Olympic cleanup: Swimming in the Seine

As part of the Paris 2024 Olympic and Paralympic Games, several competitions will take place along the river Seine, setting off from the Alexander III Bridge, including the triathlon, as well as the mixed relay and open water swimming competitions.

“It's not madness, it's an ambitious goal,” said Pierre Rabadan, Paris’s deputy mayor in charge of sports. The city is confident it can reach safe water levels in time, arguing the quality has already improved. 

Tests were carried out last summer at locations that will be hosting Olympic events over a period of 15 days, the same duration of the Games. According to authorities, over 92 percent of the time, results showed water quality standards either satisfactory or excellent.

“International safety and health requirements will be met here in Paris and the water quality will be just fine,” Rabadan added. 

It is certainly an ambitious goal, and one that comes with a steep price tag: €1.4 billion over eight to 10 years.

“Without the games, we probably wouldn't have made it. Or maybe in 30 or 40 years we could have achieved what we have done in eight to 10 years.”

Even though Paris has made the Seine its leading star in the upcoming Olympics, not many people would actually brave its murky waters just yet. The iconic river has built a filthy reputation as a dump yard for all sorts of trash: plastic, cigarette butts and even electric scooters and bicycles. Some 350 tonnes of waste are hauled out of the Seine every single year. 

But it will take more than that to clean up the Seine. 

Jean-Marie Mouchel, a hydrologist and researcher at Sorbonne University, takes regular water samples to measure fecal bacteria levels present in the water.

“Fecal bacteria are not