Detection of Infeccious Enterovirus, Somatic Coliphages and bacterial indicators in Estoril Coast bathing waters

In this study, we aimed to determine whether Somatic coliphages (SC) and Enterovirus were good indicators to predict pathogens presence in bathing waters and if there was any correlation between them and bacterial indicators currently used (Escherichia coli (EC) and fecal Enterococci (FE)). Six beaches, two creeks and a wastewater treatment plant in Estoril Coast were sampled for the quantitative detection of these parameters. EC and FE were enumerated by Most Probable Number (MPN) (Colilert/Enterolert). SC were quantified according to ISO-10705-2:2000 and Enterovirus using BGM cells and double-layer plaque assay. EC, FE and SC were detected in all samples analyzed for these parameters whereas Enterovirus were only detected in 37% of the samples. EC MPN and SC Plaque Forming Unit PFU were highly correlated and the relationship between SC PFU and FE MPN paralled that of EC and SC. There is no correlation between Enteroviruses and bacterial indicators. However, a significant correlation between both viruses was found. A seasonal distribuition was observed in autumn with an increase in the number of EC, EF and SC. For those Enterovirus detected in wastewaters the seasonal peak occorred during autumn but for those detected in beaches the pick was found during summer. Microorganisms concentration was higher for samples collected during rainy days due to sand and land lixiviation and in the particular case of Carcavelos beach due to contamination with Marianas creek. From these preliminary results we can conclude that SC might be an interesting approach for improving water quality control regarding to pathogens.