The safety of the Seine River remains murky

With the opening ceremony of the Paris Olympics fast approaching, questions remain over whether the Seine will be clean enough for athletes to swim in. Triathlon and marathon events are set to take place in the river, where swimming has been illegal for over a century.

After numerous delays, the mayor of Paris, Anne Hidalgo, finally took a plunge into the Seine this week; she claims the city successfully cleaned it up, "fulfilling a promise that has become a symbol of the Paris Olympics," said The New York Times. Hidalgo postponed her initial plan to swim on June 23 because of the river's water level and the amount of bacteria present. "The Seine is exquisite," Hidalgo said . "The water is very, very good. A little cool, but not so bad.''

Despite this apparent vote of confidence, uncertainty about the safety of the Seine has become a focal point of this year's Games.

'A complicated and very costly problem'

Paris has invested $1.5 billion over the past few years in a massive clean-up project, building new infrastructure to trap more stormwater when it rains. This is the "same water that contains bacteria-laden wastewater that enters the river during periods of heavy rain and makes it unsafe to swim in," said The Associated Press . In May, Paris officials instituted a massive underground water storage basin near the Austerlitz train station to collect excess rainwater and prevent wastewater from flowing into the Seine . The basin holds the "equivalent of 20 Olympic swimming pools." This is the "centerpiece of major infrastructure improvements that the city has rushed to finish in time for the Games," said The AP, but it was also done to "ensure that Parisians have a cleaner Seine in years to come."

While the city has worked hard to clean the river, a few days of torrential rain could push the levels of E. coli beyond the limit of 900 colony-forming units per 100 milliliters, which the World Triathlon Federation has determined as safe for competition."The Seine is not a special case," Metin Duran, a professor of civil and environmental engineering at Villanova University who has researched stormwater management, said to The AP. "It really is a complicated and very costly problem."

Official city testing showed that E. coli levels at The Pont Alexandre III bridge, where the triathlon events will be held, were above acceptable levels on 22 out of 30 days between June 3 and July 2, "potentially exposing athletes to serious health risks," CNN said. Still, authorities say the Seine's water quality has improved recently, and they are "confident for the Olympics now."

"We are having weather that is more consistent with the season," Antoine Guillou, the deputy mayor of Paris, said to CNN. "The quality of the Seine is good."

'The health of the athletes must come first'

Only time will tell if the confidence of French leaders will convince Olympic athletes that the river is safe. Their response thus far has been mixed. "The Seine is not made for swimming," Brazil's Ana Marcela Cunha said to Bloomberg earlier this year. "We know what the Pont Alexandre III and the Eiffel Tower represent, but I think that the health of the athletes must come first." Team USA swimmer Katie Grimes was similarly apprehensive when asked if she was concerned about the quality of the water. "We were supposed to have an Olympic test event there last summer, and that got canceled," she said. By contrast, U.S. triathlete Morgan Pearson said he is "not concerned at all" to Yahoo Sports . With the safety of the water out of his control, he can "only really control myself and my training," he said. "It's honestly not worth even thinking about."

Organizers have several contingency plans if heavy rains affect the Seine's flow during the Games. The triathlon competition would no longer feature the swimming leg, and marathon swimming would be moved to the Vaires-sur-Marne Nautical Stadium in the greater Paris region. Canceling the swim portion is uncommon, but it "has happened a few times," Olalla Cernuda, the head of communications at World Triathlon, said to The AP. "And it's always linked with water quality issues."