Multivariable Risk Assessment of Swimming Pool and Spa Exposures [Poster]

The reported number of Recreational Waterborne Illness (RWI) outbreaks in the U.S. has increased from the initial reporting year in 1978.

From 2005-2006, RWI outbreaks peaked at 78 and 74% of the outbreaks were associated with treated water venues, including swimming pools and spas. The risk of ingesting pathogens during swimming in pool/spa water is influenced by four variables: swimmer behaviors (submerging head, swallowing water, etc.), pool structure (recirculation rate, disinfectant method, etc.), facility operation (chemical balance, maintenance schedule, etc.), and water contamination levels (i.e. pathogen concentrations). A comprehensive assessment that considers and combines these variables will be completed to determine the risk of contracting a waterborne disease from swimming in pool/spa water. Twelve pools and spas in Tucson, Arizona will be evaluated on structure, operation and contaminant levels by testing chemical concentrations (chlorine/bromine, pH, alkalinity and cyanuric acid) at multiple depths, assaying water samples for fecal coliform, Pseudomonas aeruginosa and heterotrophic Bacteria, and recording other relevant data. Swimmer behaviors will also be monitored using video surveillance, and swimmer ingestion rates will be quantified by comparing cyanurate concentrations in urine and pool water. The research will evaluate swimming behaviors that increase the risk of ingesting pathogens, and the influence that pool characteristics have on that risk. Data from the assessment will be modeled to determine the risk of swimming in different exposure scenarios, like lap swimming or diving, with consideration of pool water ingestion, recirculation rates, and chlorine, cyanuric acid, fecal coliform, Pseudomonas aeruginosa and heterotrophic Bacteria concentrations during the exposure period. Results from the research will be available in May, 2012.