PARIS, France — After days of water-quality concerns caused by heavy rains last week put the swimming portion of the Olympic triathlons in doubt, the women dove into the Seine River on Wednesday under gray skies that lingered following an early-morning drizzle.
The athletes began near the Pont Alexandre III, a bridge that spans the famed Paris waterway. The steady rain tapered off just as the athletes splashed into the water. Some of the triathletes dunked their swim goggles in the Seine before putting them on and heading into the river with the Eiffel Tower in the background.
The decision to go ahead with the swim for the triathlon competitions was a big deal for the city, Olympics organizers and the athletes. Officials undertook an ambitious plan, including 1.4 billion euros ($1.5 billion) in infrastructure improvements, to clean up the long-polluted Seine and have been steadfast in their insistence that the swimming portion of the triathlon and the marathon swimming events next week could safely be held in the river.
The organizers said early Wednesday the latest tests of the water showed compliance with quality standards. That came after days of uncertainty following heavy rains on Friday and Saturday.
“The problem is always worse when there’s a heavy rainfall, because it kind of overwhelms the pipes and you also get all the runoff from the street. All that lands in the Seine,” explained Dr. Nicole Iovine, an infectious diseases specialist at the University of Florida. “They’ve done a lot to try to improve the quality of the water. But the truth is you're at the mercy of Mother Nature.”
As they swam, the women stayed close to the barges and boats that line the banks of the river. Spectators watched and cheered form the stands set up along the side and from the bridges spanning the waterway. Reigning Olympic champion Flora Duffy of Bermuda was the first out of the water, taking about 22 minutes to complete the 1.5-kilometer course.
After swimming two laps in the Seine, the athletes emerged from the water and ran up a set of stairs to jump on their bikes for a ride through the rain-soaked streets of Paris, including the iconic Champs-Elysees. There were numerous crashes and wipeouts along the wet roads. There were blue skies when the triathletes began the final portion of the race, a 10-kilometer run.
France’s Cassandre Beaugrand won gold in the women’s event, while Switzerland’s Julie Derron took silver and Great Britain’s Beth Potter got the bronze medal.
Elevated levels of bacteria in the river pushed the men’s race originally planned for Tuesday to Wednesday, when the women’s competition had been scheduled. The men were slated to start about three hours after the women's race. Test events meant to allow the athletes to familiarize themselves with the course had already been canceled for the same reason on Sunday and Monday.
The water quality in the Seine is directly affected by rainfall that can lead to wastewater runoff flowing into the river. Heavy rains fell during Friday’s Olympic 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 and a half 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 and 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.
