An experimental health-related classification for marine waters

Detailed epidemiological studies in the UK have shown a dose–response relationship between water quality and gastroenteritis experienced by bathers. Other predictors of gastroenteritis found in the studies provide comparative levels of risk attributable to, for example, certain types of food. The statistical distribution of faecal streptococci, based on log10 mean and log10 SD, is used to describe the exposure of the bathing population. The exposure distribution is used in combination with the dose–response relationship and other independent risk factors as a framework for a health-related “standards” system. The standard system defines a series of water quality thresholds which take into account variation in water quality. These categories could provide a basis for both “health-related” water quality objectives and advice to the public on potential health risks from bathing.