PARIS (AP) — Paris Olympics With less than two weeks to go until the Olympics begin, one question looms: Will the Seine be clean enough for the athletes to swim in?
The triathlon and marathon swimming will take place in the Seine, where swimming has been banned for over a century. The city has been trying to clean up the long-polluted river, but in recent weeks the river's water has been deemed unsafe for humans and on other days the water has been found to be cleaner. The events will run from July 26 to August 11.
To clean up its rivers, Paris has spent 1.4 billion euros ($1.5 billion) building infrastructure to capture more stormwater when it rains, including bacteria-laden sewage that can wash into the rivers during heavy rains and make them dangerous for swimming.
FILE – A man walks through the Austerlitz wastewater and stormwater retention pond during the inauguration of the pond, which aims to make the Seine swimmable during the Olympic Games, in Paris, May 2, 2024. (Stephane de Sactin/Pool photo, File via The Associated Press)
In May, Paris authorities open huge underground reservoir The reservoir, located next to the Gare d'Austerlitz station, aims to collect excess storm water and prevent wastewater from flowing into the Seine. The reservoir can hold the equivalent of 20 Olympic swimming pools' worth of wastewater, which will then be treated. Not only is it the centrepiece of a major infrastructure improvement that the city of Paris is rushing to complete in time for the Olympics, but it also aims to ensure that Parisians enjoy a cleaner Seine in the future.
But several heavy rains could push E. coli levels above the 900 colony-forming units per 100 millilitres limit set by the World Triathlon Federation as safe for competition.
“The Seine is not an isolated case,” said Metin Duran, a professor of civil and environmental engineering at Villanova University who studies stormwater management. “It's a really complicated and very expensive problem.”
Paris, like many older cities around the world, has a combined sewer system, meaning the city's wastewater and stormwater run through the same pipes. During heavy or prolonged rains, the pipes reach their capacity, meaning untreated wastewater flows into rivers instead of treatment plants.
The monitoring group Hauts de Paris tests the river's water every day. Results in recent weeks indicate unsafe levels of E. coli This was followed by further improving results in early July.
Paris Olympic organizers say they will consider whether to stop heavy rains from affecting the flow of the Seine during the Games. There's no swimming portion in a triathlon. The marathon swimming event will be moved to the Vers-sur-Marne Maritime Stadium in the Paris metropolitan area.
FILE – Athletes swim in the Seine River during the first leg of the women's triathlon test event for the Paris 2024 Olympics, in Paris, Aug. 17, 2023. 2024. (AP Photo/Michel Euler, File)
“It's not a common occurrence, but it has happened a few times,” Olara Cernuda, communications director for World Triathlon, the sport's international body, said of the possibility of swimming being cancelled.
“And that's always tied to water quality issues,” Cernuda said.
But organisers are optimistic that the event will go ahead as planned, despite the headaches of upgrading infrastructure, thanks to drier, sunnier weather than the French capital experienced in June – the sun's ultraviolet rays kill bacteria such as E. coli in the water.
An analysis of weather data by The Associated Press found that Paris will see its second-most rainy days in 2024 since 1950, surpassed only by 2016.
Importantly for the Seine's water quality, there were very few days without rain.
The analysis found that while Paris only experienced a week-long dry spell in early June this year, between 1950 and 2020 it was common for the city to experience at least three such periods by the end of June.
FILE – A worker walks through a tunnel leading to construction of a water tank for the Seine River in Paris, Nov. 29, 2023. (AP Photo/Aurelien Morissard, File)
“Rainfall predictions have gotten much more accurate up to a week in advance,” said Jennifer Francis, a scientist at the Woodwell Climate Research Center in Massachusetts, “but the seasonal patterns of the past few decades are no longer a reliable guide in a warmer world.”
As the Olympics approach, the fierce debate over the Seine's cleanliness has been a source of frustration for some athletes, such as French triathlete Léonie Périot, who won a bronze medal at the 2020 Tokyo Olympics.
“Every time I meet someone, they are worried that I'm going to swim in the Seine,” Pelliot said, “but I've been swimming in the river for years. I swam there regularly in youth competitions and had no problems.”
Last year, Pelliot took part in a test event on the Seine.
“The views were amazing with the Eiffel Tower in the background and the water conditions were no worse than anywhere in the world,” she said.
FILE – A boat sails on the Seine River near the Eiffel Tower during a rehearsal for the opening ceremony of the Paris 2024 Olympic Games in Paris, June 17, 2024. (AP Photo/Thomas Padilla, File)
On Saturday, French Sports Minister Amélie Oudea-Castella I took the plunge The mayor of Paris, Anne Hidalgo, has also said she will swim in the Seine this week to show that the river is clean enough.
Although water quality in the Seine has improved since the city's new infrastructure went online, it remains vulnerable, said Dan Angelescu, founder and CEO of Fluidion, a Paris- and Los Angeles-based water-quality monitoring technology company that has been measuring pollution levels in the river for several years.
Angelesc said it was difficult to use historical data to predict what would happen later this month because reservoirs and other infrastructure were not operational until several months ago.
“It's difficult to tell,” Angelescu said in early July after tests of the Seine's water quality showed it was cleaner than a few weeks ago.
“To see such dramatic improvements so quickly could be a sign that something is going well,” he said.
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Associated Press writer Mary Katherine Wildman contributed to this report from Hartford, Connecticut. Nishadam reported from Washington.
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