Belgium’s Evi Van Acker is feeling the effects of Rio’s polluted water. (William West/AFP/Getty Images)

Belgian sailor Evi Van Acker, a bronze medalist in the laser radial competition at the 2012 London Olympics, fell ill Wednesday after competing in this year’s event at the Rio Games, and her coach maintains it’s because of the sewage-choked waters of Guanabara Bay, where this year’s sailing events take place.

In fact, Van Acker has been sick since July, when she arrived in Rio for training races on the bay.

“Evi caught a bacteria in early July that causes dysentery,” Coach Wil Van Bladel told Belgian TV network VRT, per the Associated Press. “Doctors say this can seriously disrupt energy levels for three months. It became clear yesterday that she lacked energy during tough conditions. She could not use full force for a top condition. … The likelihood that she caught it here during contact with the water is very big.”

Van Acker’s next scheduled laser radial heat is Friday at around noon EDT. Described by the AP as a favorite to return to the medal stand, she currently sits in 10th place with four preliminary heats remaining before Monday’s medal race. The Belgian Olympic Committee said in a statement that physiologists are working with Van Acker ahead of Friday’s race “so she can get the most out of her energy reserves.”

Laser radial sailing involves one-person boats. As you can see from this video, the sailors often dangle precariously over the edge of their boats, in close proximity to the water:

The AP has been monitoring virus and bacteria levels in Guanabara Bay for some time now, finding dangerously high levels of both because of the human sewage that more or less is poured directly into the water. Before the Games began, a biologist who reviewed the AP’s data advised anyone traveling to Rio to not “put your head under water,” a challenging proposition for Olympic athletes in open-water competitions. Olympic officials have maintained that the bay is safe, even though a number of other competitors were sickened during sailing test events last year.

Denmark’s Allan Norregaard, a longtime critic of the IOC’s decision to hold the races on such a polluted body of water, had no comment on Van Acker’s illness but instead blasted the weather conditions, calling them “just not suitable for the games. … It’s scandalous.”