Microbiological impact of diffuse pollution sources on water quality

This chapter outlines some of the impacts that diffuse pollution inputs can have on water quality and introduces some of the waterborne microbial contaminants and emerging pollutants of human and/or environmental health significance. The chapter also highlights some of the challenges associated with successfully identifying and mitigating diffuse sources of contamination and mentions some of the limitations of traditional faecal indicators (e.g., E. coli, intestinal enterococci). The emergence of new and potentially promising indicators is subsequently mentioned including culture-dependent bacteriophage-based approaches (e.g., somatic coliphage, Bacteroides phage) and culture-independent molecular-based methods (e.g., Pepper Mild Mottle Virus and crAssphage). There is considerable focus throughout the chapter on agricultural inputs of diffuse pollution, as they are often a key driver of poor microbiological water quality in many catchments around the world. Specific case studies from different geographical settings are also featured in the chapter and provide the reader with information on the different ways in which diffuse pollution monitoring and modelling is being used to support more effective catchment management.