Paris: The River Seine failed its first Olympic test on Saturday as a training session for triathletes was scrapped after the water failed pollution checks. A statement from Paris 2024 organisers and World Triathlon said "a joint decision was taken to cancel the swim leg of the triathlon familiarisation" but that running and bike training sessions would "go ahead as planned." The quality of the Seine -- which is set to be used for triathlon and marathon swimming -- is dependent on the amount of rain that falls in and around Paris.

Heavy downpours of the sort seen on Friday during the sodden opening ceremony of the Games overwhelm the city's sewage system, leading to discharges of untreated effluent into the waterway. "We're not particularly worried," chief organiser Tony Estanguet told reporters during a trip to an equestrian event at the Versailles Palace on Sunday. "We're vigilant as we have been since the beginning.

" "We know that for 24 to 48 hours after heavy rain that we might need to delay (events)," he added. "The weather forecast shows that in theory the rain shouldn't return." The triathlons are set to take place on July 30-31 and August 5, followed by the open-water swimming on August 8-9.

Due to an exceptionally wet spring and start to summer, the Seine had been consistently failing water tests until the start of July. Levels of the E.Coli bacteria -- an indicator of faecal matter -- were sometimes 10 times higher than authorised limits.

"Paris 2024 and World Tria.