Guanabara Bay: the sailing venue for the 2016 Olympic Games | Photo: Rodrigo Moraes/Reuters

The British Sailing Team is concerned about water quality in Guanabara Bay, the sailing venue for the 2016 Olympic Games.

The waters of Rio de Janeiro are heavily polluted. Despite the promises from the local authorities, the amount of untreated waste flowing into the Guanabara Bay will not be cut by 80 percent, as initially announced.

"The sailors are on various supplements to mitigate against it, but we can't do anything about the water quality," Stephen Park, British Sailing Team's manager, told Reuters.

Nick Thompson, one of Britain's top sailors, says, "water quality is my biggest personal concern. If you are sick during the Games, it's game over." That is why he will be "taking probiotic supplements and fish oil to strengthen the gut."

Recently, thousands of dead twaite shad have been found floating in the waters of Guanabara Bay. The eight million residents of the 15 cities that share the bay's shoreline are still contributing to the amount of untreated sewage released.

"We want every single venue to be ready for the athletes to compete in a secure and safe manner. We have been given reassurances that all the venues will meet the level, so athletes can compete," Nawal El Moutawakel, head of the IOC inspection team.