An Associated Press investigation published results this week that found the Rodrigo de Freitas Lake, an Olympic site thought to have been largely cleaned up in recent years, is among the games' most polluted waters. Results ranged from 14 million adenoviruses (common causes of respiratory illness, cold-like symptoms, sore throat, bronchitis, pneumonia, diarrhoea, and pink eye) per litre to 1.7 billion per litre.
By comparison, water quality experts who monitor beaches in Southern California become alarmed by viral counts spiking to 1000 per litre.
The lake sits in the heart of Rio, a glimmering pool under the towering Christ the Redeemer statue.
Despite the environment's picturesque setting, the towering hills provide an unfortunate disposition for the nearby lake.
"It's pretty small as far as a lake goes and there's 80 million people in Rio. Runoff from the road, overflow from the greywater, unfortunately it goes to the lowest part of the hills," Pehi said of his observations.
Pehi and the strong contingent of New Zealand (a large portion from Parihaka Waka Ama) paddlers didn't fall crook.
Though "some people did get sick", Pehi said there was uncertainty surrounding whether "it was related to the lake".
"We tried to keep out of the water as much as we could but we'd get splashed and stuff like that. We had that alcohol hand cleaner. We had it in our bags so that every time we got off we'd clean our hands before we ate anything or contaminated anything else. We were pretty aware of what the chances of contaminating food and stuff was so we [took] precautions."
More than 10,000 athletes from more than 200 countries are expected to compete in the August 5-21 Olympic Games.
Nearly 1400 of them will come into contact with waters contaminated by rampant sewage pollution, as they sail in the Guanabara Bay; swim off Copacabana Beach; and canoe and row on the brackish waters of the Rodrigo de Freitas Lake. And starting next week, hundreds of athletes will take to the waters in Olympic trial events.
Brazilian officials insist the waters will be safe, but Pehi and the team from Parihaka Waka Ama say: "It's pretty polluted."
