Key questions answered after triathlon postponement

Swimming has been banned in the River Seine since 1923

The Olympic men's individual triathlon at Paris 2024 was postponed on Tuesday after tests showed that water quality in the River Seine did not meet the acceptable standard.

With organisers now saying there is only a 60% chance that both the rescheduled men's event and women's race could take place on Wednesday, it only adds to the uncertainty around the event.

BBC Sport looks at all the key questions around the triathlon and possible contingency plans.

What would make the Seine safe?

On Tuesday, organisers said E coli bacteria found on four points on the 1,500m course just under 24 hours before the postponement was the main area of concern.

According to European standards, the safe limit for E coli is 900 colony-forming units (cfu) per 100ml. The four readings taken ranged from 980-1,553 cfu per 100ml.

Between 17-23 July, data showed the river that bisects the French capital was suitable for swimming on six days out of seven.

Unexpected adverse weather has proved problematic for organisers since, with heavy rainfall on the day of the opening ceremony raising pollution levels.

UK Government guidelines say that because of micro-organisms like E coli, open-water swimming can increase the risk of stomach bugs as well external infections, and could cause severe illness.

What happens next?

Great Britain's Alex Yee is one of the favourites for gold in the men's race, while team-mate Beth Potter is the reigning women's world champion.

On Tuesday, the postponement of the men's race was announced at 03:00 BST, four hours before the race was due to begin.

Final tests of the water will be taken at 02:30 BST on Wednesday, before a decision is made on whether it is safe for swimming.

The women's race is set to start at 07:00 BST (08:00 local time) on Wednesday, with the rearranged men's competition scheduled to begin at 09:45 (10:45 local time).

To complicate matters further, Meteo-France - the French national weather and climate service - has forecast storms for Tuesday evening, light rain on Wednesday afternoon and more storms on Thursday.

Organisers have said heavy rain previously caused levels of E coli and other bacteria in the Seine to rise.

While there is hope that hot weather will help lower the bacteria count sufficiently for the competition to proceed, that may present another issue as the men's race is scheduled to head towards its conclusion during the hottest part of the day, when the temperature is forecast to reach 32C.

Could triathlons become duathlons?

If the triathlons do not go ahead on Wednesday, Friday remains a back-up date for both events.

If the water quality is still not good enough by Friday, organisers have said the event could be contested as a duathlon - just the cycling and running legs - as a last resort.

The triathlon made its Olympic debut in Sydney in 2000. The event features 1500m of swimming, a 40km bike ride and a 10km run to finish.

While a mixed relay was added in Tokyo three years ago, there has never been a duathlon in the Olympics. Ordinarily that would consist of a 40km cycle and a 10km run.

However, at the Paris Test Event in 2023, a duathlon format was trialled, with the swim replaced by an additional 5km run.

How could this affect the athletes?

While Olympic coaches and athletes are usually prepared for most eventualities, it is unlikely many training plans will have been tailored specifically for a duathlon.

Commenting on World Triathlon's Instagram post announcing the postponement on Tuesday, Belgian triathlete Marten van Riel expressed his dissatisfaction with the situation.

He wrote: "If the priority was the health of the athletes this event would have been moved to another location a long time ago.

"We are just puppets in a puppet show. Duathlon is no triathlon and changing the day like that in the middle of the night is disrespectful to the years of preparation of the athletes and to all (y)our fans that were going to watch live or on TV. What an appearance for triathlon on the biggest scene."

American competitor Seth Rider has been preparing for exposure to bacteria.

"We know that there's going to be some E coli exposure, so I just try to increase my E coli threshold by exposing myself to a bit of E coli in your day-to-day life," he said on Saturday.

"Just little things throughout your day, like not washing your hands after you go to the bathroom and stuff like this."

Should this problem have been seen in advance?

Locating the start of the triathlon at the Seine was considered a historic, albeit remarkable, decision.

Critics may argue it was more about aesthetics, given swimming in the river has been prohibited for over 100 years because of its high levels of pollution and the risk of disease.

However, French authorities have invested 1.4bn euros (£1.2bn) to make the Seine swimmable as a key legacy of the Games.

That work includes the construction of a giant underground basin the size of a dozen Olympic swimming pools to capture excess rainwater and keep wastewater from flowing into the river, renovating sewer infrastructure and upgrading wastewater treatment plants.

Despite that, levels of E coli were 10 times more than the acceptable level imposed by sports federations as recently as June.

France currently lags behind the European Union’s average score for top-quality bathing water conditions.

British triathlete Vicky Holland, who took bronze at the Rio Games in 2016, told BBC Sport: "This is something that is a huge deal, not just in our sport, but for the wider world as well.

"There are less and less bodies of water in the world that are safe to swimmers and that's a real shame. It really highlights that we really need to try and clean up these bodies of water. I know that here with Paris, that is something they tried to do.

"They spent a huge amount of money trying to clear up the Seine and they have done a really good job of it, it just quite hasn't meant the standard yet."