Making a Splash with Chlorine

Allyson Tighe
23 January 2012

You’re probably most familiar with chlorine as what you stank of for a day or two after that pool party at your friend’s parent’s condo, or what caused your swimming suit to fade in colour and disintegrate to an embarrassing piece of pool-wear.

Did You Know?
Pool smell is due, not to chlorine, but to chloramines, chemical compounds that build up in pool water. Chloramines result from the combination of two ingredients: (a) chlorine disinfectants and (b) perspiration, oils and urine that enter pools on the bodies of swimmers. Chlorine: The upside

Ranking as one of the smallest elements, chlorine, as well as chlorine compounds, has all kinds of activities in nature. It can be found in the blood, skin, and teeth of all humans, and in the form of hydrochloric acid in our stomach. It is also necessary for the life of plants and animals. There is even a species of tree frog that produces chlorine in its skin!

As well as being used to decontaminate public swimming pools, chlorine is used to purify drinking water. It has the ability to kill harmful water-borne bacteria and viruses that could otherwise lead to serious diseases.

Chlorine solutions that are added to water break down into two compounds; hypochlorous acid and hypochlorite ion. Both of these chemicals can kill microorganisms like bacteria by destroying their cell walls. It’s safe for humans and other animals though because animal cells don’t have cell walls.

Did You Know?
The smelly chloramines in pool water are formed by the reaction of hypochlorous acid with ammonia. Ammonia, NH3, is a component of sweat and urine So if chlorine does so many useful and beneficial things, why does it seem to wreck havoc on our body and bathing suits after we swim?

Chlorine: The downside

As a fitness instructor and health librarian, Orvie Dingwall knows that swimming can be an incredible workout and a great way to relieve stress. Her competitive synchronized swimming, lifeguarding and instructor days, however, remind her all to well about the downsides of chlorine.

She explains, “Swimming is a fantastic cardiovascular low-impact activity that utilizes the muscles of the upper body, lower body and core. The biggest disadvantage is swimming in chlorinated pools because the chlorine is so tough on your skin, hair, eyes and bathing suits.”

First of all, hair shafts are made up of two layers, the inner cortex, which is protected by an outer layer called the cuticle. The whole hair is coated by a protective layer of oil called sebum. This is one kind of oil you don’t want to wash away since it retains the moisture in your hair.

Unfortunately, chlorine in swimming pools strips sebum away, leaving the hair unprotected. This causes the hair to dry out and crack, resulting in split ends and the “frizzies”.

Did You Know?
Chlorine gas appears to be yellow-green in color. The same kind of thing happens with skin. When chlorine messes with the natural oils protecting your skin, it leaves it vulnerable to dehydration, leaving your skin dry, flaky, and itchy.

And what about those fading and disintegrating bathing suits? Chlorine is also what we use as household bleach, commonly used to whiten and brighten clothes.

Clothing fabrics that are exposed to any amount of bleach will eventually fade and the fibers will sooner or later break down as well. However, good quality swim suits are now made from chlorine resistant materials which hold up better in chemically treated pools.

The best way to protect yourself against these annoying effects of chlorine is to protect your hair (wear a swim cap), wash your hair and skin and rinse your bathing suit as soon as possible after getting out of the pool, use tons of conditioner, and moisturize your skin as much as possible.

Most of the adverse effects of chlorinated pool water are just annoying, but it has recently been shown that exposure to the chlorine in swimming pools can lead to asthma. Although this is only after a lot of exposure in poorly ventilated areas, it is still a significant risk to children and people who work in pools.

Did You Know?
Chlorine was used during World War I as a choking (pulmonary) agent. Luckily, some public and private pools are now switching to ozone to purify the water, which is just as effective, but has none of the irritating effects of chlorine, so you can enjoy all the benefits of a good swim without all the annoying side effects.

Learn More!

Bernard A. et al., Environ. Health Perspect., 2006

Allyson did her B.Sc. in Genetics at the University of Western Ontario (UWO), and is currently working on her Master's in Physiology, also at UWO. Her work focuses on spinal cord injury and scar formation, and how to make the cells that make up that scar (astrocytes) more hospitable to nerve regeneration. Allyson is also learning whitewater kayaking, although most of her time is currently spent underwater and inhaling a lot of water at the moment.

Allyson Tighe

I completed my BSc and MSc at The University of Western Ontario, and am now a scientific writer and editorial assistant in Toronto. I am an expert risotto maker, a decidedly non-expert runner, and a WeatherNetwork junkie.

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