ABSTRACT
Epidemiological data are frequently used to provide a basis for public health decisions and as an aid to the regulatory process. This is certainly true when developing safeguards for recreational waters where hazardous substances or pathogens discharged to coastal and inland waters may pose a serious risk of illness to individuals who use the waters. Epidemiological studies of human populations not only provide evidence that swimming-associated illness is related to environmental exposure, but also can establish an exposure-response gradient which is essential for developing risk-based regulations. Epidemiology has played a significant role in providing information that characterises risks associated with exposure to faeces contaminated recreational waters. The use of epidemiological studies to define risk associated with swimming in contaminated waters has been criticised because the approach used to collect the data is not experimental in nature. This perception is unlikely to change, given the highly variable environments where recreational exposures take place. Although the variables may be difficult to control, it is possible to carry out credible studies by following certain standard practices that are given below. This Chapter discusses the place of epidemiological investigations in providing information to support recreational water management and the scientific basis of “health-based” regulation.
