
Chlorine Toxicity: What Is Known
1. Exercising competitive swimmers absorb toxic levels of chlorine products in
the course of a training session.
2. Training two or more times a day will not allow the toxins to be completely
cleared from the body in most swimmers.
3. Children inhale more air per unit of body weight than adults.
4. Young children absorb relatively greater amounts of toxins than older
swimmers and therefore, are at greater risk.
5. In hyper-chlorinated pools, even dental enamel can be eroded because of
the increased acidity in swimmers in training.
6. Exercise intensity and number of sessions increase the toxic
concentrations in competitive swimmers.
7. Greater toxin absorption occurs through the skin than through breathing.
However, the breathing action alone is sufficient to cause
hypersensitivity and "asthma-like" respiratory conditions in at least some
swimmers.
8. Over chlorination is particularly hazardous to the health of swimmers.
The Age
November 23, 2007
The above "The Age" extract is from the following link: http://www.asthmaqld.org.au/content/?action=getfile&id=227
A new Belgian study is linking swimming pool chlorine to the asthma epidemic which is spreading in developed nations.
Researchers at Brussels' Catholic University of Louvain say when chlorinated water reacts with organic matter such as urine or sweat it creates trichloramine, a gassy, easily inhaled irritant.
Trichloramine is already known as a trigger for three proteins that destroy the cellular barrier protecting the lungs, making it more prone to an asthma attack.
The researchers have tested the blood of hundreds of young pool swimmers, finding higher than normal levels of the proteins.
The levels rose even when people merely sat beside the pool.
The scientists say the study suggests a move towards non-chlorine based disinfectants or improvements to water and air quality control in indoor pools.
Chlorination is used to kill swimming pool bacteria
Scientists are calling for more research into levels of chemicals in swimming pools after it was found they were significantly higher than in tap water.
Earlier studies have suggested the chemicals could harm unborn children, and experts have moved to reassure pregnant women that swimming is safe.
The study calls for chlorination levels to be reduced as a precaution.
Many antenatal classes involve regular swimming sessions, as this can provide much-needed exercise without overstressing the joints.
Chemicals such as chlorine are added to pools in higher concentrations than in tap water in order to kill off potentially harmful bacteria.
A small snapshot survey tested water from eight pools in the London area, and published in the journal Occupational and Environmental Medicine.
It found, as expected, that levels of these by-products, called trihalomethanes, was much higher in pool water than in tap water.
Dust reaction
They are formed when chlorine comes into contact with "organic material" such as dust, sweat or skin.
Chloroform, the most common of these trihalomethanes - and classed as a potential cancer-causing agent - was measured at more than 20 times the level found in tapwater.
The medical benefits of swimming far outweigh any problems caused by chemicals.
Ralph Riley, National Pool Water Treatment Advisory Group
Separate studies have also linked trihalomethanes to miscarriage and foetal malformations.
The researchers, from Imperial College of Science and Technology in London, said earlier studies suggested that uptake of such chemicals could be as much as 141 times greater in a one hour swim as in a 10 minute shower.
Swimmers could be absorbing the chemicals through the skin, inhaling them as they evaporated, or swallowing water.
However, the study did not make any direct link between swimming and health problems in either pregnant women or their unborn children.
Safety pledge
Nevertheless, other experts moved swiftly to reaffirm the safety of swimming.
Ralph Riley, the chairman of the National Pool Water Treatment Advisory Group, said that the chemicals were needed to protect swimmers from infections - and that techniques had been refined over past decades.
He said: "The medical benefits of swimming far outweigh any problems caused by chemicals.
"I don't think it's healthy at all, what these researchers are doing.
"Of course it's to be expected that the levels of these chemicals is higher in pool water than tap water.
It does highlight an area of potential risk to pregnant women and offers a simple solution
Belinda Phipps, National Childbirth Trust
"All the medical experts who have been looking at this say that these levels are safe."
Belinda Phipps, from the National Childbirth Trust, supported the call for reducing the chlorine content of swimming pool water.
"For a vast number of pregnant women in the UK, swimming and aqua exercise programs are a very enjoyable and beneficial part of their pregnancy.
"As such it is critically important to stress that this paper does not attempt to link swimming in indoor pools to miscarriage or birth defects.
"It does, however, highlight an area of potential risk to pregnant women and offers a simple solution to limit chemical levels in swimming pool water by reducing the amount of chlorine used - a measure which the NCT would strongly support."
She added: "All too often in this kind of situation, it is the mother that is made to feel guilty and change her practices.
"The burden of responsibility here lies with appropriate regulatory bodies and not with pregnant women to restrict their habits and lifestyle because of preventable and unnecessary factors such as this."
Changing the water and air in swimming pools more regularly could help
People working in indoor swimming pools could be at risk of developing asthma, researchers suggest.
A study by Birmingham doctors suggests chemicals called chloramines could cause occupational asthma.
The paper, published in the European Respiratory Journal (ERJ), suggests regular swimmers could also be at risk.
It concentrates on just three cases, but the researchers, from Birmingham's Heartlands Hospital, said it opened the door for other studies in the area.
There's nothing in this report to show that asthma has been caused by swimming pools
Ralph Riley, National Pool Water Treatment Advisory Group
Chloramines are produced when chlorine reacts with polluting proteins from swimmers that enter the water from swimmers' bodies from sweat and urine - they cause the characteristic smell of pools.
Chlorine-based chemicals are used to ensure the water is disinfected so infections cannot be passed between swimmers.
The researchers say the amount of chloramines present in the air depends on factors such as swimmers' personal hygiene and the how often the water is changed.
Although there are various kinds of the chemical, nitrogen trichloride is the most common, and the kind the researchers believe causes asthma in indoor swimming pools.
Asthma and work link
The team monitored two lifeguards and a swimming teacher who worked at different pools.
All three had worked in swimming pools for some years before developing asthmatic symptoms.
However, all had begun to suffer cough and wheezing symptoms at work which improved when they were on holiday.
The three were asked to measure their peak expiratory flow (PEF), the maximum volume of air that they were able to force out of their lungs in a second, every two hours for two weeks.
Tests were also carried out using nitrogen trichloride.
In two of the three cases, the researchers found a significant relation between the subjects' asthma and their work.
In the third case, the person was not able to carry out the PEF checks in full because they suffered from wheezing within half an hour of arriving at the pool and had to use an inhaler.
In all three, the nitrogen trichloride tests produced an immediate asthmatic reaction.
None had a reaction to chlorine itself.
Chlorine an 'irritant'
Dr Sherwood Burge, who led the researchers told BBC News Online: "If you have asthma, which is worse when you go swimming, it could be linked to the water in the pool."
He added: "This shows that air in swimming pools is a possible cause of asthma."
Dr Burge said further studies needed to be done, looking at people who worked in swimming pools.
The researchers say their findings should not result in "extreme measures" such as preventing children swimming.
But they suggest disinfectants used in pools should be more carefully chosen and that air and water should be replaced as often as possible.
Professor Benoit Nemery, of the Department of Occupational Medicine of Leuven Hospital, writing in the ERJ, said the Birmingham study was significant, despite its size: "It serves as evidence that asthma caused by indoor swimming pools could be an occupational disease and there is reason to believe that cases are more common than they might seem."
Ralph Riley, head of the National Pool Water Treatment Advisory Group said: "We have known for a long time that chloramines can trigger, rather than cause asthma. There's nothing in this report to show that asthma has been caused by swimming pools."
He said water was constantly being cleaned, and that air was also changed four to six times per hour.
Mr Riley added the industry was constantly looking at ways of reducing the levels of chloramines whilst retaining the protection against infection in the water.
A spokeswoman for the National Asthma Campaign said: "We know that chlorine is an irritant and can trigger asthma but there is not enough evidence to state conclusively that it can cause asthma.
"This is an interesting study but more research is needed to prove there is a possible causal relationship."
Chlorination Research
BLOOD AND BREATH ANALYSES AS BIOLOGICAL INDICATORS OF EXPOSURE TO TRIHALOMETHANES IN INDOOR SWIMMING POOLS Aggazzotti, G., Fantuzzi, G., Righi, E., & Predieri, G. (1998)
Science of the Total Environment, 217, 155-163.
CHLORINE PRODUCT ABSORPTION IN SWIMMERS IS GREATEST VIA THE SKIN Lindstrom, A.B., Pleil, J.D., & Berkoff, D.C. (1997).
Alveolar breath sampling and analysis to assess trihalomethane exposures during competitive swimming training.
Environmental Health Perspectives, 105(6), 636-642
EXERCISING INCREASES THE TOXICITY OF A "SAFE" CHLORINATED POOL ATMOSPHERE Drobnic, F., Freixa, A., Casan, P., Sanchis, J., & Guardino, X. (1996).
Assessment of chlorine exposure in swimmers during training. Medicine and Science in Sports and Exercise, 28(2), 271-274.
AMOUNT OF EXERCISE IS RELATED TO CHLORINE-RELATED CONCENTRATIONS IN THE BODY Cammann, K., & Hubner, K. (1995).
Trihalomethane concentrations in swimmers' and bath attendants' blood and urine after swimming or working in indoor swimming pools.
Archives of Environmental Health, 50(1), 61-65
YOUNG SWIMMERS AT GREATEST HEALTH RISK IN CHLORINATED INDOOR POOLS Aiking, H., van Acker, M.B., Scholten, R.J., Feenstra, J.F., & Valkenburg, H.A. (1994).
Swimming pool chlorination: a health hazard?
Toxicology Letters, 72(1-3), 375-380.
CHLORINATOR TABLETS POSE HEALTH RISKS Wood, B.R., Colombo, J.L., Benson, B.E. (1987).
Chlorine inhalation toxicity from vapours generated by swimming pool chlorinator tablets.
Pediatrics, 79(3), 427-430.
DENTAL ENAMEL EROSION INCREASED IN COMPETITIVE SWIMMERS IN CHLORINATED POOLS Centerwall, B.S., Armstrong, C.W., Funkhouser, L.S., & Elzay, R.P. (1986).
Erosion of dental enamel among competitive swimmers at a gas-chlorinated swimming pool.
American Journal of Epidemiology, 123(4), 641-647.
BRONCHOSPASM IN COMPETITIVE SWIMMERS Reuters Health, March 21, 2001.
A study presented [03/20/2001] in New Orleans at the 57th Annual Meeting of the American Academy of Allergy, Asthma and Immunology, strongly suggested that swimming pool environments adversely affect the lung function of competitive swimmers.
ADDITIONAL REFERENCES
1. Beech, J.A., Diaz, R., Ordaz, C., & Palomeque, B. (1980).
Nitrates, chlorates and trihalomethanes in swimming pool water.
American Journal of Public Health, 70(1), 79-82.
2. Mustchin, C.P., & Pickering, C.A. (1979).
"Coughing water": bronchial hyper-reactivity induced by swimming in a chlorinated pool.
Thorax, 34(5), 682-683.
3. Decker, W.J., & Koch, H.F. (1978).
Chlorine poisoning at the swimming pool: an overlooked hazard.
Clinical Toxicology, 13(3), 377-381.
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