Development of dynamic catchment scale microbial transport models

近年来在加拿大发生的大规模饮用水污染事件，尤其是安大略省沃克顿一个市政系统的微生物污染，表明有必要更好地了解微生物污染物在环境中的去向和传输。制定防止致病微生物在水系统中传播的战略需要关于病原体来源、生存、和流动性。目前，有几个知识空白阻碍了动态流域尺度微生物传输模型的建立。影响微生物与环境中沉积物颗粒结合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个基于物理的模拟系统，可以用于预测以弥漫污染源为主的流域内的微生物传输。拟议研究的短期目标将集中在更好地理解和表示沉积物-微生物相互作用，包括：(I)量化和比较细菌的吸附，(2)确定微生物从陆地表面向接受水体输送的机制；(3)确定农村集水区内悬浮沉积物的粒度分布，并表征微生物如何在这些沉积物中分配；(4)建立和检验预测微生物在陆地表面和地表水中迁移的方程。拟议的研究将产生有助于确定土地利用战略和结构控制的信息和工具，以防止肠道微生物向地表水迁移。

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.