Are there alternatives to chlorine in swimming pools?

It's common for chlorine to take the blame for many irritations or problems that arise from using swimming pools.

We're probably all familiar with at least one of the common side-effects of swimming: sore eyes, skin irritations, fading swimming costumes, green hair, and that lovely smell that lingers until you've had a good shower. But the chlorine itself, when used at the recommended low levels, is perfectly safe.

Why do we need chlorine in pools?

When it's added to water, chlorine breaks down into two chemicals: one kills bacteria almost instantly, the second stays in the water killing any bacteria brought in by new bathers. In spas, it is not possible to drain and refill a pool or hot tub every time a new bather arrives, so water not only has to be sanitised before it gets into a pool, but the water must stay clean throughout the day. With new bathers frequently entering pools, bringing bacteria with them, this residual cleansing aspect is essential.

What alternatives are there?

The two most popular alternatives to chlorine for use in pools are ultraviolet filtration and ozone generators. UV Filtration Water can be irradiated by ultraviolet light, which kills existing bacteria. This method can sanitise water as it enters a pool, but has no residual properties, so cannot act to kill bacteria brought into the water by new bathers.

Ozone

Ozone is an effective oxidiser, so can be used in water sanitisation. Like UV filtration, ozone can only assist in sanitising water on entry, and does not offer a residual solution. Neither ozone nor UV treatments are stand-alone solutions. They must be used in conjunction with a sanitiser that stays in the water. So although these methods claim to offer an alternative to chlorine, they must work in conjunction with a low level of chlorine in the water in order to meet safety standards. However, as the levels of chlorine used are very low, these solutions do avoid the risk of over-chlorination and its effects.

What are the dangers of chlorine?

By far the biggest risk involved in the use of chlorine is poor use, where chlorine levels are not monitored correctly. There are very few dangers to your health when chlorine is used correctly, so the main hazard of chlorine use is the person responsible for getting it into the pool in the right amounts. If the correct amount of chlorine is used in a pool, the pool's pH (a measure of how acidic it is) will be at the recommended level of 7.4: the pH of your own tears. If the chlorine level in the pool is not correct, this can cause strong chemical smells, sore throats, skin irritations, and red eyes.

Cosmetics, and sun and body lotions, can also cause problems as they contain compounds that can react with chlorine, creating an irritant. If you have bleached or highlighted hair that turns green in pools, this is likely to be caused by the presence of copper in the water, suggesting that the pH is too high (eroding copper fittings), or copper-based algaecides are being used, not that chlorine is responsible.

Respiratory effects

Some studies have suggested that children may be more likely to develop asthma if they swim regularly in chlorinated pools. When chlorine levels are too high, sweat, skin, and other organic compounds can react with chlorine, producing trihalomethanes, the harmful fumes that can cause irritation to the eyes, skin, and respiratory system. The studies show that children in European countries where indoor chlorinated pools are easily accessed had a higher rate of respiratory complaints such as wheezing and asthma, than less developed areas.  SEE NOTES BELOW

However, these findings may show the effects of over-chlorination, but do not suggest that a low level of chlorine is harmful. It has been proven that children with asthma benefit from exercising in the warm, humid air of a pool, as it is less likely to trigger symptoms, and swimming has significant health benefits. So rather than banning your children from swimming, just try to be alert to any warning signs of over-chlorination. For adults there is much less to worry about, as a developed body is far less likely to be affected.

Environmental damage

As media attention has begun to focus on the adverse effect that we are having on our planet, you may have seen information suggesting the harmful effects of chemicals such as chlorine. However, it is industrial uses causing the problems, as the chlorine levels used in bathing (and drinking) water are too low to have such an impact. Pools are rarely emptied directly into nearby streams, as waste water systems channel used water to treatment plants or regulated outlets. Although it cannot be denied that chlorine can have negative environmental effects, you are likely to be introducing more chlorine to the environment by watering your garden, than an occasional trip to a spa.

What are the advantages of chlorine?

The bacteria in an un chlorinated pool are more likely to do your health damage than chlorine itself, and the health benefits of swimming and bathing far outweigh any proven adverse effects. Over-chlorinating may make your eyes itch, but if you consider that chlorine eradicates micro-organisms that carry water-borne diseases such as dysentery, hepatitis A, and cholera, it is easy to see the benefits.

Where can I find out more?

Your local pool or spa will be able to tell you exactly how they sanitise their water. Just be aware of the warning signs of over-chlorination.

Tips

* Remember to shower before and after entering any pool or tub.

* Remove all make-up, body lotion, sun cream, and hair products before entering the water.

* Be wary of a pool that has an overpowering chemical smell.

* Swallow as little water as possible

* Be aware of any irritation to your skin or eyes.

* Watch for any irritation or wheezing that your child may experience soon after swimming.

NOTES FROM ISRM (Institute of Sport and Recreation Management) dated 1/9/09

 

Collectively these findings suggest that swimming is an appropriate and beneficial activity for asthmatics. Asthma sufferers are less likely to experience breathing difficulties with swimming than with other forms of exercise and swimming training may improve their condition. It is very likely that these factors have attracted asthma sufferers to the sport of swimming and hence indirectly led to a higher prevalence of asthma among elite swimmers than among elite competitors in other sports. Further research will be required before definitive statements can be made about any link between chlorinated swimming pools and the risk of asthma. At present the evidence regarding a link is weak and unconvincing and swimming should continue to be recommended to asthmatics and non-asthmatics alike as an excellent form of exercise for maintaining fitness and health.

By David Stensel, PhD

David Stensel has a PhD in Exercise Physiology. He is a member of the Exercise Physiology teaching and research group within the School of Sport and Exercises Sciences at Loughborough University, UK. His primary interest concerns the relationship between physical activity and health. He is the author and co author of many authoritative texts on sport, physiology and health.