Olympic triathletes swam in the Seine–but is it really safe?
Key Takeaways
Paris spent millions of dollars on water cleanup projects to disinfect the Seine River, which has long been polluted, before the Olympic games.
Recent rainfall led to a reported increase in river pollution, delaying the Olympic triathlon swim for two consecutive days.
After pollutant levels were deemed safe by Wednesday, athletes made a historical splash into the Seine.
Olympic triathletes plunged into the Seine River on Wednesday to compete in the sixth Olympic triathlon competition since the event debuted in 2000 at the Sydney Games.[] France's Cassandre Beaugrand claimed the women’s gold medal with a time of 1:54:55 and Great Britain’s Alex Yee claimed the men’s gold with a time of 1:43:33.[][] But having originally been scheduled two days earlier, the highly anticipated event made waves not just for its athletic feats, but also for its health concerns related to swimming in the Seine.
The Seine River is infamous for its polluted waters, which have been deemed unfit for swimming for more than a century, according to The Associated Press.[] While the host city took expensive measures to clean up the river before the Paris Games, weekend rainfall threatened to steal from Paris’s investments. Over the last few days, concerns have been raised about river-lurking germs such as E. coli bacteria, which can cause digestive problems and intestinal distress. Worries about the Seine’s safety prompted the triathlon to be delayed for two consecutive days until organizers deemed the water safe to swim in on Wednesday.[]
Why is the Seine River polluted?
The Seine’s historical pollution is largely due to its combined stormwater and sewer system, which can act as a passageway for untreated water to flow into the river. This can happen when the system is overwhelmed by circumstances like heavy rainfall.
In preparation of the Olympic Games, France took initiatives to clean up the river through a $1.5 billion project that involved installing a basin to catch excess rainwater and keep untreated wastewater from flowing into the river.[] City officials also upgraded and renovated various systems related to water treatment. Despite improvements, the system still appears vulnerable to mishaps during extreme weather.
E. coli contamination can be linked to human feces and appears to have entered the Seine by means of the sewage system.[]
What are the health risks associated with E coli in water?
In humans, E. coli exposure can cause health problems like abdominal pain, diarrhea or bloody diarrhea, vomiting, or fever.[] For some, it can also lead to life-threatening complications. People are most at risk of developing these symptoms if they ingest E. coli, which can happen if they eat food or swallow water contaminated with small particles of contaminated feces.[] Swimmers in contaminated water can be at risk of accidentally swallowing the germ when underwater or coming up for air, even if they are not intentionally trying to drink the water.
Treatment for E. coli infections can involve various antibiotics and may vary based on the strain a person has been infected with and the severity of their infection.
How much E. coli is in the Seine?
It’s unclear exactly how much E. coli is currently in the Seine, but, as backed by their decision to carry out the triathlon competition, organizers said that Wednesday’s levels were within quality standards, according to the Associated Press.[]
The World Triathlon Federation offers guidelines for water quality standards in triathlons, including those pertaining to E. coli levels.[] E. coli levels at or below 900 colony-forming units per 100 milliliters reflect sufficient quality for inland waters like the Seine. However, sufficient quality does not mean that water is safe enough to host a triathlon swim. The Federation recommends not organizing triathlon swims in anything other than “excellent” inland swimming water, which can contain E. coli levels at or below 500 colony-forming units per 100 milliliters.
The Federation says to cancel swims if E. coli levels are higher than those listed above, “unless the World Triathlon Medical Committee permits the Good Water Quality category.”
Now, after the triathlon, French President Emmanuel Macron is celebrating the Seine cleanup effort as a success.
Despite delays and disease risks, he wrote on X that France has “achieved in four years [what was] impossible for 100 years: the Seine is swimmable.”[]
What this means for you
Olympic athletes swam in the Seine River this Wednesday, despite recent—and historical—concerns over water pollution.