Will the Seine be ready for Olympic swimming? With dry weather and a little luck

Being a veteran world-class swimmer — and cyclist, and runner — Taylor Spivey has dealt with worse than Paris’ River Seine.

“I’ve definitely swam in far more stagnant, questionable bodies of water throughout my career as a professional triathlete,” the 33-year-old told The Athletic via email this week.

Spivey has spent much of the last two decades swimming all over the world, becoming one of the United States’ top triathletes, finishing second in the sports’ Super League Championship Series in 2022 and fourth overall in the World Triathlon Championship Series in 2022. Before she got into triathlons, she was an award-winning member of multiple USA Lifesaving International teams and was an ocean lifeguard in Los Angeles. She’s making her Olympic debut for the U.S. mixed relay team in Paris at the 2024 Summer Games this week, after barely missing out on making the 2020 Olympic team in Tokyo.

So, she’s spent lots of days in lots of turbulent waters.

And thus the idea that the Seine may be too contaminated with E. coli and other pollutants for her and the world’s other top triathletes isn’t something she — and, likely, most of the other competitors — spend much time grousing about. There are medals at stake. So, if she and the other triathletes are allowed to do so, she’ll jump in the Seine and deal with the conditions.

“No one wants to get sick, but we also want to swim; after all, we train to swim, bike, and run,” she said in the email. “We saw this same topic of discussion leading into both the Rio (2016) and the Tokyo Olympic Games. It’s always a concern, but it also feels like the same hype we’ve seen in the past. We swam in the Seine at the Paris test event last year, and to my knowledge, no one got sick from the water quality.”

Paris has centered its iconic river as a touchpoint for the Games. The Games’ opening ceremony Friday, will, for the first time, not involve nations marching through a new or refurbished stadium in the host city, behind their nation’s flags. In Paris, the ceremonies will be held on the Seine, with boats carrying the more than 10,500 athletes from more than 200 nations down nearly four miles of the river, culminating at the city’s Trocadéro.

After the boats come out of the water, the city hopes, swimmers and triathletes will be able to go in.

The water quality of the Seine, long one of the world’s most famous and most romanticized bodies of water, where couples have strolled and occasionally danced (oh, come on: you never saw “An American in Paris?”), and along and over which so many walked, has been a central point of concern for the French government as it launched, and then spent billions to bolster, its audacious plan to make the Seine again swimmable. This, after a century of refuse, human and otherwise, made it so filthy that no one, with few exceptions, was allowed to dive in — and 124 years since the Seine was home to swimming events at the 1900 Games in Paris.

But after opening a $1.5 billion water storage basin in the city in May, and after several weeks in which there’s been little rain in the city, the Seine’s water quality has significantly improved.

Whether the upward trend holds in time for the Olympic and Paralympic competitions remains uncertain. The triathlons for men and women are on July 30 and 31, with the mixed relay on Aug. 5. The marathon swim is scheduled for Aug. 8 and 9. Para-triathletes are scheduled to swim in the Seine on Sept. 1 and 2.

Triathletes plunge into the Seine last August during a test of the course. American Taylor Spivey is among those not concerned the Seine will be suitable for swimming. (Bertrand Guay / AFP via Getty Images)

Standards for water quality differ in Europe than in the United States. The beta water limits for E. coli in the U.S. are 126 colony-forming units per 100 milliliters; in Europe, the limit is 900 units per 100 milliliters. The World Triathlon Federation says that 900 units per 100 is safe for competitions.

But if city officials deem the water is too dirty to swim in by the time of the events, Olympic organizers would try to move the competition dates back. If the Seine remained too dirty, the triathlon would eliminate the 1,500-meter swim and become a duathlon, with just the running (10km) and cycling (40km) legs. The marathon swim events would be moved to the Vaires-sur-Marne Nautical Stadium, where the rowing and canoe competitions will be held.

Like most older cities, Paris’ water supply is subject to contamination through the mixing of rainwater and wastewater in the same sewer pipe systems. When there’s no or little rain, a city’s sewer system such as Paris’ can usually keep everything separated. But when the skies open up and Paris gets hit by torrential rain, the sewers overflow. Not only does sediment and trash get washed into the Seine, but so does human waste, which leads to bacteria like E. coli developing in the water. Such bacteria would likely not be fatal if consumed by swimmers, but it could make them awfully sick.

Such an event occurred a year ago when the worst rains in six decades hit the city. The Seine’s water quality deteriorated to the point that Paris had to cancel some test events for the marathon swimming, triathlon and para-triathlon.

Yet Paris has plowed forward.

The massive storage basin, underneath the Austerlitz train station in the central part of the city, catches rainwater that might otherwise run into the Seine. Massive tanks at the basin can catch up to 20 Olympic-sized swimming pools’ worth of dirty water. The water is then sent to a treatment plant downstream from the city, through a network of underground pipes. When the bacteria has been removed from the water, it is sent back to the city and pumped into the Seine.

Paris and its surrounding areas have had much drier weather this month than in the spring. The drier conditions have helped improve the quality of the Seine significantly. But that can change in an instant.

In early July, according to Eau de Paris, the city’s monitoring metric of the Seine’s quality, two periods of rain, upstream from the city, “had an impact on water quality and flow. Despite these poor weather conditions, the water quality of the Seine reached the compliance thresholds of the European directive for 3/4 of the points monitored, over four days. At the Olympic site monitoring point, this level was reached six days (during the) week.”

And, fulfilling a long-stated pledge, Paris mayor Anne Hidalgo swam in the Seine last week to highlight that the river was clean enough for the Olympians.

Paris mayor Anne Hidalgo takes a dip in the Seine last week, hoping to ease fears about the river. Recent tests have shown pollutants within mandated levels. (Victoria Valdivia / Hans Lucas / AFP via Getty Images)

“Based on what we’ve seen the past few weeks, since about the 24th, 25th of June, we’ve seen significant increase in water quality,” said Dan Angelescu, the founder of Fluidion, a water monitoring company that has worked with the city for the past seven years to monitor the Seine’s pollution levels at multiple collection points through the river’s flow.

Fluidion’s latest measurements of E. coli in the Seine, as of Sunday, showed the Seine at 591 colony-forming units per 100 milliliters, well below the 900-unit minimum.

“So water quality has improved,” Angelescu said. “And that can be associated, on one hand, with the clement weather, dry weather. And, on the other hand, about a week before the date when we started seeing improvements, the Austerlitz capture basin, the rain and sewage capture tank, has been put in operation for the first time, and it filled for the first time. So it could be that we see a combined effect of this infrastructure being operational, and the weather.”

Paris’ issues with the Seine are not all that different from those that other, older cities around the world are dealing with in regard to their rivers and streams that flow through their cities.

“Where you have older infrastructure, and especially where you have combined sewers, this is the case with the older cities in the U.S. This is the case with Philadelphia; it’s the case with Boston, with Chicago, with New York City. The problems are the same. When you get a lot of rainfall, the sewers overflow, and it creates and combines to overflow.”

Spivey concurs.

“The biggest concern with water quality in major cities like Los Angeles, is the run-off after it rains, and only if it hasn’t rained in a while due to the buildup in the storm drains,” she said. “Otherwise, especially with flowing bodies of water, I am far less concerned when I toe the line of a triathlon.”

Angelescu said that making predictions about what the Seine will look like on Olympic race days would be folly. There are too many variables, not just the weather forecast. Overflows upstream from Paris, including illicit connections to the city’s storm water network by home and boat owners, can dump significant pollutants into the Seine with little advance notice. Wastewater plants in the area produce pollution in the river if the plants don’t disinfect their liquid waste. (Some do, but not all.)

For her part, Spivey is ready to go.

“I think safety and health should always be a concern, but there needs to be a threshold,” Spivey said. “Athletes are gritty and we are ready to take on whatever weather conditions, tough race courses and unexpected scenarios that come our way. The best athletes are often the most adaptable. Plus, we’ve trained our entire careers for this Olympic moment and to deny athletes the opportunity to complete in their true discipline would be a huge disappointment.”

In June, in an interview with the Canadian Broadcasting Corporation, Angelescu said that, given the quality of the Seine at the time, he wouldn’t be comfortable swimming in the Seine.

Would he do so now?

“I would,” he said. “I would, actually. What I answered is that, the data will tell. That was my answer. And I still say that. Today, the data looks very different from how it looked a month ago. A month ago, we, basically, we hadn’t had yet a single day where the water quality had been acceptable for the whole year. Look at our data for the past week. You see, with the exception of last weekend, where it was (affected) by a rain event, on many days, the water quality is acceptable, or close to acceptable, to world triathlon standards. So, it’s a big difference.

“It’s a bit ironic that it’s all there at the last minute. But, it’s true. We have data. Right now, probably, today, I would go swim.”

GO DEEPER

Team USA has owned the Olympic swimming pool — is that about to change in Paris?

(Top illustration: Dan Goldfarb / The Athletic; photo: Sina Schuldt / picture alliance via Getty Images)