Reducing Properties of Anaerobic Sediments: Molecular Probe Studies of Biogeochemistry and Contaminant Fate

该奖项授予俄勒冈州研究生院环境科学与工程系的Paul G.Tratnyek博士、V.Renganathan博士和David R.Boone博士，表彰他们对厌氧沉积物中污染物去向的研究。这项研究得到了化学和地球科学部以及MPS多学科活动办公室的支持。一些污染物在厌氧土壤中发生还原，但控制化学反应的生化和地球化学因素尚不清楚。这项研究的目标是开发分子探针，以阐明海岸、河口和淡水环境中沉积物的还原过程。初步工作将使用2-氯苯乙酮(2-CAP)来监测还原过程。当这种化学物质通过电子转移反应时被还原为2-氯甲基苯甲醇，当它通过氢化物转移还原时被还原为苯乙酮。通过测量沉积物中存在的这三种化合物的数量，就可以确定还原的速度和土壤的还原能力。苯乙酮的形成意味着与胞外烟酰胺的反应，烟酰胺是此类体系中为数不多的可能的氢化物来源之一。结果将与微生物学研究相关联，以开发不同土壤中生物地球化学还原过程的模型。将研究更多的分子探针，以更充分地表征真实环境材料的还原能力。污染物，如氯代烃、亚硫醚和苯二酚，可以通过化学反应在来自有机和无机环境来源的污染物中添加电子而在土壤中转化。关于这些反应如何发生的细节，以及它们在各种类型的土壤中发生的速度和程度，还不足以预测环境中的污染物命运。在这项研究中，将开发一种检验各种模型的环境相关性的通用方法，其长期目标是为监管决策提供有用的预测工具。

This award in the Environmental Geochemistry and Biogeochemistry Program is made to Drs. Paul G. Tratnyek, V. Renganathan, and David R. Boone of the Department of Environmental Science and Engineering, Oregon Graduate Institute, for studies of contaminant fate in anaerobic sediments. The research is supported by the Divisions of Chemistry and Earth Sciences and the MPS Office of Multidisciplinary Activities. Some contaminants undergo reduction in anaerobic soils, but the biochemical and geochemical factors controlling the chemical reaction are not well understood. The goal of this research is to develop molecular probes that can elucidate reduction processes in sediments from coastal, estuarine, and freshwater environments. Initial work will use 2-chloroacetophenone (2-CAP) to monitor the reduction process. This chemical is reduced to 2-(chloromethyl)benzyl alcohol when it reacts by electron transfer, and to acetophenone when reduced by hydride transfer. By measuring the amount of each of these three compounds present in the sediment, the rate of reduction and the capacity of the soil for reduction will be determined. The formation of acetophenone implies reaction with extracellular nicotinamide, one of the few possible sources of hydride in such systems. Results will be correlated with microbiological studies to develop a model of the biogeochemical reduction process in various soils. Additional molecular probes will be studied as means of more fully characterizing the reducing capacity of real environmental materials. Pollutants such as chlorohydrocarbons, sulfoxides, and quinones can be transformed in soils by chemical reactions in which electrons are added to the contaminant from environmental sources, both organic and inorganic. The details about how these reactions occur as well as the rates and extent to which they occur in various types of soils are not sufficiently understood to predict contaminant fate in the environment. In this research a general method to test the environmental relevance of various models will be developed with the long-term goal of providing a predictive tool useful to regulatory decision-making.