Fate and Transport of Biocolloids in Beach Sand

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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.