Olympic open water swimmers received the green light on Wednesday to train in the Seine River, a long-polluted stretch now deemed safe by Paris organizers.
A two-hour training session, the only opportunity to get acquainted with the scenic course through central Paris, was scheduled, according to an email from World Aquatics Communication Manager Torin Koos.
It remains uncertain how many swimmers will take advantage of this test run, which precedes the women’s 10-kilometer marathon event scheduled for Thursday, with the men’s race set for Friday.
World Aquatics canceled a test run Tuesday due to concerns over fluctuating bacteria levels in the waterway. Despite massive efforts to clean the Seine, water quality has been a constant concern throughout the games.
Open water swimmers typically train in the controlled environment of a pool. Given concerns about bacteria levels in the Seine, many may opt to skip the training session and limit their time in the river to the actual event.
However, some might want to familiarize themselves with the conditions, especially the strong current that has also raised concerns among the athletes.
Triathlon events have already been held in the river, though the schedule was disrupted by daily water quality readings.
The open-water swims have a backup plan in place if the Seine is deemed unsafe. The races would be moved to Vaires-sur-Marne Nautical Stadium, the site of the rowing and canoeing events.
The triathlon mixed relay event took place on Monday. World Triathlon released data Tuesday showing that levels of fecal bacteria E. coli and enterococci were within acceptable limits during the triathlon relay course swims.
The marathon swims will cover longer portions of the river, starting and finishing at the Pont Alexandre III. Marathon swimmers will complete six laps on the 1.67-kilometer (1-mile) course, totaling 10 kilometers.
Organizers said they "remain confident” that the marathon swimming events will occur in the Seine as planned, based on "a favorable weather forecast and forward-looking analysis.”
Paris Mayor Anne Hidalgo, who took a highly publicized swim in the Seine in July to address water quality concerns ahead of the Olympics, echoed that confidence.
"There’s been a clear improvement in the weather these past few days,” she said. "So I’m really proud and happy, and to those who continue to say it’s impossible to clean a river, I tell them, 'Yes, it’s possible; we did it.’”
With a few exceptions, swimming in the Seine has been prohibited since 1923 due to the water's toxicity.
Paris undertook an ambitious plan, including 1.4 billion euros ($1.5 billion) in infrastructure improvements to ensure that some swimming events could be held in the river. This included constructing a giant basin to capture excess rainwater and prevent wastewater from flowing into the river, renovating sewer infrastructure and upgrading wastewater treatment plants.
Water quality in the Seine is closely linked to the weather. Heavy rains can cause wastewater and runoff to flow into the river, leading to elevated bacteria levels, while warm temperatures and ultraviolet rays can kill germs and lower those levels.
Although the weather has mostly been hot and sunny during the Games, there have been several instances of heavy rain.
Four triathletes – out of more than 100 who competed in the men’s and women’s individual races last week – became ill in the following days, though it’s unclear whether the water was the cause.
Most strains of E. coli and enterococci are harmless, and some reside in the intestines of healthy people and animals. However, others are dangerous, and even a mouthful of contaminated water can cause infections in the urinary tract or intestines.
