Olympic marathon swimmers test Seine River amid concerns of contamination

The Seine River has brought angst among athletes and officials as contamination concerns have continued through this year's Summer Olympics.

On Wednesday, World Aquatics announced that swimmers were testing the waters ahead of the upcoming marathon swimming events. The marathon swimming events are arguably the most concerning among those being held in the Seine. While the men's and women's Olympic triathlons include a 0.93-mile swim, marathon swimmers will spend a much longer period of time in the water, traversing 6.22 miles.

The women's marathon swimming event will be held on Thursday, with the men scheduled to compete on Friday.

The marathon swimming events will be the fourth and fifth ones to be held using the river. Last week, the men's and women's triathlon events were performed there. And on Monday, the mixed-gender triathlon relay event was allowed to proceed.

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But the men's triathlon event was postponed by a day after high levels of E. coli were detected in the Seine. Subsequent tests revealed E. coli levels returning to normal levels, allowing athletes to continue competition. Tests of the river also prevented marathon swimmers from testing the waters on Tuesday. On Wednesday, officials said bacteria levels in the river returned to normal levels.

Although the men's and women's triathlon events were held, the concerns over river pollution did not die down before the mixed triathlon. Over the weekend, Belgium said it withdrew its mixed triathlon relay team after officials said that Belgian athlete Claire Michel got sick days after the women's triathlon event.

Michel later revealed that tests showed that she was ill due to a virus and not E. coli.

"I am gradually doing better and I returned home to Belgium today," Michel said on Tuesday. "Blood tests showed that I contracted a virus (not E. Coli). After three days of vomiting and diarrhea, which left me quite empty, I ended up needing more significant medical attention and spent the Sunday at the clinic."

Concerns were raised prior to the Olympics about the water quality in the Seine. French officials have long prohibited swimming by the public in the river due to contamination. But there have been government efforts to reduce pollution in the water, which is partly why Olympic athletes were allowed to compete in water events in the Seine.