Abstract
A brief outline is given of marine microbiology, relating to both natural microorganisms and those resulting from pollution. Microbial indicators of pollution and their methods of detection are discussed and recent epidemiological surveys of health effects associated with seawater recreational activities are reviewed. Reference is made to microbiological standards for bathing waters. It is evident that more work is required to elucidate the complex ecological interactions of marine microorganisms; that current microbial pollution indicators are in need of refinement; and that although recreational exposure to coastal waters has some association with the acquisition of minor illness, attempts to relate this to the microbiological quality of the water are confounding.