One mechanism by which pollutant-degrading bacteria may penetrate these less conductive regions is chemotaxis, the ability of bacteria to sense chemical concentration gradients and swim toward higher concentrations of contaminants. Chemotactic bacteria able to migrate from highly conductive regions of the aquifer toward the contaminant source would increase the microbial population in the vicinity of the contaminant and thereby enhance the overall rate of degradation and removal. Objective and Approach: The objective of this project is to determine the degree to which chemotactic bacteria may enhance the degradation of chemical pollutants near a source zone in natural groundwater systems. A series of field-scale investigations will be conducted at the USGS Cape Cod Toxic-Substances Hydrology Research Site. To aid in the design of the field-scale study, preliminary studies will be conducted in well-controlled two-dimensional sand box systems. The sand box design provides the added benefit of being able to visualize the flow patterns and analyze the spatial distributions of contaminant and bacteria along the flow path without all the complexities of a large field study.Intellectual Merit: Although number of laboratory-scale experiments have implicated bacterial chemotaxis as an important mechanism for transport of bacteria through saturated porous media, its ramifications at the field-scale have not been evaluated. A culminating experiment at the field-scale will address the question of whether chemotactic responses observed over length scales of centimeters in the lab give rise to larger scale effects that are observable in the field.Broad Impact: A new partnership between researchers at the University of Virginia and the US Geological Survey brings together expertise in bacterial chemotaxis and extensive field experience involving motile microorganisms. Investigators with a proven commitment to recruiting underrepresented groups in engineering will broadly educate one graduate and two undergraduate students through the University of Virginia's Program for Interdisciplinary Research in Contaminant Hydrology. Outreach to two local high schools will introduce students and their teachers to molecular biology techniques and the use of engineered organisms in laboratory and field-scale investigations. Results from this study will be used to assess the feasibility of monitored natural attenuation as a treatment option at contaminated sites where biological degradation has been documented

0408454福特 污染地下水的修复通常受到限制，因为截留在土壤基质间隙内的化学污染物无法进入地下水流道。 污染物降解细菌渗透这些导电性较差的区域的一种机制是趋化性，即细菌感知化学浓度梯度并游向更高浓度污染物的能力。趋化细菌能够从含水层的高导电区域向污染物源迁移，会增加污染物附近的微生物种群，从而提高总体降解和去除率。目标和方法：该项目的目标是确定趋化细菌增强天然地下水系统源区附近化学污染物降解的程度。美国地质调查局科德角有毒物质水文学研究站将进行一系列实地调查。为了帮助现场规模研究的设计，初步研究将在控制良好的二维沙箱系统中进行。沙箱设计提供了额外的好处，即能够可视化流动模式并分析沿流动路径的污染物和细菌的空间分布，而无需进行大型现场研究的所有复杂性。 智力优点：尽管大量实验室规模的实验表明细菌趋化性是细菌通过饱和多孔介质运输的重要机制，但其在现场规模的影响尚未得到评估。现场规模的最终实验将解决实验室在厘米尺度上观察到的趋化反应是否会引起现场可观察到的更大规模效应的问题。广泛影响：弗吉尼亚大学和美国地质调查局研究人员之间的新合作伙伴关系汇集了细菌趋化性方面的专业知识和涉及运动微生物的广泛现场经验。 致力于招募工程领域代表性不足群体的研究人员将通过弗吉尼亚大学污染物水文学跨学科研究计划对一名研究生和两名本科生进行广泛教育。 向当地两所高中进行推广活动，将向学生及其教师介绍分子生物学技术以及工程生物体在实验室和现场规模研究中的使用。这项研究的结果将用于评估监测自然衰减作为已记录生物降解的污染场地的处理选择的可行性