 The relative risk (RR) of illness for swimmers in polluted freshwater versus swimmers in unpolluted water was between 1-2 for the majority of the data sets reviewed.The same study concluded that bacterial indicators were not well correlated to virus concentrations.Survival of pathogens in waste materials, soil, or water, depends on many environmental factors including temperature, pH, organic matter content, moisture, exposure to light, and the presence of other organisms.