Fate and Transport of Biocolloids in Beach Sand

[933230]与无数点源和非点源粪便污染相关的细菌水平升高是导致海滩关闭和健康咨询的主要因素。被人类和动物粪便污染的洗浴水和沙滩对游泳者和海滩游客构成严重的健康风险。虽然地方公共当局定期监测洗浴水中粪便指标的水平，以评估对游泳者的健康威胁，但直接接触沙子的人接触病原体的风险在很大程度上被忽视了。目前，尽管研究表明，指示生物和病原体可以大量出现并持续存在于淡水海岸线附近收集的地下沉积物中，但仍没有水质标准用于检测海滩砂及其孔隙水。因此，拟议研究的总体目标是提高对控制生物胶体（如病毒、细菌和原生动物）在沙滩冲滩区的命运和运输的机制的基本理解。具体目标包括：(1)建立数学模型，描述与冲刷带相关的流动条件下多孔介质中生物胶体的运输和保留特征。(2)在控制良好的实验室规模柱和实验室模型沙滩中研究胶体颗粒的运移机制和存活特性；测定不同流动条件下的沉积速率。(3)将模型研究和实验室实验的结果推广到实际情况，并通过实地调查验证输运模型。对指示生物和病原体进入沙子的基本机制以及有助于其随后存活的因素的了解，为监测和减轻海滩污染开辟了新的范例。数学建模、实验室规模实验和实地调查的系统结合是本研究的创新之处。在过去的几年里，PI一直在研究多孔介质中细菌的命运和运输，为大密尔沃基流域开发雨水管理模型，并研究生物膜的微生物生态学。Co-PI一直在开发一种多功能水下微型PIV系统（UWMPIV）系统，用于研究河流、湖泊和海洋中水-沉积物和水-空气界面附近的小尺度湍流结构。这个项目是建立在PI？他们在环境微生物学和流体动力学方面的专业知识在他们最近的出版物和项目中有记载。预计本研究的结果将促进这两个领域的现有知识。该项目的智力价值将为教学、培训和学习提供坚实的基础。一门新的基于探究的实验课程将汇集来自不同背景的本科生和研究生，包括生物学、化学和地球科学。本项目的研究成果将添加为？热门话题?新课程的模块。以前和现在的研究生将有机会担任校园内招收的本科生的导师。通过向理工科学生介绍环境工程问题，可以吸引更多的女性和少数民族本科生参加工程研究生课程。研究结果将通过参加地方、国家和国际会议和在同行评议的期刊上发表的方式，传播给决策者、水质管理人员、公共卫生和环境团体、研究人员和公众。将举办一个国际研讨会，为美国和亚洲的研究人员提供一个论坛，讨论海滩水监测和管理方面的挑战。ppi还将与威斯康星大学的EWB学生分会合作，为危地马拉和肯尼亚的村民提供安全的饮用水和娱乐用水。

0933230LiElevated level of bacteria associated with fecal contamination from a myriad of point and non-point sources is the major factor leading to beach closings and health advisories. Bathing water and beach sand contaminated with human and animal wastes pose a serious health risk to swimmers and beachgoers. While local public authorities routinely monitor the level of fecal indicators in bathing water to assess the health threat for swimmers, the risk of pathogen exposure for those who come into direct contact with sand has been largely neglected. Currently, no water quality criterion exists for testing beach sand and its pore water, even though studies have revealed that indicator organisms and pathogens can occur in high numbers and persist in subsurface sediment collected near freshwater shorelines.Thus, the overall goal of the proposed research is to improve the basic understanding of mechanisms governing the fate and transport of biocolloids, e.g., viruses, bacteria and protozoa, in the swash zone on sandy beaches. The specific objectives include: (1) Develop mathematical models that characterize biocolloids transport and retention in porous media under flow conditions relevant to the swash zone.(2)Study the transport mechanisms and survival characteristics of colloidal particles in well-controlled laboratory scale columns and a laboratory model sandy beach; determine the deposition rate under various flow conditions. (3)Extend the results from modeling studies and laboratory experiments to real-world situations and verify the transport model through field investigations.Understanding of the fundamental mechanisms governing the transport of indicator organisms and pathogens into sand and factors contribute to their subsequent survival opens a new paradigm in beach pollution monitoring and mitigation. The systematic integration of mathematical modeling, laboratory scale experiments and field investigation is an innovative aspect of this research. For the past a few years the PI has been investigating the fate and transport of bacteria in porous media, developing models for stormwater management for the Greater Milwaukee Watershed and studying microbial ecology of biofilms. The Co-PI has been developing a versatile in-situ Underwater Miniature PIV System (UWMPIV) system to investigate small-scale turbulence structures near water-sediment and water-air interfaces in Rivers, Lakes and Oceans. This project is built upon both PI?s expertise in environmental microbiology and hydrodynamics as documented in their recent publications and projects. It is expected that results from this research will advance the current knowledge in both fields.The intellectual merit of this project will provide a firm foundation for teaching, training and learning. A new inquiry based laboratory course that brings together undergraduate and graduate students from a diverse background including, biology, chemistry and geoscience, will be developed. The research results from this project will be added as ?hot topics? modules to the new course. Previous and current graduate students will have the opportunity to serve as mentors for undergraduate students recruited across the campus. By introducing environmental engineering issues to students majoring in science, it is possible to attract more women and minority undergraduate students to the engineering graduate program. The research results will be disseminated to policy makers, water quality managers, public health and environmental groups, researchers, and the public, through participation in local, national and international conferences and publication in peer-reviewed journals. An international workshop will be organized to provide a forum for researchers in the US and Asia to discuss the challenges in beach water monitoring and management. The PIs will also work with the EWB student chapter at UWM to provide safe drinking water and recreational water to villagers in Guatemala and Kenya.