PARIS — A test run to familiarize Olympic athletes with the marathon swimming course on the Seine River was called off Tuesday over concerns about the water quality in Paris’ waterways.
World Aquatics said in a statement that the decision to cancel the exercise had been made at an early morning meeting.
With both the triathlon and marathon swimming events due to take place in the river during the Games, fluctuating bacteria levels in the long-polluted waterway were a constant concern.
Another test event, the marathon swim, is scheduled for Wednesday, with organisers to decide whether to go ahead earlier in the day, the statement said. The women’s marathon swim is scheduled to take place on Thursday, while the men’s race is scheduled for Friday.
The cancellation of Tuesday’s marathon swimming test event came a day after a mixed triathlon relay event was held on a river through the center of the French capital.
The World Triathlon Association released data Tuesday showing that fecal bacteria levels of E. coli and Enterococcus faecalis were within acceptable limits for the length of the triathlon’s relay course when triathletes swam on Monday.
Both the triathlon swim and the marathon swim start and finish at Pont Alexandre III, but the marathon swim course continues further down the river. Marathon swimmers complete six laps of a one-mile course for a total of 6.2 miles.
Water samples taken early Monday showed E. coli levels ranged from “good” to “very good” at four sampling points in the river, according to World Aquatics. Because it takes time to culture enterococci samples, the decision to halt Tuesday’s test run was based on samples taken on Sunday.
Levels of enterococcus bacteria from Monday, available by Tuesday morning, showed the river’s water quality was improving, though one in four tests was still below the World Aquatics Standards. Organisers, however, said they “remain confident” the marathon swim will go ahead on the Seine as scheduled, based on a “favourable weather forecast and forward-looking analysis”.
That confidence was echoed by Paris Mayor Anne Hidalgo, who made headlines last month after swimming in the Seine to ease concerns about water quality ahead of the Olympics.
“Obviously we’ll wait until we get the results of the water tests, but the weather has definitely improved over the last few days so the event will go ahead,” she said. “So I’m really proud and happy, and to those who continue to say it’s impossible to decontaminate the river I want to say, ‘Yes, it’s possible, and we’ve done it.'”
2024 Paris Olympics
With a few exceptions, swimming in the Seine has been banned since 1923 because the water is too toxic. Paris has embarked on an ambitious plan to spend 1.4 billion euros ($1.5 billion) on infrastructure improvements to allow it to host some swimming events on the river, including building huge reservoirs to capture excess stormwater and prevent sewage from washing into the river, renovating sewer infrastructure and upgrading wastewater treatment plants.
The Seine’s water quality is closely linked to the weather: heavy rains can dump sewage and runoff into the river, raising bacteria levels, while warmer temperatures and the sun’s ultraviolet rays can kill the bacteria.
The weather was mostly hot and sunny throughout the event, with several days of heavy rain. Water quality concerns led to the cancellation of the test swim in the Seine prior to the individual triathlon and mixed triathlon relay events, and the men’s individual triathlon was postponed by a day.
Of the more than 100 triathletes who took part in the men’s and women’s individual events last week, four fell ill within days of the event, but it is unclear whether the water was to blame.
