Chapter 8 * : SANITARY INSPECTION AND MICROBIOLOGICAL WATER QUALITY

Sanitary inspection, water quality determination and data analysis and interpretation are essential elements in characterising the microbiological safety of water in recreational areas. Sanitary inspection is a necessary adjunct to water microbiological analysis. A well-conducted sanitary inspection can identify sources of microbiological hazards, microbiological water quality data confirm the presence of hazards, and the two together allow an estimation of the risk of illness to bathers and other users. In assessing the microbiological quality of recreational waters, it will normally be necessary to conduct: • An intensive sanitary inspection (only once as part of an assessment or annually in monitoring programmes). • Periodic appraisal visits in which water quality analysis and shortened inspections are undertaken. • Follow-up appraisals to investigate abnormal events, new sources of pollution and extreme values of pollution indicators. One of the most important aspects of aquatic microbiology is related to several human diseases transmitted via water. The design and development of epidemiological surveillance studies described in Chapter 13 have led to the awareness of the magnitude of human morbidity and mortality associated with waterborne infectious diseases. The most relevant microorganisms and the associated waterborne infectious diseases are summarised in the WHO Guidelines for Safe Recreational Water Environments (WHO, 1998). The derivation of guideline values for microbiological quality are also discussed in the WHO Guidelines for Safe Recreational Water Environments (WHO, 1998). This present chapter deals with sanitary inspection, microbiological analytical methods and data handling and reporting. Strategies to implement sanitary inspections and recommendations for selection of the site and frequency of water sampling are given in Chapter 9. Specific methods for sampling and analysis are detailed in the following sections together with the different statistical procedures to express the overall microbiological water quality at a specific recreational water use area. It should be noted that a single beach or recreational area may vary widely in relation to microbiological measures of health risk within relatively short periods of time and thus the commonly used methods of defining a recreational water as passing or failing a defined microbiological standard has inherent limitations; these are discussed in this chapter and also in Chapter 9. A sanitary inspection is a search for, and evaluation of, existing and potential microbiological hazards that could affect the safe use of a particular stretch of recreational water or bathing beach. It provides the foundation required to design and implement an effective water quality sampling …