Organisers were forced on Sunday to cancel the Open Water Swimming World Cup in Paris, after heavy rainfall caused the water quality in the Seine river to dip below minimum health standards.
The river is due to be the venue for marathon swimming at next year's Olympic Games, and global swimming federation World Aquatics said "extra work" was needed to ensure back-up plans were in place for that.
"Disappointed is the right word," French Swimming Federation head Gilles Sezionale said on local radio. "First and foremost disappointed for the athletes, who were dreaming of competing in one of the most beautiful locations in the world."
Participants had been barred from morning training on Friday for the same reason.
Saturday's women's 10 kilometre race - a qualifying event for the Olympics - had originally been postponed to Sunday, when the Federation and World Aquatics cancelled both it and the equivalent men's race.
"It's obvious that extra work is required with Paris 2024 and local authorities to guarantee solid emergency plans are set up for next year," said World Aquatics.
The Olympics committee said in a separate statement that new infrastructure would be up and running by summer 2024, which should ensure better water quality and make the Seine swimmable.
An 80 billion euro ($88 billion) underground overflow basin designed to prevent bacterial contamination of the river by heavy rains is expected to be completed before the games.
TRIATHLON TEST EVENT TO GO AHEAD
World Triathlon said on Sunday that triathletes would still compete on the Olympic and Paralympic courses for the Paris 2024 test event from Aug. 17-20 - with the swimming legs taking place in the Seine.
"For Paris 2024 and World Triathlon, the health and safety of athletes is our top priority," the sport's governing body said in a statement.
"We will therefore... continue to carefully monitor water quality over the coming days, in the confident expectation - based on the current weather forecast - that elite athletes will compete in the Seine later this month.
"In the unlikely event that water quality does not meet the requirement of World Triathlon and public health authorities, a contingency plan is in place which would see the race(s) shifted to a duathlon format."
On Thursday, the Guardian reported that at least 57 participants fell ill after competing in sea swimming events at the World Triathlon Championship Series in Sunderland, England.
