P - The Australian sailing team has backed serious concerns voiced by Olympic sailors about animal carcasses and other toxic debris in the water at the 2016 Rio Games venue.
"There's absolutely no doubt that pollution is a major issue in Guanabara Bay," Australian team boss Peter Conde said on Sunday.
"We've seen it ourselves, we've experienced it."
Conde said Australia's Olympic sailing team, which topped the sailing medal table at the London Games, were likely to take health precautions while training and competing off Rio over the next three years.
"We know and the Australian Olympic Committee knows that they're going to have to work very closely with the International Olympic Committee and the Brazilian organising committee to make some major improvements there," he added.
"Otherwise it will be a serious health risk. It's a big challenge."
Danish sailor Allan Norregaard, a bronze medallist at the London Olympics, is among a number competitors to voice the latest concerns.
The 49er skiff sailor said that while sailing off Rio in the last few days he'd seen entire trees floating in the bay, doors, chunks of timber with nails protruding, swollen mattresses and endless plastic bags.
Another sailor talked about a horse carcass in the 148-square-mile bay, which opens into the Atlantic just above Rio's famed Copacabana beach.
Other sailors have previously spoken of seeing dead cats and dogs washed into the sea from the numerous water outlets that run into the bay.
Norregaard said the floating debris makes racing unfair and dangerous.
The other issue is the health risk with high levels of fecal coliform bacteria in the water, and Norregaard spoke of people emerging from the water covered in red dots.
"I've been sailing all over the world for 20 years now, and this is the most polluted place I've ever been," he added.
"It's really a shame because it's a beautiful area and city, but the water is so polluted, so dirty and full of garbage."
Rio's local Olympic organising committee has promised the pollution will be cleaned up when the Olympics open in 2 1/2 years.
Government officials have pledged to reduce 80 per cent of the pollution flowing into the bay.
But some sailors doubt the problem can be fixed after festering for decades, and many worry about their health. Environmentalists call measures being taken "stopgap," likely to mask the problem and not cure it.
"Of course, the water will not be clean as sailing in the Caribbean," Brazilian sailor Robert Scheidt, who has won five Olympic medals, told The AP.
"I have never swum in there (Guanabara). ... Inside the bay I know it's not the proper place to swim. I've sailed there and never got any disease."
Ian Barker, who won a silver medal for Britain in the 2000 Olympics and now coaches Ireland, said he's sailed in 35 countries, and Brazil was the worst.
He said sailors in training have had to stop to disentangle their rudders from rubbish.
"It's a sewer," he said. "It's absolutely disgusting. Something has to be done about it. But you need the political will for these things to happen and at the moment it's not there."
Conde said there were pollution problems at the 2008 Olympic sailing venue at Qingdao, China, with some competitors training near an untreated sewerage outlet.
"But this (Rio) is probably worse than that because it's more widespread," he added.
