Abstract
The relationships between number of coliforms, fecal coliforms, E. coli, fecal streptococci, location, time and seasonal factors in marine environments of northwest Greece were investigated over a period of 4 years. Research focused on measuring and comparing bacteria in coastal marine waters undergoing heavy bacterial charge during the tourist season. Microbiological pollution was increased during the summer period. Seasonal fluctuation of the fecal indicator bacteria was noted and concerned mainly E. coli and fecal coliforms, which are the most sensitive indicators in the marine environment.