POLLUTANT BIOAVAILABILITY LEADING TO STRUCTURED MODELS FOR CONTAMINANT FATE

该项目旨在评估用于研究的微尺度方法， 土壤和沉积物中污染物的生物有效性。总体目标是 更好地理解微生物的机理， 微环境有利因素控制着分布、生物降解 以及污染物的迁移，如单环和多环芳烃 碳氢化合物（PAHs）（如甲苯、萘和菲），以及 多孔介质中的重金属（如Cd和Pb）。方法是开发 并应用显微镜检测和鉴定方法， 荧光抗体（Fab）染色，显微放射自显影（MARG），和 寡核苷酸荧光原位杂交（FISH），以确定 微尺度分布和不同的活动模式， 细菌（和基因）和污染化学品相对于非生物 土壤和沉积物的成分。传统光电 显微镜方法也将用于差异染色， 识别非生命成分。应用该等 微尺度方法将使人们更好地了解污染物 相对于非生物组成部分的分布和可得性， 能够参与其生物降解的细菌细胞，或 运输 在后续项目中，新开发的Fab-MARG程序将 在甲苯的宏观和微观研究中得到完善 恶臭假单胞菌F1在有机沉积物中的生物降解作用， 随后将其应用于多环芳烃的类似研究中。新鱼标 将开发方法来鉴定不可培养的细菌， 荧光标记的核糖体RNA靶向寡核苷酸 Fab-MARG程序的杂交变化。Fab检测方法 将进行测试，以确定污染化学品和腐殖成分 在土壤或沉积物基质中。其他差分光和电子 显微镜方法，包括STEM-MARG和STEM-EDX，自体荧光 和荧光染色的土壤基质成分，和胶体金- 标记的抗体染色，也将测试它们在 估计污染物分布与微结构的关系， 土壤和沉积物颗粒。 在此基础上，建立了一个宏尺度模型结构 嵌入其中的组件允许直接应用微尺度 从数据到宏观性能。生物降解动力学与污染物 在该结构化模型中使用的分布参数将是 使用微尺度方法进行评估， 确认物理和化学之间的相互关系 污染物的有效性及其在土壤中的矿化速率 和沉积物。在提出的机制的理解 研究将为继续开发更强大的 污染物生物利用度、降解和迁移的模型， 以前也有过。这些模型的开发预计将有助于 风险评估和风险管理活动，并降低成本 通过更准确地预测污染物， 比目前的模型更好。

This project aims to evaluate microscale methods for use in studies of pollutant bioavailability in soil and sediment. The overall goal is to provide a better mechanistic understanding of microbiological and microenvironmental favors controlling the distribution, biodegradation and transport of pollutants such as mono- and polycyclic aromatic hydrocarbons (PAHs) (e.g. toluene, naphthalene and phenanthrene) and heavy metals (e.g. Cd and Pb) in porous media. The approach is to develop and apply microscopic detection and identification methods such as fluorescent antibody (Fab) staining, microautoradiography (MARG), and oligonucleotide fluorescent in situ hybridization (FISH) to determine the microscale distribution and differential activity patterns of specific bacteria (and genes) and pollutant chemicals relative to non-living components of soil and sediment. Conventional light and electron microscopic methods will also be used for differential staining and identification of the non-living components. Application of these microscale methods will result in a better understanding of pollutant distribution and availability relative to the non-living components and the bacterial cells capable that participate in their biodegradation or transport. In the continuation project, a newly developed Fab-MARG procedure will be refined in combined macro- and microscale studies of toluene biodegradation by Pseudomonas putida Fl in organic sediment and subsequently be applied in similar studies with PAHs. New FISH-MARG methods will be developed for identifying non-culturable bacteria using a fluorescently labeled ribosomal RNA-targeted oligonucleotide hybridization variation of the Fab-MARG procedure. Fab detection methods will be tested for identifying pollutant chemicals and humic components in soil or sediment matrix. Other differential light and electron microscopic methods, including STEM-MARG and STEM-EDX, autofluorescence and fluorochrome staining of soil matrix components, and colloidal gold- labeled antibody staining, will also be tested for their efficacy in estimating pollutant distribution in relation to the microstructure of soil and sediment particles. A macroscale model structure was developed with microscale model components embedded in it that allow for direct application of microscale data to macroscale performance. Biodegradation kinetic and pollutant distribution parameters for use in this structured model will be evaluated using the microscale methodologies as they become available to confirm the interrelationships between the physical and chemical availability of the contaminants and their mineralization rates in soils and sediments. The mechanistic understanding obtained in the proposed research will provide the basis for continued development of more robust models for pollutant bioavailability, degradation, and transport than have been available before. Development of such models is expected to aid exposure assessment and risk management activities and reduce the costs of bioremediation by allowing for more accurate predictions of pollutant behavior than is possible with current models.