Seasonal variations of microbiological parameters of water quality of the Velika Morava river Serbia

In this study, we investigated the level of sanitary pollution and organic contamination of the Velika Morava River, the largest river in central Serbia. Samples of water for microbiological analysis were collected at 5 sites, monthly, from April 2010 to February 2011. Sanitary analysis, i.e. enumeration of total and fecal coliforms and intestinal enterococci, indicated moderate to critical fecal contamination, while organic load assessment (oligotroph to heterotroph ratio, index of phosphatase activity) revealed the category of moderately polluted water. We also investigated seasonal variations of these groups of bacteria and the factors that could contribute to these differences. Our results showed that the micro- biological quality of the water in the Velika Morava River during different seasons is affected by numerous factors such as unequal loading of wastewaters, solar irradiation, and relations of flow/dilution and rainfall/runoff. [Acknowledgments. This study was financially supported by the Ministry of Education and Science of the Republic of Serbia: projects No 173025, No 177045 and No 043002.]