PARIS — To the Paris Olympicsbe the the quality of the water in the river Seine is quite safe to host some swimming events has been a major question.
Bacteria levels in the river they float constantly, and daily water samples are tested so that organizers can assess the risk and determine whether to go swimming in the long polluted Paris waterway.
Triathletes ran in the river Mercury, and the organizers said on Sunday evening that Monday’s mixed triathlon event will be held as planned with the swimming part in the Seine. Testing will continue ahead of the marathon swim races scheduled for Thursday and Friday.
Here are some things to know about water quality tests in the Seine:
High levels of E. coli and enterococci indicate wood or faecal water pollution in the water. Most strains are harmless and some live in the intestines of healthy people and animals. But others can be dangerous.
Even a mouthful of contaminated water can lead to diarrhea, and diseases such as infections in the urinary tract or intestines can result.
How susceptible a person is to falling ill from exposure to E. coli depends on many factors, chief among them a person’s age and general health.
“In general, the healthier you are, the more likely you are to resist any kind of pathogen,” said Brian Rahm, an expert in biological and environmental engineering at Cornell University.
Sometimes it’s not even the E. coli itself is cause for concern, Rahm said. “When we see E. coli in the water, it indicates that other types of pathogens and other bacteria, viruses can also be in the water.”
The test helps organizers assess the risk to athletes, but it’s difficult to quantify the exact risk using this data, said Metin Duran, a professor of civil and environmental engineering at Villanova University.
“Unfortunately, there’s not much you can do before exposure to reduce the risk,” Duran said.
Swiss officials said on Saturday that triathlete Adrien Briffod, who competed in the Seine three days earlier, he got sick with a stomach infection. But they said it was “impossible to say” if it was related to their swimming in the river and that other delegations told them that none of their triathletes had stomach problems.
The quality of the water in the Seine is closely related to the climate. Heavy rains cause sewage and runoff to flow into the river, causing bacteria levels to rise, while the sun’s ultraviolet rays can kill bacteria.
And Paris has seen many rain during the Games so far.
To address these contingencies, Paris made 1.4 billion euros ($1.5 billion) in infrastructure improvements ahead of the Olympics, including built a giant basin to capture excess rainwater and prevent runoff from entering the river, renovate the sewer infrastructure and upgrade water treatment plants.
Paris Deputy Mayor Pierre Rabadan said these improvements have made a big difference.
“We never keep rain events from having an impact on water quality. It’s not possible,” he said. “What we have done will allow us to return to a water quality that is satisfactory and good, as it was for the triathlon.”
Organizers they canceled several swimming tests this weekend and last week meant letting the triathletes familiarize themselves with the course on water quality issues after the rain. The men’s triathlon was postponed by a day, then went ahead on Wednesday, the same day as the women’s race.
Decisions about canceling an event are usually made in the early hours of the morning on race day, but organizers on Sunday evening announced their decision to move forward with the race on Monday to give athletes more time to prepare.
Rabadan said infrastructure improvements would prevent wastewater from flowing into the Seine. It was raining Wednesday as the triathletes competed. Wastewater entering the river upstream would take several hours to reach Paris, meaning water quality levels were still safe at the time of that run, he said.
Since then, there has been heavy rain on Thursday night and it will continue to rain on Saturday night.
The organizers said that they consider samples taken from the river 21 and a half hours earlier to allow the cultures to develop in a laboratory.
Daily water quality tests measure levels of fecal bacteria, including E. coli. World Triathlon water safety lines and a 2006 directive of the European Union assign qualitative values to a variety of levels of E. coli.
Under World Triathlon guidelines, E. coli levels of up to 1,000 colony forming units per 100 milliliters can be considered “good” and can allow competitions to go ahead.
World Triathlon in an email called the European Union’s 2006 directive “the most comprehensive guide to bathing water,” based on the range of factors it takes into account. Other organizations, including the US Environmental Protection Agency, set a limit of 126 units per 100 milliliters of water and say higher levels are not suitable for recreational use.
To decide if the events can be held in the river, the medical committee of the World Triathlon said that it will consider the analysis of the water quality, the health inspection and the weather forecast.
A day after Wednesday’s competitions in the Seine, the data published by the World Triathlon showed that a sample taken at 6 pm on Wednesday at the Pont Alexandre III, the bridge where the swimming segment begins and ends , showed a level of 249 units. Samples from other points along the course were at similar levels.
Dan Angelescu, founder and CEO of Fluidion, a Paris and Los Angeles-based water monitoring technology company, says the tests have “flaws” and “severely underestimate bacteria.”
Fluidion tests the water several times a day, and Angelescu said: “What we see is that the water quality is not as good as those measurement data that the city publishes,” resulting in “a underestimation of actual risk”.
The company measures both “free floating” bacteria in the water and takes a “comprehensive” level that Angelescu says also includes bacteria attached to fecal particles or sediment. He said the full count provides a more complete picture than the lab test the city uses.
He compared it to looking at a busy street with pedestrians, motorcycles, cars and buses and trying to count all the people. The city’s method, he said, is similar to counting from a helicopter and weighing each person or vehicle equally because you cannot see how many people are in each car or bus. He says his comprehensive test is more like a police officer stopping every vehicle and counting every person in the cars and buses to get a complete count.
Angelescu said that he discussed these discrepancies with city officials and that they decided to continue with the standard laboratory method that they had used, which complies with the regulations. It was a “fair decision in light of the regulations,” he said. “The problem is that the regulations are wrong.”
Rahm of Cornell University said that ultimately, “from a public health perspective. it doesn’t matter if it’s free flowing or trapped in a soil particle. It gets into your body one way or another other
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Naishadham reported from Washington. AP reporters Jeffrey Schaeffer in Alfortville, France, and Angela Charlton, John Leicester and Ahmed Hatem in Paris contributed.
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