THURSDAY UPDATE: It’s 07h35 in Rio and they’re saying things should be resolved soon, but apparently the swimming pool next to the diving pool is taking on a green cast now as well…if they knew it was about chemicals, shouldn’t they have been on top of it for that one?
NEW UPDATE: Now, they’re claiming it’s a drop in alkalinity due to the treatment system running out of chemicals..hmmm…that still doesn’t explain the cloudiness, I don’t think. Here’s my story in Chemistry World on this, I will attempt to keep abreast (no pun intended) of matters.
UPDATE: It was algae. They just made an announcement. Vindicated. I can’t believe it’s taken them this long. We saw this happen with our lido several times over the years…
There’s a lot of debate about how and why the diving pool at the Rio 2016 Olympic Games has turned from a lovely, crystal clear blue to a cloudy, murky, uninviting pea/pee green. It’s definitely not an additive they put in to show whether anyone was urinating and it’s definitely not Tom Daley’s moisturiser that’s to blame.
People are pointing to the fact that the diving pool has turned but not the adjacent swimming and events pool which remains lovely and clear. Perhaps it’s the smaller volume of water in the diving pool that and the fact it might be held at a higher temperature for comfort. Maybe it also gets more sunlight on it than the other pool? It may well be that the staff looking after the bigger pool were quicker to up the “chlorine” in response to what they saw happening with the diving pool but were too late with latter. The filters may have been contaminated in one and acting as reservoirs of spores, the violent aquatic activity of diving disturbed spores significantly and triggered the bloom.
It’s very hard to get on top of an algal bloom and clear the waters again and admitting that’s what the problem is would probably mean the pool would have to be closed and properly rebalanced and filters cleaned and that might delay subsequent events. Either way, it’s rather embarrassing for the organisers and rather offputting for the divers. That said, I read that one diver said having a more solid colour to dive into is easier in terms of perspective and depth, although I suspect that was PR puff rather than an actual desire.
The main problem in terms of safety for swimming pools that suffer a green algal bloom aside from the toxicity is that lifeguards can no longer see swimmers under water and so there’s a serious risk of drowning if someone sinks or has problems while submerged. Of course, most accidents at pools involve people running and slipping while out of the water or just heart attacks poolside.
There is another theory that they overshocked the diving pool with “chlorine” and this reacts with copper and iron in the water to generate the colour, that would, apparently fit better the timescale of the change and explain why the swimming pool is unaffected. But, that leaves the cloudiness unexplained, not sure whether insoluble copper and iron oxides would form colloidal particles. Moreover, I’ve seen a clear pool go from “colourless/clear blue” to green in a couple of days in a much cooler, less humid UK. So who knows…the Olympic pool people will know…surely?