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General Health Issues

Emerging Health Concerns in Indoor Pools & Water Parks

  • October 26, 2010
  • 10 min read
Emerging Health Concerns in Indoor Pools & Water Parks

Water activity – fun and therapeutic
Swimming is an excellent recreational as well as an aerobic activity that can work wonders for the body and the soul. It not only exercises our heart and lungs but also benefits our mind. May it be kicking workouts, water aerobics, pool running, regular swimming, recreational fun for individuals and families in water parts or a water exercise for therapy & rehabilitation; it has always been a refreshing activity for the human body. Regular swimming builds physical endurance, muscle strength and supplements any cardiovascular requirement for the body. Not only that, it is an excellent process to relieve everyday’s stress and practice meditation with the rhythm of our strokes in the water, thus refreshing our soul.
With the advent of science & technology and expansion in infrastructures, indoor swimming pools and recreational facilities like water parks are becoming a preferred choice and destination for individual or family fun activities. These facilities combine relaxation and enchantment of the tropical islands with the wild excitement in indoor water parks with climate controlled temperatures. But even swimming indoors comes with its own sets of concerns.

Swimming pool chloramines
Indoor Swimming pool facility

Concern in indoor water facilities

Swimming pool water contains natural organic matter precursors not only from the tap water itself but also from bathers, including constituents of sweat and urine, skin particles, hair, microorganisms, cosmetics, and other personal care products. The pool water is often treated with Chlorine which is an effective disinfectant, killing algae, mold and bacteria that can cause illnesses. While chlorine, as a disinfectant, is necessary to protect the health of swimmers, bathers and users of pools, spas ,water parks and other indoor facilities but the chemical reaction between chlorine and naturally occurring organic matter in the water form new chemical compounds called disinfection by-products (DBPs). Chlorine bonds with these DBPs to form CHLORAMINES which may include inorganic chloramines,organic chloramines, haloacetonitriles, and other organic compounds, some of which are volatile and known respiratory irritants. The exposure is not only limited to users but also to the employee and staff in the area incl. life guards who are exposed to such DBPs in enclosed spaces for longer durations.

That usual smell of chlorine in the indoor facilities and pools usually is indicative of hygienic water and safe conditions; however such is not the case. Ironically, it is the reverse. That familiar pool smell is due to the presence of chloramines, as they build up in the water and become airborne which is then responsible to cause eye, skin and respiratory irritation and wheezing .There is also evidence that irritant chemicals may contribute to the incidence of asthma in children and adults.

skin rash due to chloramine
Irritant Skin rashes

This problem of chemicals accumulating above the pool, in the air where swimmers are breathing is the newest emerging health concern in the field of indoor recreational water activities and has been confirmed by CDC, Center of Disease Control, in USA. In the recent years, there is recorded evidence that the frequency of waterborne diseases is increasing in treated-water venues such as water parks, spray parks and public swimming pools resulting in record outbreaks of parasite Cryptosporidium (crypto), and the toxic Bacterium E Coli.

What is causing it?

As per American Chemistry Council, when chlorine (Sodium Hypochlorite) is added to the pool water for disinfection, it releases two chemicals to destroy waterborne germs:  hypochlorous acid, HOCl, and hypochlorite ion, OCl-. A measure of the chlorine in these two chemicals is known as “Free Available Chlorine”.  Pool operators manage the Free Available Chlorine level of pool water for the safety of swimmers. Their challenge comes from the fact that Free Available Chlorine is reduced when it reacts with perspiration, oils and urine from swimmers to form chloramines. One way that chloramines are formed in pool water is by the reaction of hypochlorous acid with ammonia.

Ammonia, NH3, is a component of sweat and urine. Its chemical structure is illustrated in the figure at the right. There are three chemical reactions that can occur when hypochlorous acid reacts with ammonia, each involving the replacement of hydrogen ions with chlorine ions.
When one of ammonia’s hydrogen ions is replaced with chlorine, monochloramine is formed:
     HOCl  +  NH3   →   NH2Cl  +  H2O

Replacing one more hydrogen ion with chlorine produces dichloramine,
HOCl  +  NH2Cl   →   NHCl2  +  H2O
Finally, it is possible to replace all three of ammonia’s hydrogen ions with chlorine to form trichloramine, also known as nitrogen trichloride:
HOCl  +  NHCl2   →   NCl3  +  H2O.                                                                       
Dichloramine and especially trichloramine are the chloramines most responsible for pool smell. Chloramines, specifically tri¬chloramine, are suspected as a primary cause of reported irritation symptoms based on exposure monitoring studies. People exposed to trichloramine may experience respiratory symptoms such as cough, chest tightness, wheezing, and eye irritation.       

Another DBP, Endotoxin, which is found in the cell wall of certain bacteria, is released when the bacterial cell breaks down or multiplies. It has been found in various industrial and nonindustri¬al settings associated with bacterial contamination, humidifiers, air con¬ditioners, and other water-associated processes. It can cause airway and al¬veolar inflammation as well as chest tightness, fever, and malaise and acute reduction in lung function.
Water parks can have high numbers of users, including young children, spend¬ing long lengths of time in the water park area, which can be a major contribut¬ing factor to DBP production because they produce sweat and urine. The av¬erage amount of urine, which contains nitrogenous compounds, released into pool waters per bather is 25 to 30 mil¬liliters, and each liter of sweat contains one gram of nitrogen. As more sweat and urine are released into the pool wa¬ter, the nitrogen-containing compounds also increase which can chemically mix with disinfectants to create irritating DBPs in the air.

Poor Ventilation
The buildup of these irritants in the air is partially due to poor ventilation and lack of fresh air flow in the enclosed facilities. The poor movement of fresh air over the pool surface, combined with the use of air recycling devices to control heating costs, leads to poor air exchange. Recyclers remove the moisture from the air, but they do not necessarily take in much fresh air. This may save money on heating, but the health risks to the users and staff associated with the excessive use of these devices outweigh the financial benefits. Without adequate fresh air, the recycled air flowing over the pool becomes saturated with DBPs so that it can no longer absorb or pick up new by-products coming from the pool water. Because recyclers do not remove all of the by-products in the air, they allow the irritants to accumulate and reach unhealthy levels. In addition, if the air is saturated with irritants, new irritants produced in the water will stay in the pool water causing further irritation for swimmers, such as stinging or red eyes.
At times, pool operators may receive complaints from swimmers and pool staff about stinging eyes, nasal irritation, or difficulty breathing after being in the water or breathing the air at indoor aquatic facility. Also, indoor water parks have many splash and spray features that can aerosol¬ize contaminants from the water into the air, where users and employees can inhale them.

What can be done ?
(a)     Use of UV Technology
Good news is that advanced technology can help us eliminate these threats in the indoor aquatic facilities. Ultra Violet (UV) light is very important for indoor pool applications. UV light has the unique ability to decompose chloramines to harmless compounds while also providing additional disinfection power without chemicals.  When UV light systems are installed in the circulating water piping, the water and air quality are improved.  Additionally, operating costs and risks for the facility owners are reduced. It does two purposes. Firstly, it disinfects water and kills bacteria. Secondly, it destroys chloramines and thus improves the air quality in any indoor aquatic facility. UV technology helps to inactivate pathogens, viruses and water borne parasites like Cryptosporidium as well as Chloramines with the help of specific wavelength lamps .While 254-nm is the effective wavelength for germicidal disinfection, chloramines destruction requires 250-385 nm. When correctly applied, chloramines can be reduced drastically by using this technology in the indoor aquatic facilities.

(b)     Training of Employees

The employees and staff must be specifically trained to recognize the signs and symptoms of eye and respiratory irritation, skin rash, and asthma that may be attribut¬ed to DBP exposures. Same should be reported to the management of the facility for immediate appropriate action. Such procedures and trainings will help eliminate or minimize exposure to DBPs and endotoxin and reduce respiratory, skin, and mucous mem¬brane irritation potentially related to these exposures. Sometimes, if the signs and symptoms of such a situation are not located and dealt with in a timely manner, this can become a major life threatening situation in indoor pools, water parks and recreational facilities.

(c)     Improving indoor Air Quality
The problem of poor indoor air quality can be fixed through a combination of preventive measures. One option is to improve the air movement over the pool and increase the air turnover rate in order to reduce irritant levels in the air. If possible, all doors and windows in the pool area should be kept open or fans be used to boost the airflow over the pool surface when many swimmers or users are using the water facility. Same to be done while carrying out super-chlorination. Also, it should be ensured that the air recycling systems are bringing in enough fresh air and proper ventilation is maintained in the facilities at all times. This can be done by making extensive changes in the ventilation system including, adding additional supply diffusers and lowering return air vents closer to deck lev¬el and aerosolizing spray features. This will help in the increase of air handling unit’s volume of airflow. Also ductwork changes can be made to increase air movement to the front and back areas of an aquatic water facility.

(d)     Adopting Good Hygienic practices
It is extremely important for the aquatic water facilities to adopt and implement good hygiene practices for their users before and during the water use. The users including children must take showers before getting in the water .This practice helps remove the organic compounds from their bodies which otherwise could result in an increase in DBPs in the water. It is a good practice to promote regular bathroom use for the kids to reduce the amount of urine in the pool which can help decrease the formation of irritants.
Regarding water quality and air quality inside an indoor aquatic facility, CDC, Center for Disease Control in USA has maintained guidelines to comply with. However, it is always important to be vigilant when we go to an indoor water facility. If something doesn’t look good, smells or feels good, we should always ask questions. For the health of users, staff and employees, it is suggested that all indoor aquatic facilities need UV Technology, good employee training, adequate fresh air exchange and implementation of good hygienic practices for its users. This will help make all pools a healthier and more enjoyable place to play and work.

Article By : Dr. Tarun Batra

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  • Very informative article. I am disappointed though, that the only water treatment remedy listed under “What can be done?” is UV Technology. The other steps mentioned are important in the prevention effort, but one very effective and critical preventative step was left out that should be employed prior to investing in UV. That is effective chlorination, which is accomplished via a feed system capable of staying ahead of a facility’s chlorine demand. When this is in place, DBP’s do not have an opportunity to fully develop due to an incomplete oxidation process. Another term for this is “Continuous Breakpoint Chlorination”.

    The high capacity vacuum induction feed process has proven to be highly effective in the control of disinfection by-products resulting from incomplete oxidation during the treatment of recreational water with sodium hypochlorite. See for more on chloramine prevention.

    • Thank you Robert T. Burrows for your reading and a genuine comment. Your comment itself is equally helpful for our readers.

  • Our special thanks to Dr.Batra for a well-worked out and informative article

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