Development of dynamic catchment scale microbial transport models

近年来，加拿大发生了大规模的饮用水污染事件，最引人注目的是安大略省沃尔克顿市市政系统的微生物污染，这表明有必要对环境中微生物污染物的命运和运输有更好的了解。制定预防水系统中引起疾病的微生物传播的战略需要有关病原体来源、生存和流动性的具体知识。目前存在一些知识空白，妨碍了动态流域尺度微生物运输模型的制定。影响环境中微生物与沉积物颗粒联系程度的机制和因素是一个需要进一步研究的领域。本研究的长期目标是开发一种基于物理的建模系统，该系统可用于预测由弥漫性污染源主导的流域内微生物的迁移。拟议研究的短期目标将集中在更好地理解和代表沉积物-微生物相互作用，包括：(i)量化和比较不同物理化学环境中细菌、病毒和原生动物指示生物对沉积物颗粒的吸附，（ii）描述微生物从陆地表面向接收水体输送的机制，（iii）确定农村流域内输送的悬浮沉积物的大小分布，并描述微生物如何在这些沉积物中分配，（iv）发展和检验方程式，以预测微生物在陆地表面和地表水内的运输。拟议的研究将产生信息和工具，有助于确定防止肠道微生物向地表水迁移的土地利用战略和结构控制。

Large scale drinking water contamination events that have occurred in Canada in recent years, most notably the microbial contamination of a municipal system in Walkerton, ON, have demonstrated the need to develop an improved understanding of the fate and transport of microbial contaminants in the environment. The development of strategies for preventing the transmission of disease causing microorganisms in water systems requires specific knowledge with respect to pathogen sources, survival, and mobility.  There are several knowledge gaps currently preventing the formulation of dynamic catchment scale microbial transport models.  The mechanisms and factors which influence the extent to which microorganisms associate with sediment particles within the environment is one area which requires further research.  The long-term goal of this research is to develop a physically based modeling system which can be used to predict microorganism transport within catchments dominated by diffuse pollution sources.  The short-term objectives of the proposed research will focus on better understanding and representing sediment-microorganism interactions, and include: (i) quantify and compare the adsorption of bacterial, viral and protozoan indicator organisms to sediment particles within varying physiochemical environments, (ii) characterize the mechanisms by which microorganisms are transported from land surfaces to receiving water bodies, (iii) determine the size distribution of suspended sediments transported within rural catchments and characterize how microorganisms partition within these sediments, and (iv) develop and test equations to predict the transport of microorganisms on land surfaces and within surface waters. The proposed research will generate information and tools which will aid in identifying land-use strategies and structural controls which will prevent the migration of enteric microorganisms to surface waters.