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Incidence of Somatic and F+ Coliphage at Three Great Lake Beaches
Wanjugi, P., Mano Sivaganesan, C. Kelty, A. Korajkic, E. Rhodes, B. McMinn, Mike Cyterski, K. Oshima, E. Stachler, A. Topper, L. Bertaux-Skeirik, J. Kinzelkman, M. Citriglia, F. Hsu, AND O. Shanks. Incidence of Somatic and F+ Coliphage at Three Great Lake Beaches. Water Microbiology Conference 2016, UNC Water Institute, Chapel Hill, NC, May 17 - 19, 2016.
To inform the public.
There is a growing interest for the potential use of coliphage as an alternative indicator to assess fecal pollution in recreational waters. Coliphage are a group of viruses that infect E. coli and are commonly used as models to infer the likely presence of human enteric viral pathogens. However, many uncertainties still exist concerning the application of coliphage for recreational water quality monitoring.We report the use of a dead-end hollow fiber ultrafiltration single agar overlay method to enumerate F+ and somatic coliphage from surface waters collected from three Great Lake beaches and nearby discharging rivers with historically high E. coli densities. At each beach location, three sites (two beach; one river) were sampled five days a week over the 2015 beach season (n = 580 total samples). Inaddition, E. coli and enterococci densities, as well as 16 physical, chemical, climate and beach condition parameters were assessed such as rainfall, turbidity, dissolved oxygen, pH, ultra violet irradiation and number of birds. Overall, somatic coliphage levels ranged from non-detectable (ND) to 4.39 log10 PFU/L and were consistently higher compared to F+ (ND to 2.84 log10 PFU/L), regardless of water sample. Both somatic and F+ coliphage were significantly correlated with E. coli (MPN/100mL) and enterococci (CFU/100mL) densities (p < 0.05). Distinct spatial and temporal trends in coliphage densities were apparent based on sampling site location (within and between beaches), rainfall, and occurrence of combined sewer overflow events. In addition, results indicate that some physical and chemical propertiesare more closely correlated with coliphage densities than others suggesting additional research on the development of forecasting models is warranted.