Seine water pollution levels well above limits one month before Games

Paris 2024 Olympics - Paris, France - June 23, 2024 The Eiffel Tower is seen from the water of the Seine River as the Olympics opening ceremony rehearsal is postponed amid rainy weather. REUTERS/Pawel Kopczynski

Water pollution levels in Paris' River Seine remain much higher than allowed for bathing, data showed on Friday, one month before the Olympics in which the capital's landmark waterway is meant to be one of the swimming venues.

Data published on the city's website showed concentrations of enterococci and E.coli bacteria remained well above legal thresholds as of Sunday at all four testing points along the river.

At the Alexandre III bridge, the planned triathlon swimming site, enterococci exceeded a concentration of 1000 colony-forming units (cfu)/100 ml on Sunday, more than double the 400 cfu/100ml limit set by European law. The E.coli concentration was almost four times higher than permitted.

Water pollution levels spike in periods of heavy rain, which in recent weeks have also increased the flow of the river to around six times its seasonal average, Paris's mayoral service said on the website.

"We had a period of historic rainfall in May and a lot of rainfall in June. But that didn't worry us, because we knew that with a significant improvement in weather conditions, we'd get back to summer-like levels," Pierre Rabadan, the city's deputy mayor for sports, told Reuters on Friday.

"The problem is that the most experienced meteorologists, and (in particular) our monitoring manager, are very cautious in their statements."

Rabadan insisted that the only cause for concern would be "repeated and prolonged rainfall", although he hinted the results Paris would publish next week could be much better.

"The conditions are absolutely unusual for the period, but the results are clearly improving," he said.

The French capital has been working on cleaning up the Seine so people can swim in it again, as was the case during the 1900 Paris Olympics. But a sewer problem last summer led to the cancellation of a pre-Olympics swimming event.

Paris mayor Anne Hidalgo, who championed a campaign to clean up the once famously dirty river in time for the Olympics, postponed her planned dip in the river earlier this month, saying it would happen once France's snap elections were over.