Call me Melanoma (not to joke too much, but my screen name is LUMP)!
Has anyone else seen this information? I have been swimming regularly in chlorinated pools my whole life. Frankly, this really scares me. Can anyone make me feel better about this? I don't plan to stop swimming any time soon. Your thoughts?
Call me Melanoma (not to joke too much, but my screen name is LUMP)!
The salient point of the article:
"People should not be afraid of swimming, but we should get more research on whether there are better practices for disinfecting pools," said Manolis Kogevinas, an epidemiologist at the Center for Research in Environmental Epidemiology in Barcelona.
Of course chlorine is toxic. Of course, that toxicity leads to some increase in risk.
The question is "How big is that increased risk compared with the dramatic health benefits of exercise?" I'm guessing that it is rather small.
The article itself doesn't measure long term healthy risks - it measures chemical properties of the water, and the skin of swimmers, which could lead to risk.
The risk is hypothetical.
If those risks were real and large, there would be studies that show "Swimmers have X amount of risk for Y condition compared with non-swimmers." You haven't seen those studies. If there is such a risk, it is pretty small.
Now, are there better water disinfectants than chlorine? I hope so. I don't like that stuff.
BS Chemistry, MS Public Health Statistics
No, it isn't bunk, it isn't even all that controversial. EHP is a perfectly fine scientific journal; I'll look up the articles when I have some more time to see what exactly is new in the studies referenced, but any search for "chlorination disinfection byproducts" will come up with many hits.
I only had time to skim the DiscoveryNews article. The idea that chlorination can cause respiratory problems, especially in sensitive people, shouldn't shock anybody who has spent time at pools. Especially in poorly-ventillated pool areas: because of this, the pools I swim in have gone to a non-chlorinated system (uv for one pool, ozone for the other) specifically because the kids were having such a hard time breathing -- excessive coughing, etc -- when the pools were chlorinated. The problems are gone now.
As far as cancer, the risk needs to be put in perspective compared to other sources (eg, smog, second-hand smoke, natural carcinogens, indoor air pollution). The increased risk may be negligible.
But the risks associated with NOT disinfecting the pool, or doing so poorly, are much higher. And swimming is certainly better than being sedentary; all the article is saying is that if you have a choice of pools, go with the one where breathing seems easier. I love my non-chlorine pools (my eyes never hurt when I do my backstroke sets sans goggles) and do wish there were more of them.
Last edited by Chris Stevenson; September 14th, 2010 at 05:50 AM.
I'd love to see more attention to making disinfecting pools with less toxic methods made more available and more cost effective. It is the end of the outdoor season, and indoor swimming is hard on my breathing. I'm sure we have some scientists here and I hope they can get to work on this issue.
Anything that has chlorine in it will be a possible carcinogen. Drinking water standards are now in effect to limit Disinfection by-products (because of chlorine exposure) because they are known to be carcinogens. Same thing can happen in chlorinated pools.
It is also hard for me to believe that those pools only use uv and ozone as a disinfectant because neither one has any residual effects. That is one of the main reasons for using chlorine so it always stays clean, not just at contact.
i've been disappointed at how issues relating health and chemical exposure have been easily dismissed by many on this forum.
i would like to see organizations such as usa swimming, fina, and usms take a proactive approach to create better standards for aquatic facilities to follow for their members. it seems like a far more important issue than (dare i say?) tech suits.
Okay - back on topic.
I agree with Chris and his thoughts on the comparisons between swimming in chlorinated pools and other more common carcinogens. I mean - think about it this way: How long have we been swimming in chlorinated pools over the years? 50-60+ years at least? Even today we have the opportunity to be using better chemicals, better facilities, and more advanced monitoring technologies. This being said - people cut corners. You know it, I know it.
I personally am not terribly concerned. From the linked Discovery article:
Also from the linked Discovery article:The studies were small, and they found a rise in blood markers that have been associated with cancer -- not a rise in cancer itself.
So take from it what you will. However I'm going to worry about the fact that every time I have to be outside in the summer I need about a 30 gallon covering of DEET before the disease infested mosquitoes that I'm allergic to will finally leave me alone far more so than I'm going to worry about being in a chlorinated pool.Swimmers can make a difference, too. By simply showering before they get in the pool, they wash off much of the organic material that reacts with chlorine to produce toxic byproducts. Swimming, Kogevinas added, is still healthier than not exercising.
I'm pretty sure I'm dying of cancer anyways... i don't think there's a thing you can do in life that hasn't been linked to cancer in some obscure study so what's the worry with swimming?
Oh and I forgot to mention a couple more things:
1) These pools are public pools, meaning people who use them are less likely to be people who take care of them (as opposed to the high school pools I swim in for my practices)
2) There were only 3 studies done by my count. In one of those studies:
3) These were also in Barcelona Spain. I'm not really keen on the regulations and rules, but perhaps the standards and rules are different between Spain and America?They identified more than 100 chemical byproducts in the water. Many were toxic. Some had never been found in swimming pools or in chlorine-treated drinking water.
I think my take away at this point is if I find myself in a pool where I'm having problems breathing or the chemical balance is clearly wrong I'm going to get out. It's not worth the risk.
Many of our oldest members have probably swum in chlorinated pools for many years. Of course we don't know their medical histories, but any of you who have attended a large Masters meet will agree that these members all look fantastic! I got curious and just ran some numbers. Of our 2010 members as of today, here's how many we have in our upper age groups:
i am very distressed by all the inhalers i see on deck during any age group practice session. again, not science, just an observation. i also know that the air feels quite "heavy" around a lot of pools i've visited.
Still haven't read the original source articles, so with that in mind:
It isn't just 3 studies. Chlorinated DBPs (disinfection by-products) were first detected decades ago. Look in almost any textbook on water treatment (drinking, sewage) and you'll find a section on it. Many of the chemical listed have been identified as potential or probable human carcinogens. Nothing controversial about any of that. Heck, non-swimmers' greatest exposure level to volatile chlorinated DBPs like chloroform probably happens in the shower (hot water will increase the vapor pressure of volatile chemicals).
What is controversial is the degree to which environmental carcinogens actually contribute to incidences of human cancer. Some dismiss it as negligible, others do not. Due to the long lag period for cancer, it is hard to assign "blame," so to speak, from epidemiological studies. I suspect the paper is aimed at investigating this aspect of swimming pool chlorination.
Focusing on cancer is pretty understandable: it is a scary disease and, from a regulatory standpoint, there is no threshold level for carcinogens. That implies that guarding against cancer will guard against other health effects.
But with respect to pools, personally I am much more concerned about those other effects. I'm with Kirk: if you are having trouble breathing, it isn't good, and not just because of cancer. Most people know (or they should) that repeated high-intensity exercise in the outdoors during ozone-alert days will reduce lung function permanently; it isn't hard to imagine the same thing happening in swimming pools due to chlorination DBPs with long-term exposure. People in sensitive populations (eg asthmatics, people with COPD) will be even more at risk.
I had to smile at the phrase about "investigating alternative methods of disinfection." They've been known and used for years. In some -- maybe most -- cases they are more expensive. I'll have to ask my coach (who is also the facilities manager at the pools where I usually swim) about the economics of the uv and ozone treatments that he uses, and any other info about it.
Ultimately, I don't think any of us who love swimming would stopping because of this. I know I won't. However, I agree that I'd like to see more attention to this issue and a bigger effort to provide (less toxic) alternatives. I don't know of any non-chlorine pools in my area of the country (Cincinnati, OH). Those of you who have a choice are lucky.
Someone made a very good point that allayed some of my fears about this. If this were a really large risk, I think we would have heard some news indicating that swimmers have a much higher rate of cancer vs. the general population. I have not heard anything like that. In fact, I have only read stories about how swimmers may live longer as result of their participation in swimming.
Chlorinated drinking water??
Methane gas in drinking water??
What is safe to drink.
Margaritas?? We use ice cubes made of chlorinated water.
as already noted, the risk (if any) is trivial compared to the benefits of swimming, so....keep swimming, don't worry about it
regarding the "new" study (part of a trilogy published September 2010)....
From the study...
"Swimming is not associated with DNA damage."
"Levels of disinfectant byproduducts in swimming pool water are not necessarily higher than those in drinking water."
"brominated DBPs are generally more genotoxic and carcinogenic than chlorinated DBPs"
(DBP = disinfectant byproducts)
Chlorination is not the problem according to the study (regarding statistically significant changes).
Bromination may be. Higher levels of exhaled brominated trihalomethanes were associated with increased numbers of micronucleated lymphocytes, but not in changes in micronucleated urinary tract lining cells. 'Urine mutagenicity" increased in association with higher levels of exhaled bromoform (determined by mutagenic effect of urine samples on the bacteria Salmonella).
May Be! Increasing cancer risk from indoor pools and absorption through the skin and lungs is HIGHLY speculative. Direct data does not exist...ie, data showing an increased cancer risk in cancer rates (vs a suspected biomarker effect from brominated compounds).
Study design, by the way, involved pre-swimming testing vs post-swimming testing, wherein swimming meant 40 minutes of undefined swimming in an indoor pool in Barcelona, Spain in 2007. Doing jumping jacks, pushups and situps, or merely sitting, near the pool for 40 minutes may have produced similar results!
Last edited by makesense; September 14th, 2010 at 12:56 PM.
Another article on the same study:
I ain't as good as I once was
But I'm as good once as I ever was
During the polio epidemic Winnipeg 1953 the pool was loaded with chlorine. The Canadian swimming Champioships were held there. There was so much chlorine in the pool your eyes turned red when you went into the pool area.
I remember years ago a friend told me "Lui, I think it's cool that you swim but I would worry about the chlorine. It might cause cancer". While he was telling me that he was smoking a cigarette