Samples taken from the river showed that E. Coli levels were above the recommended limit at four different sites for nearly the entire week of June 10 to June 16, per Le Monde with AFP.
“Samples from the Seine do not meet the standards we will have this summer,” Paris region official Marc Guillaume added on Friday.
The Seine was poised to be a centerpiece of the Paris Olympics, featuring prominently in both the opening ceremony and various swimming events.
The city of Paris invested $1.5 billion in cleaning the river ahead of the games, with regular testing of bacterial levels to ensure athletes’ safety.
But officials say heavy rainfall has scuppered those plans thus far, leading to high rates of two kinds of fecal bacteria, including E. Coli — which is “the species of coliform bacteria that is the best indicator of fecal pollution,” according to the New York State Department of Health.
“Water quality remains degraded due to… rain, high flow, little sunshine (and) temperatures below seasonal norms,” a weekly report published by the Paris region and mayor’s office said, per Le Monde with AFP.
Paris’ 19th-century sewage system can be overwhelmed by bad weather, leading to urban runoff, which carries pollutants to streams and rivers.
The Seine has been off-limits for swimming since 1923 due to high pollution levels.
Last year, triathletes took part in a test event in the Seine, with some airing concerns about their safety.
Norwegian Olympic gold medallist Kristian Blummenfelt said: “I always dive with open mouth. It’s not going to be funny if I wake up tomorrow morning with … whatever,” per ESPN.
A number of other test events in the river have been canceled due to pollution levels and bad weather.
Nevertheless, Guillaume said he was “confident” that swimming events would go ahead as planned.
“At one point or another, the weather will change, it’s going to stop raining and we’re going to have sunshine … It is in summer conditions that we must be able to examine swimmability,” he said, Axios reported.
The 2024 Olympic Games is set to kick off on July 26.
The overall economic impact of the Olympic Games on the Paris region could range from 6.7 billion euros to 11.1 billion euros, or around $7.1 billion to $11.8 billion, according to a study published by Center for Law and Economics of Sport.
Business Insider contacted the Olympic Games Paris 2024 for comment.