ABSTRACT
The history and application of microbiological standards to measure the quality of seawater for primary-contact recreational use and for the harvesting of shellfish are reviewed. Recent research concludes that enterococci, as indicator organisms, provide the most accurate correlation with gastrointestinal disorders attributed to swimming in contaminated waters. Accordingly, a linear relations has been established between mean enterococcus density per 100 ml and swimming associated gastrointestinal disorders per 1000 population, and in 1984 the U.S. Environmental Protection Agency (EPA) adopted these bacteria as the primary indicator organisms for recreational waters in lieu of the indicators applied up til then, mainly total and fecal coliforms. International, national, and local microbiological standards and guidelines are presented to provide the sanitary engineer with a water quality range for the marine environment. Before adaptation of particular set of standards, local and national circumstances as well as socioeconomic factors should be carefully reviewed. Moreover, the application of quantitative relationships between health risks and the level of indicator organisms should take into account the general health and immunity conditions of the local population