Uncertainty over Olympic triathlon after Seine pollution cancels swim practice again

The Olympic men’s triathlon race on Tuesday has been plunged into uncertainty after pollution in the River Seine forced the cancellation of the second and final swimming practice session. Paris 2024 and World Triathlon confirmed that a 4am test had shown the water quality was still below an acceptable standard after heavy rain on Friday and Saturday. There will be a final test at 3.30am on Tuesday, four and a half hours before the race is due to begin.

“Paris 2024 and World Triathlon reiterate that the priority is the health of the athletes,” the organisers said. “The tests carried out in the Seine revealed water quality levels that in the view of the international federation, World Triathlon, did not provide sufficient guarantees to allow the event to be held. This is due to rain that has fallen on Paris on 26 and 27 July.”

Should the quality not reach the required standard – with E coli levels required to be below the safe limit of 900 colony-forming units per 100 millilitres determined by European rules – there are two contingency days on 1 and 2 August. If the water quality continues to be poor, the men’s and women’s races will switch to a duathlon.

However, organisers remain optimistic backup plans will not be required. “Given the weather forecast for the next 36 hours, Paris 2024 and World Triathlon are confident that water quality will return to below limits before the start of the triathlon competitions on 30 July,” it said. “As observed in July, with summer conditions (more sunshine, higher temperatures, prolonged absence of rain) water quality in the Seine has improved significantly.”

Swimming in the Seine has been banned for more than a century. But since 2015, organisers have spent around £1bn to ensure a cleaner river for the Games and to allow Parisians to swim in it afterwards. Measures taken to improve the water quality have included the construction of a giant basin to capture excess rainwater and stop too much sewage from flowing into the river, renovating infrastructure and upgrading wastewater treatment plants.

The high levels of rain have led to higher levels of E coli than expected and on 17 July the Paris mayor, Anne Hidalgo, took a highly publicised dip in the river in an effort to ease fears over pollution.