Olympic triathletes swim in Seine River after days of concerns about water quality

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 early Wednesday, followed by the men a few hours later.

The athletes began near the Pont Alexandre III, a bridge that spans the famed Paris waterway. The women's race began under a gray sky, with steady rain tapering off just as the athletes splashed into the water. Some 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 rain 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 triathletes stayed close to the barges and boats that line the banks of the river. Spectators watched and cheered from the stands set up along the side and from the bridges spanning the waterway.

After swimming two laps in the Seine, a 1.5-kilometer course, 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.

During the women's race, the biking portion saw numerous crashes and wipeouts along wet roads, but skies were blue by the time the triathletes began the final leg of the race, a 10-kilometer run. By the time the men's race started, the sun was beating down.

Cassandre Beaugrand of France won gold in the women's event, while Julie Derron of Switzerland took silver and Beth Potter of Britain got the bronze medal. Alex Yee of Britain won gold in the men's race, with Hayden Wilde of New Zealand winning silver and Léo Bergère of France taking bronze.

Paris organizers couldn't contain their delight that their gamble of holding Olympic events in the long-toxic river was paying off, with the astounding scenes of athletes swimming in the Seine's waters.

The massive infrastructure investment to better manage wastewater has paved the way for Paris' ultimate goal: allowing Parisians to enjoy the waterway again after more than a century of it being off-limits, with plans to open public pools in its waters from 2025.

"It's magic," said chief Paris Games organizer Tony Estanguet, speaking to French television. "It's a very important legacy for Parisians to be able to swim from next year in the Seine."

Paris Mayor Anne Hidalgo, who took a much-publicized dip in the Seine two weeks ago along with Estanguet and others to ease fears about water quality, said after Beaugrand won the first Olympic gold in the river: "How special to see her swimming in the Seine, thank you for making us so proud!"

"I wasn't very worried about the Seine River because we swam last year and no one was sick after that, so I was confident we could swim today and it would have been a shame if we didn't," Beaugrand said. Olympic triathletes participated in a test event in the river last August.

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 women began their race at 8 a.m., while the men started at 10:45 a.m. 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 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.