PARIS, FRANCE -- German swimmer Leonie Beck became ill after competing in the women's open water race at the Paris Olympics, despite assurances that the water in the Seine River was safe.

Beck, who finished ninth in the 10-kilometre event, on Saturday posted on Instagram a picture of herself giving a thumbs up but looking ill.

鈥淰omited 9 times yesterday + diarrhea,鈥 she posted, before adding sarcastically, 鈥淲ater quality in the Seine is approved," accompanied by a check mark.

Concerns about the long-polluted Seine, where swimming had been banned for more than a century because of bacteria-laden waters, came to the forefront after Paris organizers announced plans to hold open water swimming and the swimming portions of triathlon in the iconic river that runs through the heart of the French capital.

Despite a massive, expensive cleanup project, some readings showed unacceptable levels of bacteria such as E. coli, leading to changes in the triathlon schedule and cancellation of one of two open water training sessions scheduled ahead of the men's and women's 10-kilometre races.

Several athletes fell ill after the triathlon, but it wasn't clear if any of their conditions were caused by swimming in the Seine.

A total of 53 swimmers 鈥 29 men and 24 women 鈥 competed in the open water races. Most said the cleanliness of the water was not an issue, with women's gold medalist Sharon van Rouwendaal of the Netherlands saying she actually took a few gulps of the river when she was feeling parched during her race.

鈥淚t was cold,鈥 she said. 鈥淚t was nice.鈥

Ireland's Daniel Wiffen, a swimming gold medalist in the 800-metre  freestyle who competed in his first open water race, shrugged off concerns about the cleanliness of the waterway. He said the readings he saw ahead of the men's race showed less E. coli in the Seine than one would normally find in a pool.

The Paris organizing committee issued a statement saying it had 鈥渉eard reports of the athlete鈥檚 illness and we wish them a speedy recovery.鈥

鈥淎t this stage, we are not aware of any established link between the illness and the Seine鈥檚 water quality," the statement said. 鈥漌ater quality on the day of the marathon was considered 鈥榲ery good鈥 or 鈥榚xcellent鈥 across all four testing points and well within the thresholds established by World Aquatics."

World Aquatics did not immediately respond to a request for comment.

Associated Press Writer Angela Charlton in Paris contributed to this report.