Swimming Exposure

As recognition of the risks of swimming in polluted waters grows, so does the body of evidence to support better monitoring and management of water quality. Yet most places remain unmonitored or have poor notification systems in place to protect swimmers. (Check out the safety of your beach with the Swim Guide app.) Studies like the “Beach Bum Survey” which looks at the impacts of water quality on the surfing community in different parts of the world, work to highlight this need. The survey found that surfers in the U.K. are three times more likely to be colonized by antibiotic-resistant bacteria like E. coli — because of increased exposure — than are swimmers and other recreational water users (Leonard et al., 2018). Antibiotic-resistant strains of bacteria are becoming more common for a host of reasons, including poor hygiene and sanitation. In addition to gastrointestinal infections, swimmers exposed to polluted waters are at risk for chest, ear, eye, and skin infections, as well as hepatitis. Karenia brevis, the marine dinoflagellate that causes red tides, a type of harmful algal bloom, produces brevetoxins that can aerosolize. These toxins have been associated with increased incidence of asthma, and a 40% increase in emergency room admissions for gastrointestinal disease during red tide events (Fleming et al., 2007; Kirkpatrick et al., 2010).