chlorine level

Jump to latest Follow Reply
D

DMS2014

Silver Supporter
LifeTime Supporter
Jun 22, 2014
811
Houston, Texas
The husband was concerned about chlorine levels/cancer. We did some searching and found that safe is 4PPM over a long period of time. Is this accurate? I mean, right now our FC is 12 and he thinks that's too high to swim in. Thoughts, please.
 
Have him read through this thread - it will give him an indepth review of water chemistry, Free Chlorine, CYA, and their interaction.

Pool Water Chemistry

You are safe to swim in FC up to your shock level based on your CYA. The 4 ppm you reference is in ZERO CYA. That is what municipal water systems use. The active CL in your water with CYA is minuscule compared to that.
 
This is a great summary:

JoyfulNoise said:
Free chlorine is a measure of three different chemical species - hypochlorous acid (HOCl), hypochlorite anion (OCl-) and chlorine bound to CYA (chlorinated cyanurate). When you do the DPD-FAS test, the dye reacts with all three components and so you are measuring the sum of all active chlorine species (HOCl/OCl-) as well as the chlorine held in reserve (CYA-Cl).

Chlorine that is bound to CYA is inert - in other words, if there is nothing for it to react with, the chlorine will stay bound to the CYA and it will not do much. Chlorine can be released from CYA as the HOCl/OCl- gets used up in solutions and the reaction rate for chlorine being released is about 0.25 secs. When the FC/CYA ratio is ~7.5% and the pH is ~ 7.5, the active chlorine (HOCl/OCl-) levels in solution are split about evenly and the total concentration of them is 100ppb (0.1ppm). This level of active chlorine is high enough to kill algae and pathogens but low enough to be quite safe. By contrast, water with no CYA in the water, it has ~15X the amount of active chlorine in it than when the FC/CYA ratio is 7.5%.

As for human health effects, they are minimal. There is very little dermal absorption of chlorine through the skin and into the body as you skin is a very effective barrier against the environment. Does the active chlorine react with your skin? Sure. But there is so little of it in solution that it's practically meaningless. The analogy would be a person shooting spitballs at a Sherman tank.

What about ingestion?? Well, first off, no one would suggest drinking pool water. Does some get into your mouth and nose? Yes. But again, the quantities we are talking about are so low that they are insignificant. The human body has plenty of anti-oxidant mechanisms that will neutralize free chlorine inside the body. In fact, one of the kill mechanisms of your immune system is for the immune cells to generate hypochlorous acid in-situ to kill pathogens.

As an aside, hospitals actually use a bleach/water solution for disinfecting difficult to treat wounds that is hundreds of times more concentrated than pool water (YippySkippy can give us the link) and contains no CYA so it is completely unbuffered. Some dermatologists also recommend bleach baths for people with eczema or psoriasis as a way of reducing skin inflammations.

There is simply not enough chlorine in pool water to be at all concerned about human health effects and there is no studies that I am aware of that show any kind of adverse cumulative health effects. I don't have links at hand but considering how much chlorine is used in the treatment of municipal water supplies, I suspect one could easily find thousands of epidemiological studies done by the CDC and EPA regarding the human health effects of chlorine in drinking water.
Click to expand...
 
DMS2014 said:
boy, that's technical!
Click to expand...
As you said earlier, he shouldn't have to accept "TFP said so" as an answer. We offer verified and reproducible data alongside personal experience to back up what we do. I do hope your husband is demanding the same rigorous verification from any source that has him concerned about chlorine causing cancer in the first place.

That is the way chlorine-free pool systems get sold. People don't know better and are easily convinced that chlorine is dangerous. So they end up with pools that aren't sanitized, which allows various organisms to grow that pose infinitely greater risk than the chlorine they are attempting to avoid. The quote Dom posted above from JoyfulNoise sums up my thoughts on the dangers of chlorine though, "practically meaningless."
 
as usual, you guys rock. I trust you guys know what you are talking about and sometimes I need a little help getting the message across Especially when you google it and it's the exact opposite of what it says here <rolling my eyes.>
 

Enjoying this content?

Support TFP with a donation.

Give Support
That article is not only 'much to do about nothing', it is based on indoor pools, where 99% are public pools.

The best advise there is to avoid public pools, keep your head above water and shower immediately following a swim.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply