Rethinking Recreational Water Monitoring: Can predictive modelling increase public health outcomes? (50m Lecture)

 First, we will give an overview of current practices the management of recreational water in Canada, drawn from Health Canada’s Guidelines for Canadian Recreational Water Quality, as well as province- and district-specific standards and protocols from across the country. This description will include identifying the decision makers, a description of the different methods used in employing the geometric mean, and a description of current posting practices. We will put Canadian practices in an international context by comparing them with the guidelines put forth by the U.S. EPA and the WHO. Then, we will describe the challenges of enforcing standards in boundary regions where differing practices are drawn into sharp contrast for the public eye, dominating interactions with the media.

 
Next, we will review on the use of the geometric mean. The research questions include what are the limitations of using bacteriology in general, and the geometric mean of E. coli in particular, as the basis of decision-making with respect to the safety of recreational water, and what are the most appropriate, evidence-based cut-offs for values of the geometric mean for water to be considered safe or unsafe? Peer-reviewed studies of the strategies (comprehensive, geometric mean, etc.) used in the management of recreational water, peer-reviewed epidemiological studies of swimming-related gastroenteritis, as well as case reports and the results of outbreak investigations linked to recreational water use, that include information about geometric mean, and grey literature on recreational water quality criteria such as reports by governments and NGOs are considered within the scope of this review. Next, in light of our findings on the geometric mean, we will discuss the potential benefits of a comprehensive risk assessment strategy, forecasting models, and risk management approaches to posting. We will make recommendations aimed at those charged with making decisions about recreational water safety. The emphasis of the recommendations will be on the actions that can be taken to mitigate the problems that exist with the geometric mean. Possible recommendations include: the development of a forecasting model, the use of standardized posting signs, and the development of a communication plan.