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Recreational water exposures and health effects at a tropical and a runoff impacted beach
Citation:
WADE, T. J. AND A. P. DUFOUR. Recreational water exposures and health effects at a tropical and a runoff impacted beach. Presented at National Beaches Conference, Miami, FL, March 15 - 17, 2011.
Impact/Purpose:
Methods: Beachgoers were enrolled and upon leaving answered questions regarding swimming exposures. Ten to twelve days later they were asked about new illness symptoms. Six water samples were collected three times a day and tested for fecal indicator bacteria.
Description:
Background: Studies conducted by the EPA at beaches with nearby treated sewage discharges established associations between gastrointestinal (GI) illnesses among swimmers and measurements of fecal indicator bacteria, Enterococcus and Bacteroidales (marine beaches only) measured by quantitative Polymerase Chain Reaction (qPCR). In 2009, EPAconducted studies at one beach in a tropical climate (Puerto Rico) and a second beach influenced by "urban runoff" (South Carolina). The goal was to examine water quality and illnesses among swimmers. Methods: Beachgoers were enrolled and upon leaving answered questions regarding swimming exposures. Ten to twelve days later they were asked about new illness symptoms. Six water samples were collected three times a day and tested for fecal indicator bacteria. Results: At the Puerto Rico beach 15,726 individuals were enrolled. Swimmers reported higher rates of rash. Densities of fecal indicator bacteria were low and no single day exceeded EPAcriteria for Enterococcus. In addition, the qPCRassay showed evidence of interference or inhibition. Consistent health relationships between fecal indicator organisms and swimming-associated illness were not established. At the South Carolina Beach, 11,159 individuals were enrolled. Swimmers reported higher rates of rash, GI illness and earache. Only one day exceeded EPA criteria for Enterococcus. Consistent health relationships between fecal indicator organisms and swimming-associated illness were also not established. Conclusions: At a tropical beach and a beach impacted by urban runoff, associations between illnesses among swimmers and water quality were not established. Potential explanations include better than expected water quality, qPCR interference or inhibition, and lack of human fecal contamination. This is an abstract of a proposed presentation and does not necessarily represent EPA policy