daily living, miscarriage, birth defect, pregnancy safety, swimming

Fears Over Swimming Pool Chemicals

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 tapwater 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. 


Separate studies have also linked trihalomethanes to miscarriage and fetal 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. 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. "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 programmes 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."

H Chu and M J Nieuwenhuijsen Occup Environ Med 2002; 59: 243-247
From the BBC News: 4/4/2002