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Water quality of modern water parks.



Water parks are a rapidly growing element of the U.S. tourism industry. These parks offer creatively themed designs from water slides to interactive water activities. As the designs for the attractions become more creative, the possibilities of injury or infections to the users become multiplied (see photo on page 15, top).

The public health responsibility for regulating the operation and design of water park facilities involves injury prevention and reduction and control of the spread of waterborne disease. Park designers are challenged to reduce abrasion and impact injuries by cushioning surfaces at pool basins and edges with various pad materials. Often, the padded surfaces are designed within a themed decor to enhance the attractiveness of the park. But these same features that protect against injuries may actually increase the risk of waterborne disease by harboring and distributing bacteria. For example, foam padding in high traffic areas may provide interstitial spaces for opportunistic bacteria to escape pool water disinfectants and potentially infect swimmers.

The Wisconsin Department of Health completed a two-year study of five indoor and five outdoor water parks throughout the state. The study was initiated to survey the sanitary conditions at these parks, in order to update existing regulations to encompass new designs found in modern water parks. This approach was to provide data for regulators to make better-informed judgments for the health and safety of pool patrons and their children.


A comprehensive surveillance of water, materials, and surfaces was sampled and tested quantitatively for of total coliforms, E. coli, E. coli O157, enterococci, staphylococci, heterotrophic bacteria, and Pseudomonas aeruginosa. All samples were analyzed at the Wisconsin State Laboratory of Hygiene and taken during unannounced visits. All locations were sampled at least three times. Three general categories of samples were established: water (pool water samples), submerged (swabs and material samples from below pool water surface), and damp (swabs, materials, or standing water samples from above pool water surface). All water samples were tested on site with DPD FAS titration colorimetric test kit for free chlorine residual, combined chlorine, and pH.

Pool water samples were further subcategorized into three types commonly found in modern water parks: activity pools, plunge pools, and wading pools. Wading pools were further separated into wading pools with or without permanent poured-in-place padded surface. Activity pools are greater than two feet in depth designed primarily for play activity that uses constructed features and devices. Plunge pools are those at the terminal end of waterslides, which carry over 100 gpm of water down a flume. Wading pools, designed for toddlers and small children, do not exceed two feet in depth and may have padded, permanent poured-in-place impact-attenuating surfaces either partially or completely submerged in water (see photo above, bottom).




Pool waters were tested for compliance per state regulations for water quality; 94.5% of the pool water samples were bacteriologically compliant and 88% were compliant with free chlorine residuals for pools as stated in Wisconsin Administrative Code (1 part per million [ppm] for activity and plunge pools, 2 ppm for wading pools) (Wisconsin Administrative Code, 2002). Wading and plunge pools were below the required free chlorine concentration in 12% of the samples, while no activity pool samples were chlorine deficient. Most water parks have automated technology and highly trained staff, which could explain the high compliance compared to other published pool studies that focused on standard pools. The additional design and operational features of water parks require well-trained operators to oversee multiple unique pool basins. In this survey, all employees were certified in pool operation from a national certifying organization.

Theme and Pad Materials

Theme and pad materials used to cushion the impact of a pool slide or other activities were tested, both those submerged in chlorinated water and those considered damp. Without exception, submersion of features and materials in chlorinated pool water reduced the frequency of target organisms (Figure 1). Bacteria isolated from submerged features (e.g., landing pads below the surface) probably survive because porous interiors or surface films offer protection from chlorinated water. The samples located furthest away from pool water--damp samples--contained the highest populations of bacteria. Bacteria found on damp surfaces are also commonly found on people's skin, hair, and nasal cavities and naturally found in the environment. Over 30% of the population are carriers of the bacteria that we found in the materials (Mainous, Hueston, Everett, & Diaz, 2006).


Play Features

Play features were also tested and those designed for young children and babies were found to harbor the most bacteria (see photo above). Due to the incontinent nature of users of these play features, fecal indicators were found frequently (E. coli, 13%; total coliforms, 53%; enterococci, 87%). Skin indicators such as staphylococci were found in up to 80% of the samples. E. coli and enterococci were found in concentrations as high as 1,050 CFUs/100cm2 and 24,192 CFUs/100 [cm.sup.2], respectively (Figure 2). E. coli O157:H7, the bacterial strain that caused an outbreak in a water park in Atlanta, was never detected in pool water or in any location in the parks.

Submerged Landing Pad Compression Studies

Although water samples from pools that contain landing pad materials were shown to contain very low numbers of target organisms, further evaluation was done to determine whether landing on a pad material may discharge target organisms when under the weight of a bather (see photo on page 17, top). To mimic this effect, a sterile 25 kg container was pushed against submerged padding material while pool water was simultaneously collected. The pool water prior to mat compression was relatively free of target bacteria, where only heterotrophic organisms were found (at levels of 257 CFUs/100mL). Water collected during mat compression, however, contained heterotrophs (9,260 CFUs/100mL) as well as S. aureus and S. epidermidis (228 CFUs/100mL and 100 CFUs/100mL, respectively). This suggests the use of landing pads on the bottom of a pool or waterslide potentially releases more bacteria into the pool recirculation system. The mats could offer protection from residual chlorine to these organisms, but it is not known how long they could survive after release.


Permanent Rubber Surface Attenuating Materials

Personal interviews with park owners revealed that injuries in areas with cushioned surfaces are less frequent than in those with the rough exposed aggregate surface of standard pool basins. Both designers and owners requested additional use of these products in other settings, which prompted permanent rubber surface attenuating materials poured directly onto the pool basin to be evaluated. During the duration of our study, materials were found to degrade in chlorine residuals of 3 ppm, and pieces of the material tested positive for all the target bacteria. The water from wading pools with permanent surfacing materials are 10 times more likely to contain P. aeruginosa than those without surfacing materials, and three times more likely to contain S. aureus (Figure 3).

Common Areas

Common areas of the water parks include locker rooms or lounging decks not necessarily associated with bathing. Because bathers commonly come in contact with such areas when entering and exiting pools, some surfaces and standing water were sampled for target organisms. Although pool water samples associated with these areas were free of target organisms (data not shown), bacteria were detected on rubber mat material used on the floor of a locker room, on the deck area itself, and on handrails on stairs to water attractions. Although E. coli were not isolated from the locker room floor samples, all other target organisms were detected with 100% frequency. Additionally, enterococci, heterotrophic bacteria, S. aureus, and S. epidermidis counts exceeded maximum detection limits in 30% to 100% of the trials. E. coli were isolated from a handrail, deck entrance to a wading pool, and water collected from three deck areas not sloped to drain. One sample from a wading pool deck contained 18,420 CFUs/100 mL. Standing water in deck depressions in high-traffic areas would be particularly prone to bacterial proliferation, because the free chlorine titer is depleted as the water drains from bacteria-laden skin and garments (data not shown). These puddles of water may support viability for days in the absence of a thorough sanitation procedure (see photo on page 17, center).




Few of the materials and play features tested provided adequate cleaning procedures, leaving the pool operator to determine by sight what is considered "dirty." If pad materials and play features are used, they should be considered in inspection criteria, because some offer protective environments where opportunistic pathogens such as Pseudomonas and Staphylococcus can thrive. Special care and time should be dedicated to these additional features in the pool area. Manufacturers should provide cleaning and sanitizing recommendations with their products. Proper cleaning procedures must be provided and followed to keep microbes from flourishing in environments lacking a steady stream of chlorine (see photo at right, bottom).

Overall, the parks were found to be operating properly. Readers should be cautious not to overemphasize the presence of these organisms. A study done by Ojima and coauthors (2002), suggests bathrooms and kitchens harbor some of the same microorganisms, and in similar abundance.


Pool water samples contained the fewest number of target organisms, followed by submerged samples of features and pads. The highest rate of positive samples was in features and pads in the damp category. Play features designed for infants and toddles, categorized as damp, were found to be likely vehicles for transference of gastrointestinal bacteria. The array of target organisms isolated from damp features suggests that in the absence of exposure to chlorinated pool water, such features should be sanitized on a routine basis using a combination of chemical and physical methods, preferably as recommended by the manufacturer.




The organisms isolated from submerged features probably survive because of biofilm protection or hindrance to the access to chlorinated water. Free-floating organisms, however, originating either from biofilms or bathers, were apparently controlled by chlorination, and the low incidence of positive pool water samples reflects this.

The benefits of preventing impact injuries by using pad materials are appreciated and no epidemiologic evidence exists linking pad materials to disease transmission. Nevertheless, the frequency of bacteria detected in pools using permanent surface materials has increased compared to pools without the materials. Study results also suggest that using landing pads on the bottom of a pool or waterslide potentially releases more bacteria into the pool recirculation system. If pad materials and play features are used, they should be considered in inspection criteria. Common areas, including decks, should also be evaluated during inspection and daily maintenance.


In an effort to reduce the amount of fecal bacteria transmitted, Wisconsin passed legislation in 2005 requiring diaper-changing stations in all new pools and water parks. This includes both men's and women's restrooms, providing an alternative for baby and small toddler needs in proper locations. This research provided new data that facilitated a science-based reassessment of the Wisconsin Department of Heath's existing swimming pool regulations. The revisions passed in 2007 and were enacted in February 2008. The complete research paper is published in the Journal of Water and Health (Davis, Standridge, & Degnan, in press).

Acknowledgements: This work was supported by the Department of Health and Family Services, Bureau of Environmental Health, in collaboration with the Wisconsin State Laboratory of Hygiene, Archie Degnan, and Jon Standridge. Special thanks to the Wisconsin water park owners and operators and Daryl Matzke, P.E.

Editor's note: Tracynda Davis currently serves as Technical Section Chair of General Environmental Health for NEHA and represents NEHA on the Steering Committee for the Centers for Disease Control and Prevention's (CDC's) Model Aquatic Health Code (MAHC). She is also Vice Chair of the Water Quality Technical Committee for the MAHC.

Americans appear to be visiting our nations' water parks more and more, yet it is probable that health regimens for proper operation have yet to be widely developed and enforced. The following research study serves as a reminder that awareness and good maintenance practices are fundamental to public health in aquatic environments.

This article highlights research Ms. Davis developed and conducted (in conjunction with the Wisconsin State Lab of Hygiene) as program manager of recreational water at the Wisconsin Department of Health and Family Services. This article is designed to raise awareness for environmental health specialists when inspecting water parks. Additionally, the information will help regulators, owners, and operators develop guidelines to improve public health and safety at water parks.

Preliminary research on indoor water parks was originally presented by Davis at NEHA's AEC & Exhibition in Reno in 2003, and her study on outdoor water parks was presented at the AEC in 2004.

Davis holds an M.P.H. from the University of South Florida with a concentration in environmental health. She was named an Emerging Environmental Health Leader by CDC and NEHA in 2004. She was a fellow in the inaugural class of the Environmental Public Health Leadership Institute, organized by CDC. She was nominated for the Balderson Leadership Award by the American Public Health Association for her project entitled, "Creating a Comprehensive Water Attraction Program in Wisconsin."

Davis is currently director of environmental health programs at the National Swimming Pool Foundation[R]. Her primary objective is to coordinate and expand environmental health programs to raise educational standards for operators and inspectors at a national level.

Water Park Inspections Checklist

[] Check for areas not sloped to drain (important during preinspections):

* Locker rooms/restrooms

* Walkways

* Spray grounds

* Decks

[] If puddles of standing water are found during routine inspections, areas should be cleaned with chlorinated water daily.

[] Diaper changing stations should be clean and in good condition.

[] Diaper changing station and restroom signage should be easily visible for patrons.

[] Request that posted signs prohibit diaper changing on pool deck or incorporate this in regulation.

[] Recommend that the operator check the condition of pad materials and play features daily, record condition in a log book, and follow manufacturer's cleaning protocols.

[] Ask operator for cleaning protocols for pad materials and play features used.

[] Make time during inspection to educate pool operators on the importance of following cleaning protocols specified for products used.

[] Encourage operators to educate patrons on how disease can be spread (e.g., provide fact sheets for distribution to patrons addressing fecal accidents or vomiting and requesting parents to notify staff of occurrences).

[] Recommend further education for the public on the importance of showering with soap before using pools, avoiding swimming with diarrhea, and taking other preventative steps to reduce the risk of illness.


Davis, T., Standridge, J., & Degnan, A. (in press). Bacteriological analysis of indoor and outdoor water parks in Wisconsin. Journal of Water and Health. doi: 10.2166/ wh.2009.028

Mainous III, A., Hueston, W., Everett, C., & Diaz, V. (2006). Nasal carriage of Staphylococcus aureus and methicillin-resistant S. aureus in the United States, 2001-2002. Annals of Family Medicine, 4, 132-137.

Ojima, M., Toshima, Y., Koya, E., Ara, K., Kawai, S., & Ueda, N. (2002). Bacterial contamination of Japanese households and related concern about sanitation. International Journal of Environmental Health Research, 12, 41-52.

Wisconsin Administrative Code. Chapter HFS 172. (2002). Safety, maintenance, and operation of public swimming pools. Register No. 557.

The use of third-Party review To reduce Health and Environmental Hazards From surfactants and Cleaning Products In the Janitorial Industry Kazuhiro Okumura

Tracynda Davis, M.P.H.

Corresponding Author: Tracynda Davis, Director, Environmental Health Programs, National Swimming Pool Foundation[R], 4775 Granby Circle, Colorado Springs, CO 80919. E-mail:
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Title Annotation:Guest Commentary
Author:Davis, Tracynda
Publication:Journal of Environmental Health
Geographic Code:1USA
Date:May 1, 2009
Previous Article:2009 Atlanta Georgia Annual Conference.
Next Article:The use of third-party review to reduce health and environmental hazards from surfactants and cleaning products in the janitorial industry.

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