But heat destroys chlorine!

Maybe it is the hot water mixing with the cold in the shower but I have certainly been in parts of the world where there is high chlorine in the water and when I have had a hot shower the smell of chlorine is overpowering, so it certainly is in the atmosphere of the shower, and given that the pores are open in the skin the chlorine is ingested.

Not very scientific I know, but it has been enough to cut short my shower.

I am pretty sure that there have been studies done measuring the amount of chlorine ingested in this manner.

I'm afraid that this is question , and the answers are typically those of non-chemists. In fact chorine ( Cl2) is a very reactive and dangerous gas that reacts directly with water to form hydrochoric acid ( HCl); quite the same acid we produce in our own stomach). The ion in HCl is called a chloride-ion ( and not chorine!). The smell of 'chlorine' in aquous solution may come from other compounds like HOCl ( hypochlorite) or NH2Cl ( chloro-amine). These latter compounds may do harm in high concentrations but are , at low concentrations, also present in desinfected water of at lot of swimming pools.

hans Krul

Thanks for this explanation Hans. Interestingly I have experienced showers using the same source of water and when one of these 'special' filters were fitted the 'chlorine' type smell could no longer be detected.

Would the explanation be that it is removing the compounds that you referred too? Thanks.

I live in the northeastern US along the Hudson River and have been showering in water that smells of chlorine for years. I hate that smell in the water and since my hair is not a naturally blonde color :) I was really only thinking about how it affected my hair. But I also only drink bottled water thinking that water that needs to be so highly chlorinated to pass into my home can't be so great to drink. So that's my comment but my question is, what are the studies to show what kind of effect this is having on our bodies?

As a side note, I enjoy your efforts very much Warren to keep people healthy and informed.

I've been in the water treatment business for just about 18 years and became a Water Quality Association Certified Water Specialist first in 1993, a study that took me two and a half years. Fewer than five percent of people who make their living full time in water bother with certification - it is a complex and difficult study.

A twenty minute shower will allow your body to absorb just as much chlorine as drinking two liters of the same water. Also you should consider that when chlorine is added to water that contains humic acid (leaf dye or tannins) and almost ALL waters do, the halogenated compounds inherent in chlorine interact and form trihalomethanes which are carcinogenic over a long term (20 years or longer) IF you have such a genetic predisposition. These chemicals can also pass through your skin. Those little shower filters containing carbon and/or KDF 55D will greatly reduce chlorine but have a *very* limited effect against trihalomethanes.

All in all it is deemed a far lesser evil to use chlorine than not to. History is full of tales of epidemics caused by water borne pathogens - cholera, typhoid, dysentery, hepatitis, malaria, etc. to name only a fraction. Even if we could ensure totally safe water exiting our treatment plants, without chlorine in the distribution pipes there is a real potential for organisms to aspirate into our water through older or fractured pipes under our streets. So REALLY thank goodness we have chlorine. There would be terrible suffering without it.

To deal with both chlorine and trihalomethanes effectively it is best where the water enters your house to install a large backwashing filter which contains one and one-half cubic feet of coconut shell carbon (as opposed to lignite or bituminous coal based carbon). Adding six to eight pounds of carbon into the top of your water softener acts much like a shower filter – it’s a cosmetic solution and just isn’t enough to have any real effect against trihalomethanes.

For you scientists out there here are the numbers: twelve ounces of either coal or coconut carbon will reduce chlorine effectively for up to 20,000 US gallons, but only effectively reduce trihalomethanes for ~ 800 US gallons (coal) or ~ 1200 US gallons (coconut shell). One cubic foot of carbon weighs approx. 35 lbs. and there are 16 ounces to a pound. The average North American (on a water meter) uses 60 US gallons per day (teens 75 US gal.).

So for a family of four you ought to have your 1 ½ cubic feet of coconut shell carbon replaced yearly. (Shameless plug) IF you do elect to fix your water be sure to deal with a Certified Water Specialist – you’ll get a scientist… all others are sales people. For a CWS near you see www.wqa.org

Warren,

Once again your lack of impartial science backed facts has let you down.

Genuine scientists do not peddle opinion nor old wives tales. For example,what does the 'pores are open' mean?

To be taken seriously you should rather have been able to provide the relevant facts as included by the authors of the two science based comments above (from Steve and Hans) rather than a lot of subjective pseudo science as contained in your answer.

Sharon

I don't profess to be a scientist Sharon. I make my comments based on common sense and experience. I do not profess to be an expert on this particular subject and I am sure that most of my readers realize this.

However, as a lay person I do know a few basic things about this subject based on personal experience

1. Is that in some parts of the world you get a strong smell of chlorine when you have a hot shower. In that regard I am sure that it is not good for you.

2. That some types of filters will remove that smell.

3. That when you have a hot shower that it is easier for chemicals to pass through the skin into the blood stream. What I mean by 'pores are open' is simply that when the pores of the skin are exposed to hot water they do dilate thus making it easier to ingest chemicals through the skin. I don't think that a scientist would dispute that. There seems to be plenty of evidence around to support this notion.

Maybe these observations tie in with 'old wives tales' but the experiences are real.

The reason why I don't block comments on this blog is that it gives other readers who are more knowlegeable than me to put the record right if I am wrong on any issue. For this, I am grateful to the two posters that you refer to for elaborating on some aspects of this topic.

Nonetheless, the general principle of my comments still remains valid, and that is an effort should be made to eliminate these dangerous chemicals from your shower water. Many people are not even aware of these dangers so if my initial comments help increase this awareness even if they are not 100% technically correct, then I for one am quite happy about this.

Not many people are scientists, so by voicing an opinion as I do it does provoke people to think further about a subject that they may be interested in and perhaps prompt them to do some further research.

This is the value of the blog.

Dear Warren,

Several years ago ( if I recall well it was in 2002, or was it 2003?) you published at your web site a comprehensive report on optimal diet and weight loss – it was entitled “Weight Loss... Easy, permanent... natural and healthy! Learn how to normalize your weight without ever going hungry whilst enhancing your overall health!”

I was more than pleased to read this report then – indeed, it had decisively influenced my decision to start using the Atkins’ principles in my diet. Lot of new discoveries have meanwhile taken place in both the medicine and the nutrition fields and, again if I recall well, you promised sometime ago to revise your report in the light of these latest findings.

Is there any prospect of your releasing a new report soon on this issue? Specifically, I’m interested to hear your opinion about the work of Patrick Holford on diet and optimum nutrition;I’ve read some of his books and, as a layman, I have impression that they are pretty convincing and well researched.

Mihailo

You are quite right...a lot more has been learnt since I wrote that report a few years ago, and yes, I am going to revise it. It is high on my priority list. I am aiming to complete it within the next 30 days. Thanks for the prompter.

Warren is right, letters behind your name do not mean one is qualified to make an assertion on a particular topic. Although in this case the initial comment was slightly misleading and required further elucidation, Warren is a very astute man, which is reflected in many of his subjective and objective commentary. Being highly qualified and specialised, like myself can often mean that
1. educational institutions brainwash us, or
2. we create science by finding exactly what we are looking for, only to find out 100 years later that the earth is not in fact the centre of the earth.

"All I know is that I know nothing" Socrates

Thank you for these comments Joseph, Indeed,the more we learn, the more we realise how little we know and how much more there is to learn.

You are so right about some of the educational institutes and some of the people who graduate from them. Some of the medical schools are particuarly bad when they refuse to accept some of the fundamental truths of life including the age old saying that 'food is your medicine' and is the path to wellness, not drugs designed to block the symptoms of disease.

The good thing is that more and more people are becoming 'enlightened' and understand that prevention, not intervention is the key to health and happiness.

Hi Warren,

Just want to reinforce the notes on the use of chlorine by Hans and Steve. The SMELL of chlorine in your water is NOT chlorine gas - or you would be dead, just like the soldiers in the front Lines in the First World War!

What you are smelling is the additive REACTING with other substances - particularly biologicals. In other words, and to be absolutely clear, the greater the loading of stuff in the initial water, in the delivery pipes, in your house pipes etc, the greater the "chlorine" smell.

To be controversial, the greatest contributor to the health of the world has been the Public Works Engineer rather than the surgeon or the physician! I think it has been about 100 years since we have had a typhoid epidemic in NZ, in part due to the chlorination of public water supply.

However, those chlorIDES (not the INE) and bi-products can also be absorbed and some are not healthy. Filtration is the only satisfactory way to deal with them.

Steve's comments on the halogen bi-products (chlorine gas is one of the halogens), is important to re-read and understand - as are the comments on filtration. May I ask you to discuss this with Dr.Munem, and then summarise his reply for us?

Science - important; commonsense also. There is little "chlorine gas" in solution, left in our water when it gets to the tap in most towns in NZ.

Finally, most bottled "spring" water is drawn from the general public water supply (not all such, of course) and it will likely be no more/less offensive than tap water - except - that it has been passed through activated charcoal to remove the smells.