Australian Olympic team technical advisor Andrew Lechte recommends not throwing any winning sailors into Rio's waters.
Because they are so polluted and full of floating junk.
Rio de Janeiro's Guanabara Bay, where the sailing and windsurfing contests will take place, is perhaps the world's prettiest garbage dump.
Brown clouds of human excrement gush from two large drains directly into Marina da Gloria, the Olympic sailing headquarters.
That's just a drop in the overall flood of untreated sewage and general junk pouring from a metropolitan area of some 12 million people, into Guanabara Bay as a whole.
"You won't be throwing the winner in," says Lechte, a member of Team Australia's advance party.
A boat ride with Lechte onto the bay revealed water fouled with household waste such as bottles and plastic bags and pretty much anything else.
"I've seen a fridge door, mannequins, whole beds, doors and windows," said Airton, who leads one of the so-called "eco-boats," or floating garbage trucks, that officials have deployed in a last-ditch effort to clean the bay in time for the Summer Games.
"I've seen dead dogs, cats - all animals," he continued. "Even a horse."
When Rio de Janeiro beat Madrid, Chicago and Tokyo in 2009 to host the 2016 Olympics, one of the headline promises in the winning bid was to cut pollution in Guanabara Bay by 80 percent.
Long-term neglect of municipal garbage collection, antiquated sewage systems and a generally cavalier attitude towards the environment have left the bay filthy.
"The main problem is the sewage which drains from practically all the rivers reaching the bay," Mario Moscatelli, a prominent environmental activist and professor of biology at the Federal University of Rio de Janeiro, told AFP.
"Basically, large areas of the 21st century metropolitan area of Rio de Janeiro continue to live with basic sanitation from the 18th century. In other words, all the sewage produced in large areas is reaching the bay without any treatment."
Even officials have generally shown little confidence in their 80 percent goal, with Rio state Governor Luiz Fernando Pezao saying in February: "I don't know what percent we'll achieve."
The International Sailing Federation said on Saturday it would start its own independent testing for viruses in Rio's Olympic waters after tests showed a serious health risk to athletes.
The controversy has turned the relatively minor sport of sailing into the most talked about aspect of Brazil's Olympics preparation, embarrassing a country that wants the Games to demonstrate its rise as a global economic power and regional giant.
Top flight international sailors have condemned the pollution, citing not just potential health hazards but the more immediate risk of floating debris impeding boats and spoiling races that are decided by tiny margins.
A semi-submerged television would probably break or capsize a racing dinghy but even hitting something small could rob precious speed, possibly making the difference between gold and zero.
"You don't even want to hit a plastic bag," Lechte said.
Races usually won by skill at working with the boat and wind, may instead be decided by which sailor is best at spotting the hazards.
"That will make or break the results. Everyone will have to deal with it," Lechte said.