• Coliphage as an indicator of the quality of beach water to protect the health of swimmers in coastal Georgia

      Gallard-Gongora, Javier; McGowan Mark, Kathryn; Jones, Jeff; Aslan, Asli; Georgia Southern Universit (Georgia Public Health Association, 2017)
      Background: Gastrointestinal disease affects millions of people in the United States and places a substantial economic burden upon healthcare systems. Recreational waters polluted with fecal material are a main source for transmission of gastrointestinal disease. Georgia beaches are monitored for the presence of fecal indicator bacteria, but these bacteria are not well associated with enteric viruses. The United States Environmental Protection Agency (US EPA) has recently proposed coliphage (a virus of Escherichia coli) as an alternative indicator of fecal contamination in recreational waters. The present study compares fecal indicator bacteria and coliphage concentrations at two Georgia beaches with adjacent creeks that have a history of pollution. Methods: For one year, samples and environmental data were collected from four sites on Jekyll Island, GA, during the peak swimming season and the off-season. Samples were processed using US EPA-approved methods for membrane filtration and plaque formation. Statistical analyses were performed using t-tests and Spearman correlations. Results: The highest numbers of enterococci and significant differences with coliphage were found at Saint Andrews Creek during the swimming season and the off-season. The enterococci concentrations at Clam Creek sites did not exceed recommended recreational water criteria. During the off-season, concentrations of enterococci and coliphages were different at Clam Creek sites, indicating a potential risk for presence of enteric virus when enterococci could not be detected. Conclusions: The US EPA has proposed to adapt coliphage concentrations as an alternative indicator of water pollution for routine beach monitoring nationally. The present study provides a background for adoption of this method in Georgia. Measures of enterococci do not provide sufficient information about the associated human health risk. Inclusion of these viral indicators will improve decision making for beach closures and for protection of the health of swimmers.
    • New recreational water quality criteria and their impact on beach advisories in Coastal Georgia

      Aslan, Asli; Benevente, Sara; Georgia Southern University (Georgia Public Health Association, 2016)
      Background: To monitor pollution of marine beaches in Georgia, enterococci have been used as indicators of fecal contamination. For the 1986 Recreational Water Quality Criteria (RWQC), the beach action value (BAV) was 104 colony-forming units (CFU)/100 ml; the new RWQC, instituted in 2012, is 70 CFU/mL, a 32.6% decrease. When the beach action value is reached, authorities are to issue a beach advisory for protection of swimmer health. The present study investigated changes in compliance with the 2012 RWQC at five high-use beaches in Georgia. Methods: In the summer of 2015, samples of water were collected from five beaches at Tybee Island. Enterococci concentrations were enumerated by USEPA-approved methods. Samples exceeding the 1986 and 2012 RWQC beach action values were compared with times that advisories were posted at these beaches. Results: At these beaches, advisories were posted four times during the summer. Since, in 2015, the previous RWQC was in use, these decisions were based on the guideline value of 104 colon-forming units (CFU)/100 ml. When the new beach action value (70 CFU/100 ml) was applied, retrospectively, for samples collected at these sites, we found that the number of advisories would have been doubled if this value had been in place at that time. Conclusions: Staring from January 2016, Georgia has adopted new water quality criteria to monitor beaches. Decreasing the beach action value to 70 CFU/100 ml strengthens beach monitoring programs because it allows for better prevention from waterborne diseases, thus protecting the health of swimmers.