Animal Waste, Water Quality and Human Health

5Transport of microbial pollution incatchment systemsChristobel Ferguson and David Kay5.1 POTENTIAL OF MICROBIAL MODELS TO DESCRIBECATCHMENT COMPLEXITYHumans, wildlife and domestic livestock are all potential sources of fecal indicatororganisms (FIOs) and/or pathogens in surface waters. To assess the microbial risksto surface water quality in drinking-water catchments it is necessary to quantify boththe contributions from each of these sources and the processes that govern their fateand transport to water bodies and waterways. Catchment characteristics vary widelyover space and time. Such a quantification and attribution therefore requires anunderstanding of the natural, riparian, farm and urban processes that can occur indrinking-water catchments. An initial approach is to develop a conceptual modelthat assists in the identification of the relevant natural and anthropogenicprocesses, as presented in Figure 5.1. These include environmental inactivation,soil retention, host prevalence, buffer strip entrapment, manure treatment, wetland© 2012 World Health Organization (WHO). Animal Waste, Water Quality and Human Health. Editedby Al Dufour, Jamie Bartram, Robert Bos and Victor Gannon. ISBN: 9781780401232. Published byIWA Publishing, London, UK.