Male Specific Coliphages as an Indicator of Fecal Contamination of Drinking Waters and as Model Organisms for the Reduction of Viruses by Water Treatment Processes
This study field-tested a new membrane filter method (MF) for the enumeration of F-specific RNA coliphages in source waters and treated drinking waters to assess the potential use of these organisms as a viral indicator. Simultaneous testing for F-specific coliphage by the Single Agar Layer Method (SAL) as well as for E. coli and enterococci permitted comparisons between the two phage detection methods as well as the evaluation of F-specific coliphages as an indicator of fecal pollution. Mean concentrations of coliphages enumerated by the SAL and MF methods were comparable and correlation analysis resulted in a Pearson's correlation coefficient of 0.85. F-specific phages were reasonably well correlated with both bacterial indicators as well as with the presence or absence of upstream, permitted, wastewater discharges suggesting the usefulness of these coliphages in assessing fecal contamination of natural waters. The reduction of F-specific coliphages by water treatment processes was observed at four drinking water treatment facilities. No phages were detected in any of the treated, or partially treated samples. Coliphage reductions of up to 5 logs were observed with an average reduction of >3.3 log[10]. Source waters were found to contain a mixed population of Somatic Salmonella phages as well as the F-specific coliphages. The presence of these phages interferes with the relationship between the F-specific phages and the human enteric viruses. This study demonstrates the applicability of the membrane filter method to natural waters and the usefulness of F-specific coliphages as an indicator of fecal contamination. Further modifications in the host bacterium may be required to compensate for the interference by somatic Salmonella phages.Master of Science in Public Healt
