Athletes swim in the Seine river for the triathlon event at the Olympic Games in Paris on Wednesday, July 31.
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Athletes swim in the Seine river for the triathlon event at the Olympic Games in Paris on Wednesday, July 31. / AFP via Getty Images

Belgium's Olympic team forfeited from Monday's mixed competition triathlon after one of its triathletes, Claire Michel, became sick after swimming in the Seine last Wednesday — a river that's faced frequent water quality and safety concerns.

"The Belgian Hammers will not start in the Mixed Relay competition at the Paris Games," the Belgian team said in a release. "Michel, one of the athletes in the mixed relay team, unfortunately has to withdraw from the competition due to illness."

While the Olympic team did not describe Michel's illness nor blame the Seine, Belgium newspaper De Standaard reported that the triathlete was hospitalized and treated for an E. coli infection Sunday. The bacteria can cause serious intestinal and medical issues.

Meanwhile on Sunday, Olympic organizers canceled a planned practice swim for triathletes after poor water quality test results. In a release obtained by NPR, organizers said "heavy rains" on Wednesday and Thursday led to the practice-swim cancellation. Heavy rains can overwhelm the city’s antiquated sewer system, leaking untreated sewage into the Seine river — increasing rates of E. coli bacteria.

In the years leading up to the Paris Olympic games, France spent more than $1 billion to clean the Seine river, which had been illegal to swim in for more than a century. It has long been considered too contaminated for human use. On July 17, Paris Mayor Anne Hidalgo jumped into its murky waters and declared, "we did it!"

Olympic triathletes — including Michel — last competed in the Seine on Wednesday. As it stands, Olympians are set to swim in the Seine on Monday for the mixed competition triathlon, without the Belgian team. Daily river testing will continue ahead of the Monday triathlon and the marathon swimming races scheduled for Thursday and Friday.

"Belgian Triathlon hope that lessons will be learned for future triathlon competitions," the Belgian team release said. "We are thinking of training days that can be guaranteed, competition days and formats that are clear in advance and circumstances that do not cause uncertainty among athletes, entourage and fans."