Algae? Chemicals? Rio's Green Pools Raise Red Flags

The Rio Olympics have taken challenges familiar to water-treatment professionals and thrust them onto the global stage. Sewage discharge into waterways has been a central issue for months. Another problem arose once the games began: chemical imbalances in pool water.

Olympic officials say chemical settings are the reason two pools suddenly turned green during the games. The problem affected a diving pool as well as one used for water polo and synchronized swimming, The New York Times reported.

At first, officials said algae was to blame, but they later revised their statements. Rio spokesman Mario Andrada originally said a “proliferation of algae” caused the problem, according to the Associated Press. “Strangely, the IOC is now walking back the algae explanation and is saying that a chemical imbalance occurred due to too many people using the pool,” Gizmodo reported.

Officials seem to have settled on chemicals as the explanation for the strange color.

“Midafternoon, there was a sudden decrease in the alkalinity in the diving pool, and that’s the main reason the color changed,” Andrada said, per the Times. “We probably failed to note that with more athletes, the water could be affected.”

FINA, the governing body for swimming, also put the blame on chemicals, and provided more details about the color change, per a statement:

FINA can confirm that the reason for the unusual water color observed during the Rio 2016 diving competitions is that the water tanks ran out some of the chemicals used in the water treatment process. As a result the pH level of the water was outside the usual range, causing the discoloration. The FINA Sport Medicine Committee conducted tests on the water quality and concluded that there was no risk to the health and safety of the athletes, and no reason for the competition to be affected.

Some athletes have provided positive feedback about water quality in Rio despite widespread concern about sewage contamination ahead of the games.

“Coming into these Games, the dominant story line for the boating and open-water swimming events wasn’t about the quality of the competition but rather the quality of the polluted water. Some predicted that athletes racing through raw sewage were more likely to wind up in a hospital than a medal stand, while others would have to negotiate sofas submerged beneath the waves. Those fears have gone unrealized,” the Los Angeles Times reported.

Glenn Merry, CEO of USRowing, weighed in: “We prepared for this as we would prepare for any other competition,” he said. “Given how things have played out, we haven’t had any problems.”

To read more about Rio’s water quality problems visit Water Online’s Source Water Contamination Solutions Center.