Chlorine Cancer Link

[svspa]

I just heard a sound bite on the news the other night about chlorine and a link to higher cancer risk. Specifically I think they were talking about bladder cancer. Beyond the link to drinking water they said something about skin absorption.

Did anyone hear this? Anyone know any more info, was this a new study? I know there were some studies back a few years ago but I am not finding any info on the web about any new study.

Seems this would be of interest to us hot tubbers and our "relatively" high levels of chlorine used in hot tubs. As compared to drinking water levels at least. While we strive to soak in as little chlorine as possible it still seems we would be exposed to higher levels than shall we say someone who bathes frequently in chlorinated tap water.

No worries, I am sure we are all quite safe, certainly more safe than we would be without a reliable sanitizer for our tubs. Just thought this would be a topic of interest to us all and wondering if anyone has more info.

Steve

[Brewman]

Have not heard of that one, but I did read where bromine was linked to cancer.
 Of course sacharine was also linked to cancer to the point it was banned, and then they found out that it wasn't after all.
 If you want to look hard enough, you can probably link anything to cancer.  

[anne]

Well, here's my 3 minutes of internet research. Lots of people seem to think that there is a link between chlorine and both cancer and heart disease. But is also seems to me that there are so many potential carcinogens around today that there are plenty of other things we are exposed to daily that will kill us, too. I'm not going to stop soakin'!

ftp://http://www.internethealthlibrary.com/Environmental-Health/Chlorine-and-cancer.htm

ftp://http://www.cnn.com/HEALTH/9706/17/nfm/nfm.water/

ftp://http://www.dhfs.state.wi.us/eh/ChemFS/fs/chlorine.htm

ftp://http://www.ghchealth.com/chlorine-cancer-and-heart-disease.html

[Dr. Spa™ Ret.]

Some years ago, carrots were proven to cause cancer (truth!)

[Bama]

Many years ago, it was reported that plastic baby bottles were linked to cancer.

[Vermonter]

I just heard a sound bite on the news the other night about chlorine and a link to higher cancer risk. Specifically I think they were talking about bladder cancer. Beyond the link to drinking water they said something about skin absorption.

Did anyone hear this? Anyone know any more info, was this a new study? I know there were some studies back a few years ago but I am not finding any info on the web about any new study.

Steve,

I get a daily "e-news" covering many water related topics and the study you mention was, indeed, an article released yesterday.  My "e-news" was from a Reuters summary of a Scientific American publication that appears to have had its source be the American Journal of Epidemiology, January 2007 (whew)  - the link is:

http://www.sciam.com/article.cfm?chanID=sa003&articleID=D13DDA85502E18DAC4BCA8C4C429B86C

The actual Journal of Epidemiology abstract is found at:

http://aje.oxfordjournals.org/cgi/content/abstract/165/2/148

A couple of (my) observations...

First, the study is reported as "the first to suggest", etc. - i.e. it is not definitive.  It does not seem to address tub make-up water and other considerations.

Second, it is significant to note that the "cancer link" is not specifcally for chlorine, but rather with the disinfection byproducts (DBPs) that result when chlorine is added to water that contains certain compounds (in this case, organics of a certain type).  

DBPs actually have a number of forms - the group cited in the study are the Trihalomethanes (THM's).  THM's have been reportedly linked to cancer for years.  Many drinking water suppliers are switching away from the use of "straight" chlorine to chloramines (!) or ozone, followed by chlorine or chloramines in an effort to reduce DBP levels in their treated water and to comply with more stringent EPA regulations.

 In January of 2006, the EPA finally published a couple of regulations that had been in the works for years - they became effective (implemented) in October of 2006.  The two regulations are separate, but related.  

One regulation, while unrelated to the initial subect of this thread, is called the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR or LT2 rule) -   http://www.epa.gov/safewater/disinfection/lt2/index.html  It deals with assessing the prevalence of Cryptosporidium in the source waters of nearly all Public Water Suppliers (PWS's) in the United States.  It is a rule I am very familiar with - my lab processes more than 2500 PWS source water samples per year for Crypto (and Giardia).  My company's website (www.analyticalservices.com - needs updating... -  has a summary page that gives an overview of the LT2 Rule.  That link is: http://www.analyticalservices.com/drinking_water/lt2update.html

The second regulation published in January and implemented in October (2006) is the one dealing with DBPs and is called the Stage 2 Disinfectants and Disinfection Byproducts Rule (DBP rule) -  http://www.epa.gov/safewater/disinfection/stage2/index.html

Both of the EPA links I gave are the "home" pages for the rules and include links that would enable you to learn more than you probably would ever want to know about the background and justifications for the rules.

Best,

Vermonter

[Chas]

You know Verm, (May I call you Verm?)

It's really nice to have you around.

Side note - I run my spa so that there is usually 1PPM or less when I soak. I think most of us do. I add Dichlor after I soak, and it is usually back down to <1PPM the next time I go to use it.

I also keep the pH at around 7.4 as do we all.

That makes our tub water MUCH better than the water many of us shower in, which most likely has more chlorine and variable pH. In fact, my delivery crew still reports that here in SoCal the new tubs end up close to 3PPM Chlorine when we fill them from the tap.

 8-)

[Vermonter]

You know Verm, (May I call you Verm?)

Hi Chas!

Just don't call me Ray  

Keep in mind that the issue at hand has to do with the THM levels in the water and not with chlorine (per se).

My understanding is that the amount of THMs produced for any fixed volume of water (i.e. one "fill" of a hot tub) is finite.  In other words, if X level of organics are present and if you add chlorine, you'll get y level of THMs (and other DBPs).  If you add double the chlorine, you'll still only get that same y level of THMs (once the reaction is complete).

If you are using city water that has been treated with chlorine, by the time you fill your hot tub (or get a glass of water), the complete THM conversion has almost certainly occurred, so I don't believe that adding more chlorine at any time after that will result in additional THMs - with respect to the THM precursors in the city water.

What I don't know (at this time) is whether any of the "contaminants" introduced by human use of the tub or environmental contamination (airborne chemicals, pollen, frogs, cats, dogs, turtle doves, margaritas, etc.) may release DBP precursors (in this case, THM precursors) that then might be converted by normal chlorine addition.    If this occurs, the obvious question is whether the dermal route of entry to humans is significant.   I have never looked much into what the THM precursors are - other than knowing that chloroform is one of the main precursors.

For what it's worth, I'll try to look into this a bit more (for anyone who is interested).

Vermonter (aka Verm)

[Reese]

Side note - I run my spa so that there is usually 1PPM or less when I soak. I think most of us do. I add Dichlor after I soak, and it is usually back down to <1PPM the next time I go to use it.

Chas, it is good to have you back around here as well!

Two questions for you:

1.  Awhile back when there was a poll about which sanitizer people used, I thought you reported using Brilliance bromine at home.  Did I have that wrong?
2.  If you did, why did you switch?

Don't let Steve know about soaking in <1 ppm chlorine, that will lump you in with the uneducated risk takers!

[In Canada eh]

DBPs actually have a number of forms - the group cited in the study are the Trihalomethanes (THM's).  THM's have been reportedly linked to cancer for years.  Many drinking water suppliers are switching away from the use of "straight" chlorine to chloramines (!) or ozone, followed by chlorine or chloramines in an effort to reduce DBP levels in their treated water and to comply with more stringent EPA regulations.

    The plant I work at switched to chloramination for that reason.  After ironing out the commissioning problems two years ago,  things seem to be working well

[svspa]

Thanks for the post Vermonter, it's great to have your expertise on the forum.

With so many of us using your dichlor dosing routine it's good to hear your educated opinion on these matters.

Like I said I don't think there is any reason for any of us to worry, but as you stated we don't know if during normal use of our hot tubs we may be exposed to those DBPs at any significant level. It will be interesting to see if any further studies help us understand this better.

BTW, while our water here in the silicon valley is treated with chlorine I get a 0ppm level when testing at my tap. Obviously the level is below the sensitivity of my taylor kit.

Oh well, I'm gonna go pound down a few hohos, smoke a cigarette and ponder this situation  

Steve

[Vermonter]

    The plant I work at switched to chloramination for that reason.  After ironing out the commissioning problems two years ago,  things seem to be working well

Out of curiosity, did you notice any more Total Coliform positives in your distribution system after your switch to chloramines (assuming that in Canada, as in the US, water systems have to routinely sample a number of points in their distribution system for total coliforms)?

Vermonter

[In Canada eh]

Out of curiosity, did you notice any more Total Coliform positives in your distribution system after your switch to chloramines (assuming that in Canada, as in the US, water systems have to routinely sample a number of points in their distribution system for total coliforms)?

Vermonter

Vermonter,

  Initially yes,  but because of the change over in disinfection process the entire distribution system was under a boil water advisory.  Strangely, part of the reason for the change over was due to the number of coliform "hits" in the distribution system.  Two years have pasted and things are now alot better



And yes, water samples are collected twice weekly, there is a formula for the number of samples based on the population being served, but we collect approx 150 per week

[Vermonter]

Strangely, part of the reason for the change over was due to the number of coliform "hits" in the distribution system.  Two years have pasted and things are now alot better

Prior to the switch to chloramines, I gather you were on either chlorine gas or sodium hypochlorite?  
Do you happen to know what your THMs (or DBPs - total) were prior to and after the change to chloramine?
Given your DBP issue, I also assume you are on a surface water source?

Thanks - not really related to Hot Tubs, but it is of interest to me from our consulting perspective.

Vermonter

[In Canada eh]

Prior to the switch the plant used chlorine gas, sodium hypo was used only for zebra mussel control.  Yes you are correct to assume a surface water source, we draw from Lake Erie, intake is one mile off shore and is in 35 feet of water depth.  As far as disinfection by products before and after I can get the info from one of our operators if your interested.  I do carry a water treatment licence but I am primarily involved in plant maintenance, pumps, instrumentation etc. etc.