Paris 2024 Olympic Games: “Water quality remains degraded”, a little over a month before the Games, the Seine is still too polluted

Will the tests be fought ? MAXPPP – MICHEL CLEMENTZ

The Seine was too polluted on June 16, a month and a half before the Olympic Games (July 26 – August 11), with regard to the criteria for authorizing triathlon and open water swimming events, according to the results of ;analyses published Friday.

"To date, the samples in the Seine do not correspond to the standards that we will have this summer", a commented during a press point by the regional prefect Marc Guillaume, who said "confident, with the Cojo (Organizing Committee), that the events will be held at the end of July and beginning of August in the Seine".

According to the weekly bulletin published by the Paris town hall and the Île-de-France prefecture, the bad weather in France in recent days explains concentrations well above the standards of the two fecal bacteria to authorize competitions in the river.

"Water quality remains degraded due to an unfavorable hydrological and meteorological context: rain, high flow, low sunshine , temperatures below seasonal standards", explain local authorities.

Above threshold

“The high flow of the river, which does not promote good water quality, is the result of this very rainy weather”, they also recall. According to the graphs posted online, the concentration level of fecal bacteria E.Coli was higher than 1,000 colony-forming units (CFU)/100 ml, the threshold retained by the international triathlon and open water swimming federations to authorize the holding of events, almost every day from June 10 to 16. It even reached or exceeded 5,000 units on June 11, 15 and 16.

A postponement as plan B

A rise that "is'explained by upstream discharges linked to rain", according to the city hall and the prefecture. The star of these Olympic Games, the Seine will host the opening ceremony as well as the triathlon, swimming-marathon and paratriathlon events. But the suspense remains over the holding of the Olympic events since the "test-events" August 2023, which had to be largely cancelled due to poor water quality.

In the event of heavy rainfall, untreated water – a mixture of rain and wastewater – can be discharged into the river, a phenomenon that retention structures inaugurated just before the Games are intended to prevent. Plan B is to postpone the events by a few days, but not to change the venue.