Olympic triathletes swim in Seine River after days of concerns about water quality
The water quality in the Seine is directly affected by rainfall that can lead to wastewater runoff flowing into the river. Heavy rain fell during Friday’s opening ceremony, and rain continued for most of the day Saturday.
Every day since Sunday, even as organizers announced cancellations or postponements, they continued to express confidence that the swims in the Seine would go forward as planned the next day. For several days they did not publicly release the data on levels of E. coli and other bacteria that contributed to their decisions.
High levels of E. coli in water can indicate contamination from sewage. Most strains are harmless and some live in the intestines of healthy people and animals. But others can be dangerous. Even a mouthful of contaminated water can lead to diarrhea, and the germ can cause illnesses such as infections in the urinary tract or in the intestines.
Daily water quality tests measure levels of the fecal bacteria E. coli. World Triathlon’s water safety guidelines and a 2006 European Union directive give a range of E. coli levels from “excellent” to “sufficient.” Anything beyond 900 colony-forming units per 100 milliliters is not considered safe or “sufficient.” But experts stressed that these numbers are simply guidelines used to assess risk.
Plus, Aurélie Merle, the Paris 2024 director of sports, told reporters Tuesday that water samples are taken 21 1/2 hours before decisions are made about the swim. That leaves uncertainty about their accuracy the day of the race.
Merle said Tuesday that testing results showed “we’re very close to the threshold of triathlon.” She noted that one of four test sites along the triathlon course was below the threshold for E. coli. Two other sites were just above the limit and one was more elevated, she said, citing a range of 980 to 1,553.
“We know the sun and the heat have a very strong impact on the quality of the water,” she said, hoping that a heat wave that hit most of France on Tuesday would help improve water quality.
Organizers have said the marathon swimming races, scheduled for Aug. 8-9, could be relocated, if needed, to the Vaires-sur-Marne Nautical Stadium in the greater Paris region, which already hosts rowing and canoeing competitions and can accommodate up to 15,000 spectators.