Seine River Safe for Olympic Swimming

— Water quality data released by Paris Olympics organizers indicates that bacteria levels in the Seine River were within acceptable limits during the swimming events. The data, collected from July 19 through the marathon swimming events, shows that athletes swam in water that met established safety thresholds. This comprehensive dataset includes results from at least two tests each day across four sampling sites, providing a clearer picture of the river's condition. Despite the successful outcomes during the events, the data reveals that bacteria levels often exceeded acceptable limits, particularly following heavy rainfall. The Seine's cleanliness is significantly influenced by weather conditions, with higher bacteria levels typically recorded for three to four days post-rain. However, warm temperatures and sunlight can mitigate these levels, allowing the Olympic events to proceed as scheduled, albeit with some delays, such as the men's individual triathlon. On the day of the triathlon mixed relay, all four sampling sites reported acceptable E. coli levels, although one site, Port du Gros Caillou, showed elevated enterococci levels. This site was outside the relay course, which allowed the event to continue without issue. Under the guidelines set by World Triathlon and World Aquatics, water quality is deemed "good" if E. coli levels are below 1,000 colony-forming units and enterococci below 400 per 100 milliliters. While the data supports the safety of the events, it also highlights the potential health risks associated with contaminated water, as even small amounts can lead to infections, particularly in vulnerable populations.