Long term Health Effects

Larry, Your comments sound a lot like former Surgeon General Koop. He has riffed on a couple of occaisions about fanciful theories on this chemical or that substance being "harmful" based on slender scientific evidence. The bottom line for him is that we as a society spend alot of time worrying about potentially toxic substances, and spend significant amounts of money trying to remedy their theoretical effects, when he feels the effort and money would be better spent on other health issues with much clearer and more significant impacts (e.g. obeisity, lack of exercise, tobacco use, etc.) It's a perspective worth considering. Matt

Matt quotes Dr. Koop in saying that we as a society tend to get caught up in the small stuff (health-wise), while ignoring the big picture (obesity, smoking, etc.). In general, I agree, but, in the case of the potential for long-term harm by exposure to chloramines, I am frankly surprised by the lack of real data. Certainly, there are plausible reasons for concern (nicely discussed on Dr. Rushall's website, URL listed previously on this thread. In addition to adult swimmers (more importantly, actually), there is the issue of young swimmers, many of whom spend up to 4 hours (sometimes more), several to many/most days per week, for 10 or more years, all while they are in a biologically vulnerable growth and development mode. My interest in the subject was first triggered by the obvious association with asthma (in most cases, not a huge problem). But my interest really went up when I started noticing little bronze plaques, memorializing club swimmers (teenagers) who had died of cancer, affixed to walls and benches at local competition pools. Then a 15 year old girl on one of my two daughter's teams was diagnosed with (and later died from) rhabdomyosarcoma. Then a 12 year old on my other daughter's team was diagnosed with acute leukemia (fortunately now in a chemotherapy-induced complete remission). Then a 19 year old daughter of a good friend (who had been an age group and senior swimmer for 10 years) was diagnosed with a very rare type of ovarian cancer. She suffered multiple recurrences, but is now doing well following extensive surgeries. So I wondered: Has anyone ever looked at the incidence of childhood cancer in swimmers, compared to similar groups of kids, who are not swimmers? To my surprise, I found that, no, this has never been studied and reported. How many excess cases of childhood cancer would it take before it was "worth it" to change from chorination to ozonation? 1 per year? 10 per year? 100 per year? How many excess cases are currently attributable to swimming/training intensively in chlorinated pools? Honest people may disagree about the first of the above questions, but I don't see how anyone could disagree that it's not important to answer the 2nd question. Is there any increased risk? What is the magnitude of this increased risk? What would it cost to bring the risk down to acceptable levels? No one knows. And this is a pity. - Larry Weisenthal

Thank you Larry, for a very thoughtful and thought provoking post. I too, am becoming alarmed at the obvious negative impact upon my body by obsessively excessive amounts of chlorine. ( Asthma,sore eyes, itchy skin, allergic reaction, etc.) To repeat myself, IT'S A POISON !!! Bert

Thank you for your post Larry. I find it hard to believe that some post graduate student out there couldn't find academic support to do a well designed epidemiological study of this issue. I hope that organizations such as USMS would be willing to help survey members for such a study. Anecdotal tales are poor indicators of trends. It would be nice to have data.

Another interesting fact in this would be to look at indoor vs. outdoor pools. Ventalation systems for Natatoriums have long been overlooked, one facility I worked at exceeded the recommendation/requirement on air movement, yet some days the air quality inside was horrible. Obviously most outdoor pools don't have this problem. Fresh air/air movement is a very importatnt factor in reducing chloramine buildup, pbut as I said it is often overlooked. I have seen people who were asthmatic swimming at outdoor pools and they were actually able to get rid of their inhalers, yet it seems indoor pools with bad air may have a tendency to trigger asthma type problems. Ozone disenfection is not without its health risks too, as is Iodine and Bromine disenfection. Jeff

It looks like someone is already starting this study. See below: Dear Swim Coach, I am an environmental health scientist conducting research on the potential health effects associated with swimming pool chemicals. I am working with the American Chemistry Council, a coalition of companies that includes manufacturers of swimming pool chemicals, to improve the estimation of exposure to swimming pool chemicals. In cooperation with the U.S. Environmental Protection Agency, we have designed a telephone survey for swimming club coaches to obtain information about the amount of time amateur swimmers practice and other information relevant to swimmer's exposures to chemicals. This information may be used in future regulatory decisions about these chemicals. Your email was provided to us by United States Masters Swimming, as a coach who is knowledgeable about swimmer's practice habits. If you would be willing to participate in the telephone survey, please reply to this email (address is rreiss@sciences.com) with your telephone number and typical time of day that you can be reached (include time zone). Please note that the survey is completely confidential, and we will not provide your names or swim club affiliations to either the American Chemistry Council or the Environmental Protection Agency. Thank you for your help on this important project. Sincerely, Dr. Richard Reiss

I've read some studies recently (and an article in the Washington Post from a month or two ago) linking chlorination byproducts (trihalomethanes, or THMs) to an increased risk of miscarriage in women. I think one study in California found that the risk of miscarriage rose from 7% to 15% among women who were drinking lots of tap water with relatively high THM levels. My question is, what does this mean for those of us who swim in chlorinated pools all the time?? I have seen a lot of information related to asthma and cancer, but does anyone know of any studies regarding miscarriage? It is a little frightening, especially since doctors recommend swimming as a good exercise for pregnant women (likewise for asthma sufferers of course). It may be that the risks are very slight, but this is something I am reluctant to take much risk with.

I too saw the Washington Post article and was concerned by it since I live hear and drink that water. I'm not a chemist but from my understanding it was referring to chlorination byproducts that are the result of the chlorine in water mixing with organic nutrients, e.g. fertilizer runoff in the Potomac River in the summer time. They pump in more chlorine to deal with the contaminants and the byproduct levels can get high. It's seasonal and local and has been implicated in a lawsuit by a group of Virginia women who had miscarriages. I think the chlorine in and of itself was not factor in the miscarriages. So as long as pool water isn't similarly contaminated, it shouldn't be a problem for swimmers.

Well, that is just the problem. The chemistry in a pool is a lot more complicated than water with nothing but chlorine ions floating around. As any pool operator will tell you, the more a pool is used the more chlorine must be applied, and the more difficult management of pH and other factors becomes. That is because lots of organic nutrients wash off of body and hair and react with chlorine, making all sorts of nasty stuff. It is these chemicals that Larry referred to in an earlier post, and what I think is most worrisome.

I actually work with someone who did her graduate work on THMs in treated water (THMs being the byproducts that Philip mentioned). She studied women's blood THM levels and found that they increased significantly after women took showers (but she assures me this does not mean there is any risk associated with showers!!). So water that is more highly chlorinated (like a pool...) will cause greater increases in THM levels in people exposed to it. These levels do drop after a few hours out of the water. But the THMs are there, but no one seems to know at what level they might become a measurable risk for different health effects. It seems that the acute exposure is what might be linked to miscarriages. I'm sure it is less of a risk than say smoking during pregnancy, but it is easy to get paranoid about all of these little risks adding up when you swim and take 2 showers every day... not to mention drink a lot of tap water!