Modeling the Transport and Inactivation of E. coli and Enterococci in the Near-Shore Region of Lake Michigan

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• 作者：Lubo Liu ; Mantha S. Phanikumar ; Stephanie L. Molloy ; Richard L. Whitman ; Dawn A. Shively ; Meredith B. Nevers ; David J. Schwab ; Joan B. Rose
• 刊名：Environmental Science & Technology
• 出版年：2006
• 出版时间：August 15, 2006
• 年：2006
• 卷：40
• 期：16
• 页码：5022 - 5028
• 全文大小：515K
• 年卷期：v.40,no.16(August 15, 2006)
• ISSN：1520-5851

文摘

To investigate the transport and fate of fecal pollution atGreat Lakes beaches and the health risks associated withswimming, the near-shore waters of Lake Michigan andtwo tributaries discharging into it were examined for bacterialindicators of human fecal pollution. The enterococcushuman fecal pollution marker, which targets a putativevirulence factor-the enterococcal surface protein (esp)in Enterococcus faecium, was detected in 2/28 samples (7%)in the tributaries draining into Lake Michigan and in 6/30samples (20%) in Lake Michigan beaches. This was indicativeof human fecal pollution being transported in the tributariesand occurrence at Lake Michigan beaches. To understandthe relative importance of different processes influencingpollution transport and inactivation, a finite-elementmodel of surf-zone hydrodynamics (coupled with modelsfor temperature, E. coli and enterococci) was used.Enterococci appear to survive longer than E. coli, whichwas described using an overall first-order inactivationcoefficient in the range 0.5-2.0 per day. Our analysis suggeststhat the majority of fecal indicator bacteria variation canbe explained based on loadings from the tributaries. Sunlightis a major contributor to inactivation in the surf-zoneand the formulation based on sunlight, temperature andsedimentation is preferred over the first-order inactivationformulation.