Occurrence and predictive correlations of Escherichia coli and Enterococci at Sandpoint beach (Lake St Clair), Windsor, Ontario and Holiday beach (Lake Erie), Amherstburg, Ontario

Abstract

Point and nonpoint sources contribute to fecal contamination of surface waters by human pathogens that exist at low concentrations and are difficult, expensive, and/or impossible to easily detect. Therefore, fecal indicator bacteria (FIB) are used as surrogates in identification of fecal contamination, including Escherichia coli (EC) and Enterococcus spp. (ENT), at recreational beaches to protect from adverse health effects from exposure to water-borne pathogens. The objective of the current study was to conduct a preliminary investigation of the environmental processes contributing to the nature and significance of FIB (EC and ENT) over 30 d at Sandpoint beach (Windsor, Ontario) and Holiday beach (Amherstburg, Ontario). Daily, three 100 mL samples were collected for EC and ENT for analysis by Colilert® and Entrolert®, respectively. Additionally, physicochemical and hydrometerological data were measured or taken from data archives. Both EC and ENT populations were dynamic and well correlated to each other (p < 0.05; analysis of variance (ANOVA)) and both FIB correlated with turbidity and wave height (p < 0.10; ANOVA). Despite being geographically close and therefore having similar meteorological data, both beaches exhibited markedly different FIB, turbidity and wave height data, suggesting that beach-specific data should be considered for any future predictive applications.