Microbiological and sanitary quality of recreational seawaters of southern Portugal

Three microbiological criteria (European Economic Community, World Health Organization/United Nations Environment Program and European Union) for water quality have been comparatively evaluated in a resort zone of southern Portugal, located at the Ria Formosa (Algarve). The results obtained in this study suggest that the three compared directives adequately classified the bathing zones according to their fecal pollution level. However, none of the directives establish a sanitary classification of the recreational use of the bathing zones. By the use of the Cumulative Contamination Index applied in this study, classification based on both the level of fecal pollution and on the sanitary condition of the bathing zones has been achieved. The application of this new approach to the monitoring of bathing waters allows us to propose a new criterion of water quality based on the coliphage levels (Ph-80 = 300 pfu 100 mL(-1) and Ph-95 = 2000 pfu 100 mL(-1)) for inclusion in the new water quality regulations. Coliphages have been shown to have a close correlation with the presence of pathogenic microorganisms, and with the fecal pollution levels of recreational seawaters. However, none of the microbial indicators tested ensured detection of pathogen presence.