Olympic athletes competing in Rio's polluted waters are fearful that performing on the biggest stage of their careers will affect their health.
"[The water quality] is a real concern. We're going to have to be very disciplined about how we're taking care of ourselves," Meghan O'Leary, U.S. Rowing competitor told The Courant.
An eight-month study conducted by the Associated Press concluded that none of Rio's water venues were safe for swimming or boating.
The study found over a billion viruses from human sewage in a single liter of water from the Rodrigo de Freitas Lake. The water measured 1.7 million times the level of what would be considered hazardous on a Southern California beach.
Rio's Olympic bid guaranteed a seven-year project to collect 80 percent of the sewage in the Rodrigo de Freitas Lake before the summer games.
However, just last August, German sailor Erik Heil was treated for a bacterial infection after Olympic test events in the waters.
"I'd never had leg infections before. Never! I can only assume I picked them up at the test regatta," he wrote on the German Sailing Team's Olympic blog.
Heil believes he contracted the infection in the Marina da Gloria, where untreated waste water flows from a Rio hospital.
In the same month, 13 of the 40 rowers on the U.S. Rowing Team suffered from a stomach illness following the World Rowing Junior Championships. The team's doctor suspected the illness was caused by the pollution in the water.
Though the government has developed water purification systems since the bid, the AP reported that ingesting three teaspoons of the lake water Heil and the U.S. rowers competed in would result in a 99 percent chance of infection.
This August, 1,400 rowers, canoers and marathon and triathlon swimmers will risk infection when competing in the dangerous waters.
"It won't take us out of wanting to compete, but there is that level of stress created," O'Leary said. "I put all this time in and something I cannot control might take me off my game."
A new study released this June also found a drug-resistant super bacteria in Rio's competition waters, Reuters reported.
The threat is known to cause deadly infections and meningitis. According to the CDC, the bacteria contributes to death in up to 50 percent of people infected.
"The Olympics are about people performing at their best, bringing countries together and celebrating excellence," U.S. rower Grace Luczak told the Mercury News. "It's tough when you are going to be in an environment when you might not achieve that."
"At this point it's obviously not ideal," U.S. sailor Helena Scutt told The New York Times. "And I'm not the first to say that."
Calls for a venue change by critics like Peter Sowrey, former CEO of World Sailing, have been largely ignored.
"I didn't resign. The board finally told me to leave," he said about being fired as chief executive of World Sailing after voicing concerns.
Contaminated waters are not the only health hazard athletes and coaches are concerned about this year.
"Everyone who competes in these water-based venues- you've got not one serious thing, but two, to consider as you're preparing for wanting to perform at 100 percent," O'Leary said referring to the Zika virus, another major health concern for Rio. "Either one of those will knock you out and be a severe detriment to your performance level."
With the opening ceremonies on the horizon, athletes have tried to make the best of the challenges they will face.
"It's easy for people to say [we] should just throw their hands up and not compete, but the reality is that if we do that, there's 50 people on line behind us who will take our spot," Scutt said.
Scutt said that she is remaining focused on her job in Rio: to win a medal.