Will the River Seine be ready for Paris’ 2024 Summer Olympics?

One of the biggest questions leading up to this summer Olympics in Paris — the opening ceremonies begin on July 26 — isn’t just who’ll be bringing home the gold but whether the River Seine, the iconic epicenter of Paris culture and history, will live up to its expectations during the games.

On one end of the controversy, there are the Paris Olympic officials, who are unwaveringly optimistic. Organizers have long insisted there is “no plan B” for the open-water swimming events taking place in the Seine, which include a portion of the triathlon, a mixed-team relay race, and the 10,000-meter. Christophe Dubi, the International Olympic Committee’s executive, said in June that he had “no reasons to doubt” that the Seine will be clean enough for swimming, and Paris Mayor Anne Hidalgo boldly declared, “We are going to make it despite all the skepticism.”

Last Saturday, French sports minister Amélie Oudéa-Castéra took a dip in the Seine to prove it was safe, while this past week Hidalgo herself took a dip to placate critics.

Bill François, a marine scientist with the Paris Fishing Federation, told The Post that anti-Seine sentiment is “political propaganda. It’s all fake suspense to attract attention. Of course it’ll be OK.”

On the other end of the argument, there are the dubious athletes and microbiologists. “I’m not optimistic that the Seine will be safe enough for swimming,” says Bill Sullivan, Ph.D, a professor at the Indiana University School of Medicine who studies infectious diseases. Detection of E. coli in the river “means there is literally poop in the water—either from human sewage or soil erosion from farms that may have infected animals.”

Ana Marcela Cunha, the Brazilian swimmer and reigning Olympic open-water champion, told the French press that the river is “not made for swimming.” And first-time Olympian Ivan Puskovitch, set to compete in the 10K marathon swim event, said the question of whether the Seine will be ready is his “biggest concern.”

Some critics are doing more than just complaining. A protest organized by Parisians vowed to “s–t in the Seine” on June 23, the same day that Hidalgo and French president Emmanuel Macron planned a press conference. The protesters’ beef isn’t with a clean river but the local government sinking billions — $1.5 billion and counting —into making the Seine Olympic-ready while ignoring more pressing domestic issues.

All this hand-wringing isn’t much ado about nothing. The Seine is more than a venue, it’s the centerpiece of the Paris Olympics, a reminder of the city’s greatness and its connection to Olympic history (they last hosted the games a hundred years ago.) The Seine will be the star of the opening ceremony on July 26th, with a parade of 200 Olympic delegations on more than 80 boats, in an act of grand pageantry that passes Paris landmarks like the Notre-Dame and the Louvre. The river is so important to the festivities, it’ll be protected with ballistic glass and 35,000 French police and 10,000 French military guarding the athletes on both sides.

But will the Seine be clean enough by the time the Olympic torch makes its way into the City of Light? Or like Russia, will it be banned from the historic games?

The decision may come down to a photo finish. City officials in Paris regularly test the river’s E. Coli levels, and for the majority of June (22 out of 30 days), levels were too high, sometimes 10 times over acceptable limits. (According to the World Triathlon Federation, a safe limit is 900 colony-forming units per 100 milliliters of water.) The levels were better in July, but whether it remains that way “will ultimately be determined by the weather,” says Jay Famiglietti, a professor at Arizona State University specializing in sustainability and global water risk. 

Heavy rains mean more bacteria will wash into the river from urban runoff, and cooler temperatures and lack of sunshine means less bacteria will be killed off. “Organizers will be in ‘wait and see’ mode,” says Famiglietti.

Sanitizing the Seine isn’t a new endeavor. Swimming in the Paris river has been prohibited since 1923—trespassers are fined 15-euro (roughly $16) — but politicians have been promising to return the Seine to its former glory for decades. In 1988, Paris mayor Jacques Chirac pledged to “bathe in the Seine in front of witnesses” to prove cleaning efforts had worked. (He never fulfilled that promise.)

A more serious effort, Paris’s plan baignade (swimming plan), launched in 2015, with the goal of fixing the city’s sewer infrastructure, which hadn’t been updated since the 19th century. The 2024 Games were used as “a peg with which to get the political and financial buy-in to clean up the river,” says Dr. Lindsay Sarah Krasnoff, a historian who teaches at NYU’s Tisch Institute for Global Sport. “Without this motor driving clean-up efforts, I doubt that we would be discussing the possibility of swimming in the Seine.”

But despite the huge investment, the results have been underwhelming. Because of poor water quality, several Olympic “test” triathlons were canceled last summer “to protect the health of the athletes,” according to a statement from local officials.  In May, the Austerlitz water basin was unveiled, a newly-designed underground storage tank capable of holding 13.2 million gallons of rain and sewage water, the equivalent of 20 Olympic-sized swimming pools. The goal is to keep the sewer system from being overloaded, and treat the water so it’s less dangerous if (or when) it empties into the river.

It’s worked . . . except when it hasn’t, particularly after heavy rains. And even low E. Coli levels “provide no definitive information about other dangerous germs potentially lurking in the water,” says Sullivan. Including parasites like Cryptosporidium and Giardia, which “can cause vomiting and severe diarrhea.”

There are also rats — who outnumber human Parisians two to one — who urinate in the river and spread a disease called leptospirosis. “Most people will be fine if they get inoculated,” says François. And more disturbingly, piranhas. In 2013, a Parisian fisherman caught a Pacu, a cousin of the piranha, in the Seine. The fish is also known as a “ball cutter” because of its tendency to bite the testicles of swimmers.

These dangers haven’t stopped some people from swimming anyway. Joel Stratte McClure, a 75-year-old American swimmer, jumped in the Seine on July 4, and told The Post he had “no ill effects.” He also witnessed no dead fish, “nor did I see any floating garbage, sewage, dead bodies, or E. coli.” He did note, however, that his son told him post-swim, “You smell pretty bad.” (The French media were not amused, claiming McClure was lucky not to be arrested or hospitalized.)

Others haven’t been so lucky. When Gaelle Deletang, a member of the French capital’s aquatic civil defense team, went swimming in the Seine last winter, she reportedly got, in her words, “diarrhea and a rash.” Arthur Germain, the Paris mayor’s son, swam all 483 miles of the Seine in 2021, and encountered “zones where I had trouble breathing.”

The last time the Seine was still welcoming to professional athletes was during the 1900 Paris Olympics, when Australia’s Freddie Lane won two swimming events — the 200-meter freestyle and the 200 meter obstacle race (in which he had to climb over and swim under boats) — in the iconic river. Swimming moved to landlocked pools for the 1908 London Olympics, but open water made a comeback in 2000, when the triathlon debuted at the Sydney Olympics. The 10K marathon swim in open water was added in 2008.

But Paris isn’t the first time that open water has brought potential dangers. Though Rio de Janeiro made grand declarations to clean up Guanabara Bay in time for the 2016 Olympics, one doctor warned that visiting athletes “will literally be swimming in human crap.” And during the 2021 Olympic Games in Tokyo, athletes complained that the bay “smells like a toilet.”

François, however, isn’t concerned about the potential for bad press. He’s more upset that the Parisian government has “spent more than a billion for a few minutes of swimming competition,” he told The Post. “They put all the effort into tackling this stupid E. coli threshold bacteria, which has no importance for the environment.”

He points out that there were just three species of fish in the Seine during the 1960s and ’70s, “but today, we have about 40. If politicians put even a little percentage of money into biodiversity issues, tackling pollutants that aren’t bad for swimmers, my God, we would be fishing for salmon in the Seine today.”

Still, Krasnoff says the Seine has more meaning to Paris than just aquatic life. “It’s akin to a beating heart of the city,” she says. “It symbolizes the connections between the past and the present. So in many ways, the Seine is part of the city’s lifeblood, a pathway to the future — and the ocean — even as it remains at times steeped in yesteryear and reminds locals and visitors alike of the cultural heritage around them.”

The Seine may symbolize the legacy that Paris wants to present at the Olympics, but if they aren’t careful, that legacy may not be what they hope. “If the weather stays sunny and dry, there’s a chance the fecal bacteria levels will fall into the safe range,” says Sullivan. “But in the Olympics between humans and germs, the germs usually win.”