Playing in Sewage? ... Why Focus Has Shifted to the Seine River Water Quality [Paris Olympics]

Triathlon Swimming and Open Water Swimming Events Scheduled
Paris Invested 2 Trillion Won to Improve Water Quality
E. coli Levels Exceed Competition Standards by 10 Times
Weather Is Key... Heavy Rain May Increase Flow and Worsen Water Quality

On the 17th of last month (local time), ahead of the 2024 Paris Olympics, Paris Mayor Anne Hidalgo, dressed in a black swimsuit, personally jumped into the Seine River. This was a kind of trial swim conducted to check the water quality as the Olympic and Paralympic Games plan to hold the triathlon swimming event and the open water swimming marathon in the Seine. Receiving applause from about 100 public officials, local residents, and athletes, Mayor Hidalgo smiled brightly in the water and expressed, "It is a dreamlike day. Sweet and marvelous. The result of much effort."

On the 17th (local time), Anne Hidalgo, the Mayor of Paris, smiles brightly after swimming in the Seine River in Paris, France.
[Photo by Reuters]

On the 17th (local time), Anne Hidalgo, the Mayor of Paris, was swimming in the Seine River in Paris, France.
[Photo by AP Yonhap News]

The event was held after being postponed twice before. Before the trial swim, a water quality test was conducted first to check if the water was harmful to humans, but in the previous two attempts, the water quality did not meet the standards. Mayor Hidalgo recalled, "I remember when we started the campaign to host the 2015 Olympics, the International Triathlon Union asked why triathlon events were not held in the Seine," adding, "If athletes ask whether they can swim in the Seine, I will now say yes."

This move by Mayor Hidalgo reflects the core value of the Paris Olympics, which has emphasized an 'eco-friendly Olympics.' France has put environmental friendliness at the forefront of its Olympic bid and declared as part of its pledge that swimming events would be held in the Seine. However, if the water quality does not meet the standards on the day of the event, the schedule may be postponed, or in the worst case, the swimming portion of the triathlon may not be held at all. The world's attention is focused on the water quality of the Seine.

The Seine is a 776 km-long river running through the center of Paris, similar to the Han River in Seoul. Before the construction of railroads in France, it was used as an important inland waterway.

Seine River in Paris, France [Photo by AP Yonhap News]

In the past, swimming was possible in the Seine, but from 1923 until recently, swimming was prohibited due to the risk of water pollution. Paris has a combined sewer system where rainwater and sewage share the same pipes, making the river's water quality unsuitable for swimming. Various debris such as rusty washing machines and bicycles would come out of the water. As a result, for over 100 years, only tourist and cargo ships have navigated the Seine. Former President Jacques Chirac, who was mayor of Paris in 1988, promised to clean the Seine and declared in 1990 that "we will swim in the Seine in three years," but this was not fulfilled.

After the Olympic hosting was confirmed, the French government and the City of Paris invested 1.4 billion euros (about 2.12 trillion KRW) to build infrastructure for water quality improvement. Various projects were carried out, including modernizing sewage treatment facilities, and considering that heavy rain significantly worsens water quality, a large underground reservoir was constructed nearby in May. Paris has even planned to create four public swimming pools in the Seine starting next year as part of the Olympic legacy.

However, concerns continue that the Seine's water quality is not yet at a level suitable for holding the Olympics due to various bacteria. Water quality tests conducted on samples taken from the Seine between May 18 and 20 last month found E. coli levels more than ten times higher than the standards set by the International Triathlon Union, and enterococci levels were also found to be harmful to humans. This was due to frequent rain in Paris last month, which caused sewage and wastewater to flow into the Seine.

According to the European Union's 2006 water quality directive, E. coli must be detected at no more than 900 CFU (colony-forming units) per 100 ml, and enterococci at no more than 330 CFU per 100 ml for swimming to be allowed. The World Aquatics Federation's water quality standards set the maximum allowable E. coli at 1000 CFU per 100 ml and enterococci at 400 CFU. Swimming in water exceeding these standards poses risks of gastroenteritis, conjunctivitis, otitis externa, and skin diseases.

[Image source=AFP Yonhap News]

Although the French government and Paris have made efforts to improve the Seine's water quality, the weather is expected to be the decisive factor in whether the events can proceed. Heavy rain risks worsening water quality and increases the river's flow speed, making it difficult for athletes to compete. June is a rainy month in Paris, but the city stated that it is experiencing drier and sunnier weather than before and that the events could proceed as planned. However, the Associated Press analyzed weather data and pointed out that this year has the second-highest number of rainy days in Paris since 1950.

If the water quality problem is not resolved, swimming events cannot be held in the Seine. The Paris Olympic Organizing Committee has decided that if it is deemed difficult to hold the event in the Seine on the day, the competition will be postponed for several days, and in the worst case, the triathlon will be converted into a duathlon, consisting only of marathon and cycling without swimming. The open water swimming event is planned to be held at another venue where rowing and canoeing events take place.

Experts have evaluated that it is difficult to predict at this point whether the events can proceed as planned. Dan Alhelescu, founder of Fluidion, a water quality monitoring technology company that has studied the Seine's water quality for years, told Euronews that since the newly installed reservoir and other infrastructure in Paris were not operational until a few months ago, it is difficult to predict what will happen at the end of this month based solely on data from the past few years.