Aquatics and Commercial

What caused the green water at the Rio Olympic pools?

November 13, 2016
Image credit: Fernando Frazao, Wikimedia
The green Rio diving pool. Image credit: Fernando Frazao, Wikimedia
Following the embarrassment of smelly green pools at the Rio de Janeiro Olympic Games, Alan Lewis investigated the probable causes.


Competitors in the Olympic water polo pool at Rio de Janeiro  were crying from stinging water and complaining of “fart smells”. It is clear the water had not been maintained correctly, and there is little doubt that the Olympic organisers should be seeking the best advice they can get.

Transparency of the water is dependent on the transparency of the maintenance staff, and the speed of the correction is totally dependent on understanding the science of swimming pool water chemistry.

The first lesson they can learn from this is that they should employ aquatic service people who are certified, with successful careers in managing swimming pools. Above all, it is vital that these “experts” are familiar with swimming pool chemistry in every aspect.

Into the deep end

Diving pools are by necessity very deep. Often the circulation is not homogenous and can be plagued by plenty of “dead areas”.

Outdoor pools are susceptible to the weather and outdoor diving pools are notoriously more difficult to manage than indoor pools. To add to these difficulties, algae spores are easily carried by the wind, which means algae spores inevitably end up in most uncovered outdoor bodies of water. Rain also helps precipitate the spores. Knowing that algae spores are nearly always present in outdoor pools, it is imperative that pool maintenance personnel be familiar with the different varieties (green, black, yellow etc) and know how to deal with them.

Good pool chemical companies are quick to advise and offer algaecides for each individual species of spores – making it reasonably easy to learn the specific solutions on offer. During the pool crisis in Rio, many unbelievable hypotheses were twittered all over the world as an embarrassed Mario Andrada called in an independent service to test the water and assured divers and polo players that, even though the water was a murky, stinky green, it would not affect the health of swimmers!

This was an unbelievable supposition, totally illogical and born out of desperation.

Eventually, after excruciating emotional pressures had run wild, a misguided service admitted that they had slug-dosed 80 litres of hydrogen peroxide (concentration unknown) in each of the pools. What happened then only baffled the staff even further. The water became a darker green, smelly and burned the eyes of the water polo swimmers. Meanwhile, the Chinese divers performed fearlessly and proved their prowess impervious to the unsavoury conditions.

What was happening?

This is an extract from the article by Alan Lewis that appeared in edition 108.

Continue reading the article by viewing the digital magazine.



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