Escherichia coli removal in tropical Oligotrophic and Eutrophic lakes

Abstract

The mechanisms by which oligotrophic and eutrophic lakes rid itself of Escherichia coli or faecal coliforms are still not clearly understood. This study sought to review the various means by which E. coli or faecal coliforms are inactivated or removed in lakes. The review cited temperature, solar radiation, predation, starvation, attachment and sedimentation as key factors that aid the removal of E. coli in lakes. In eutrophic lakes additional factors such as the role of algal biomass may play a role due to increased pH and dissolved oxygen levels attributed to algal presence. Algal toxins or exudates may also play a role although this is still under debate. The interactive effect of two or more of these factors on E. coli inactivation and the relative importance of these mechanisms on E. coli removal are still not known. Areas for further research include the role of algae in sedimenting E. coli or faecal coliforms and the possible role of algal exudates on E. coli inactivation