Microbiological Pollution of Ria Formosa (South of Portugal)

A 24-month survey on the microbiological quality of recreational shore marine waters in three sampling stations located at Ria Formosa (South of Portugal) was conducted. The classical indicators of faecal pollution, such as total coliforms (TC), faecal (thermotolerant) coliforms (FC), faecal streptococci (FS) and somatic coliphages, as well as several physico-chemical parameters (temperature, salinity, dissolved oxygen (DO) and transparency) were determined in the sampling stations, which exhibited different degrees of faecal pollution. The relationships between faecal indicators and several pathogenic microorganisms (Salmonella, Pseudomonas aeruginosa and Candida albicans) were also established in these recreational marine zones. The results obtained indicate that none of the indicators tested may be considered as a universal index of the presence of pathogens in water; however, faecal streptococci showed a higher and significant relationship with sewage discharges.