Olympic swimmers and other athletes, Rio residents, and dolphins encounter a noxious stew of pathogens and pollutants in Brazil. Roughly 16 million people live around the bay, making it one of the world’s most densely populated urban areas. Many neighborhoods lack proper sanitation, causing squalid water conditions, including raw sewage and extreme levels of disease-causing microorganisms in Guanabara Bay. Athletes have complained the water is littered with trash, and that it irritates their skin and causes stomach ailments. Some teams have instructed Olympic rowers to avoid splashing water on each other and to carry hand sanitizer onboard their boats. All this pollution is coming from raw sewage.
Human sewage can carry a number of pathogens, including viruses and bacteria. Enteric viruses excreted in feces and found at high levels in untreated sewage are a major concern in Guanabara Bay. Also, Waterborne illnesses are a major problem for Rio residents, especially Rio’s poorest people who live near the most polluted parts of the bay and have the least access to sanitation. Eating seafood contaminated with heavy metals, industrial chemicals including PCBs, and hydrocarbons from petroleum products, also causes long-term health concern for Rio residents practicing subsistence fishing in Guanabara Bay.