Swimming pools need chemical treatment to eliminate contaminants and prevent disease. Public pools require continuous monitoring to keep patrons healthy and comfortable when usage peaks in summer months as well as when crowds thin out in the winter. The Centers for Disease Control and Prevention says that the use of proper hygiene also helps keep swimming safe.
Types
The most common chemical used in pool treatment is chlorine. Chlorine is a very reactive element and pool management specialists choose between different forms of chlorine available commercially. In its gaseous form, chlorine is very dangerous. Despite the low cost of using chlorine gas, some municipalities ban it because of the extreme risks associated with its use. Calcium hypochlorite, available in pellets or in a granular powder is cost-effective and safer than the pure chlorine gas. Sodium hypochlorite is a liquid solution, which, like calcium hypochlorite raises pool pH. Trichloroisocyanuric acid, available as solid tablets, lowers pool pH and is more stable than the previous two options. It also costs more.
Bromine is chemically similar to chlorine, but takes longer to break down contaminants and swimmers have more trouble washing it off their bodies. Bromine is also more expensive than chlorine.
Function
Swimming pool chemicals function to disinfect the water from contaminants. According to D.M. Bonnick, BSc, MSc, CChem, MRSC, in "Swimming Pool Disinfection Techniques & Pitfalls," sources of contamination in pool waters include bacteria, viruses and organic compounds from human and animal waste as well as ammonia from urine.
The careful balance of chemicals used also serves to maintain proper pH levels in the pool. According to the Centers for Disease Control and Prevention, correct pool pH levels fall between 7.2 and 7.8. Higher pH inhibits the disinfection capabilities of chlorine, whereas lower levels cause discomfort in humans and corrode pipes.
Effects
The main effects of maintaining a pool with chemicals are clean, safe waters for recreation and fitness. In a secondary effect, the byproducts from the disinfection process cause a strong pungent odor, skin irritation, irritation of mucus membranes and lung irritation.
In "Swimmer" magazine, Mary Pohlman, M.D., assistant professor of clinical medicine at Southern Illinois University School of Medicine and a member of the United States Masters Swimming Sports Medicine Committee, says, that the accumulation of chloramines, such as dichloramine in the water and nitrogen trichloride or trihalomethane in the air, causes symptoms in some swimmers. When contaminant levels rise in the pool, sometimes the available chlorine becomes inadequate to regulate the chloramines byproducts, and side effects multiply.
Geography
Managers usually use chlorine for outside and larger pools, because it is cheaper than bromine and because bromine breaks down in sunlight, according to Dr. Pohlman. Indoor pools sometimes rely on additional ozone treatments to help break down byproducts resulting from disinfection of organic compounds that chlorine cannot destroy. Outdoor pools usually benefit from the breakdown that naturally occurs in the atmosphere.
Considerations
Sensitive swimmers may find the side effects from pool chemicals irritating and sometimes, debilitating. Switching from one indoor facility to a better-ventilated and better-maintained one helps, as does swimming outside whenever possible. Taking antihistamines sometimes helps sinus and nasal irritation says Dr. Pohlman, as does wearing nose clips. Asthma sufferers should explain symptoms to a physician, as these swimmers might need medication.
References
- USMSSwimmer: The Health Swimmer: Readers Ask
- Centers for Disease Control and Prevention: Your Disinfection Team: Chlorine and pH
- Siemens: Swimming Pool Disinfection Techniques & Pitfalls
- North Carolina Department of Environment and Natural Resources: Water Chemistry for Swimming Pools
- USMSSwimmer: The Healthy Swimmer: Coping With Chlorine Reactions
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