ABSTRACT
Recreational waters are routes of transmission for most water-related illnesses. In this study, the water quality of five selected swimming pools (SP) was examined after disinfection prior to bathing and after bathing by swimmers. SP sampling was carried out weekly for 4 weeks between August and September in Makurdi, Nigeria. Bacterial loads and physicochemical parameters were determined using standard and standard analytical methods, respectively. Most of the physicochemical parameters analyzed were within recommended limit except for residual chlorine, turbidity, dissolved oxygen and total dissolved solids exceeding the permissible limit in some SPs before and after bath. Total heterotrophic count before bath ranged from 2.1 × 107 to 10.9 × 107 cfu/ml and 4.2 × 107 to 17.6 × 107 cfu/ml after bath. Some SPs revealed Salmonella-Shigella spp. contamination before and after bath. Total coliforms (TC) ranged from 0-27 MPN/100 ml and 0-43 MPN/100 ml before and after bath respectively, while faecal coliforms (FC) ranged from 0-9 MPN/100 ml before bath and 0-21 MPN/100 ml after bath. Two of the studied SPs significantly increase in TC (150 and 86%) and FC (105 and 22%) after bath. The results suggest that the possible routes for pools contamination include source of water, inadequate disinfection process, faecal discharge and bather density.
Key words: Swimming pool, bacterial count, bath; physicochemical, standards, Makurdi, coliforms.
Clean water still is a growing problem in the world today; and most communities lack access to portable water and some, if available, do not meet water quality standards for all types of drinking and recreational water. Recreational waters such as swimming pools are artificially formed water bodies for human recreational bathing purposes with or without biological, chemical or other water treatments (Casanovas-Massana and Blanch, 2013). They may be domestic (private), semi-public (for example hotel, school, health club, housing complex, cruise ship) or public (for example municipal) (World Health organization; WHO, 2005). More so, the pools
may be located outside (outdoor) or inside (indoor) or both. Pool water are usually supplied with fresh (surface or ground), marine or thermal water (that is, from natural hot springs) (WHO, 2005). Most often, the type, design and use of pools by bathers may predispose the user to certain health hazards, including pathogenic microorganisms.
The demand of hotels in every community of the world is increasing, especially in fast growing region and tourist attracted areas like river Benue in Northern Nigeria. This has resulted to large increase in hotel business in most part of the metropolis, and still the numbers are not commensurate with the populations.
In this part of the country, water demand remains a serious issue yearly especially during the peak of the dry season, hence most water is supplied by water distribution tankers either filled up directly from a water distribution board, river Benue or any available water source. This water shortage has led pool owners/ managers to evacuate pool water for a long period after severally used by bathers.
Such unhygienic pools could likely harbour potentially accumulated harmful infective dose of microorganisms and organic matters. Meanwhile, for example, most outdoor pools (like those built in hostels) may be subject to higher bather-loads relative to the volume of water (WHO, 2006) and this could be a reservoir for difficult-to-treat pathogens especially the gastrointestinal tract infection. These associated microorganisms in water bodies are detected using specific microbes known as “Indicator organisms” which are used as principal water quality index. The indicator microorganisms used for comprehensive monitoring, evaluating and regulating pool water bodies and similar environments for microbial contamination include heterotrophic bacteria, faecal coliform (E. coli), total coliform (most members of the Enterobacteriaceae), Pseudomonas aeruginosa and Staphylococcus aureus (WHO, 2003; Eaton and Franson, 2005; Yedeme et al., 2017). Microorganisms can be found in swimming pools and similar recreational environment even though measures are put in place to ensure the biosafety and good hygiene quality of the swimming pool water.
Pathogenic organisms and environmental contaminants consistently enter pools directly or indirectly through contaminated air, soil, dust, rain water, sewage, human or animal excrement (especially from birds) (WHO, 2006). Additionally, disease-causing microbes could enter pools through contaminated body fluids such as saliva, blood, urine, vomit, hair, release of respiratory, digestive, genital and other harmful bacteria from the skin by bathers (WHO, 2006; Karami et al., 2015). More often, swimmers may accidentally ingest these non-faecal human materials into pool water.
Generally, pools are disinfected with chlorine, chloramines, ozone, and UV irradiation to reduce health hazard of bathers as well as deactivate potential pathogenic organisms. This disinfection process determines to a large extent the microbiological safety and quality of any pool water. However, high concentration of this disinfecting agent could lead to toxic effects on bathers (Martinez and Long, 1995; Bernard et al., 2003). Apart from these disinfection compounds, other exogenous disinfectants and human inputs such as urine, sweat, hair and human care products (soap residues, cosmetics, suntan oil etc) are released into pool by bathers (WHO, 2006; Chowdhury et al., 2014). This may largely contribute to poor quality of pool water as well poses health threats to bathers resulting from the formation of highly toxic disinfection by-products (DBPS) which include chloramines, trihalomethanes (THMs) and haloacetic acids (HAAs) formed when disinfectants (such as chlorine etc) reacts with these exogenous chemicals and materials (Chowdhury et al., 2014).
Previous researches have reported that microbiological evaluation has, for many years, been the most significant method for sanitary and quality control of swimming pools (Papadopoulou et al., 2008; Onajobi et al., 2013; Karami et al., 2015). For effective quality control, a test for indicator bacteria is usually of primary importance (Itah and Ekpombok, 2004). Additionally, in some part of Nigeria, where water supply is adequate similar studies have been carried out to assess the microbial and chemical quality of pools (Agbagwa and Young-Harry, 2012; Ayandele et al., 2015; Itah and Ekpombok, 2004); however little information is available on the health risk associated with swimming pools especially in the Northern part of the country where water supply is scare and inadequate for pool users, high density due to the terrain and extreme temperature experienced in most part of the season, thus could result to microbial proliferation in water.
Report from the literatures showed that there is no published work on pool water quality (physical, chemical and bacterial) in Makurdi, Nigeria. Therefore, this study was undertaken to evaluate the physicochemical properties and the bacterial loads of some selected swimming pools due to the large populace visiting them; assess and establish the possible sources of pool contamination, and their compliance to World Health organization (WHO) standards for swimming pools.
Sample collection and processing
All studied swimming pools are made of glazed tile with different shapes (rectangular, circular and oval) and their sizes ranged from 500 to 1500 m2. Water pools were disinfected with chlorine once a week if bathers’ density is low and twice weekly when bather’s density is high, however water was not evacuated regularly and replace with fresh water due to the cost of water supply to pools resulting from water scarcity. These swimming pools were chosen based on the frequency of swimmers visiting them. The average number of bathers per day was 90. During late raining season and early dry season (August - September), water samples from 5 randomly selected swimming pools (outdoor pools) in Makurdi metropolis of Benue state, Nigeria were collected weekly for a period of four weeks (two samples between Monday and Friday and two samples during the weekend) and totally 80 pool samples (16 samples from each pool). All pool water samples were collected by 6.45 am in the morning before bathing and 8.00 pm in the evening after bathing from surface (0.1 m) and 0.5 m water depth and mix together to form representative pool samples. Water samples were collected aseptically with reference to WHO sampling techniques (WHO, 2006, 2008). 2000 ml bottles were disinfected with concentrated acetone (allowed to volatilize for at least 2 h in a fumehood), rinsed off with distilled water and aseptically filled up with water samples from the five randomly selected pools. The water samples were collected before and after bathing by swimmers and were appropriately labeled A-E. 4 ml of 10% sodium thiosulphate solution was added to the water to neutralize any free chlorine residue in the water sample to prevent further disinfection effects on the microbial population. After collection, pool samples were transferred immediately to the laboratory and refrigerated at 4°C for bacteriological and physicochemical analyses. Water samples were analyzed soon after collection (before and after bath). Parameters such as temperature and pH values were taken at the site of sample collection.
Pool Locations and Depth; SW1: Flow through pool 9 ft at its deepest point; SW2: Fill and draw pool 8 ft at its deepest point; SW3: Flow through pool 9 ft at its deepest point; SW4: Fill and draw pool 6 ft at its deepest point; SW5: Fill and draw pool 7ft at its deepest point.
Physicochemical analysis
The physico-chemical parameters were measured using standard analytical procedures (American Public Health Association, APHA, 1998; Association of Official Analytical Chemists, AOAC, 2000). The water quality parameters examined included temperature and total dissolved solids (TDS) (measured using Garasa 2-in-1 water quality meter); pH, electrical conductivity (EC), salinity and dissolved oxygen (DO) were measured by HQ30D single channel meter (HACH), while turbidity was measured by turbidity meter, TB250 WL. Others include biochemical oxygen demand (BOD) measured using automated BOD analyzer (BD 600); chemical oxygen demand (COD) using portable COD colorimeter, MD200; and residual chlorine (RC) using Halosense chlorine analyzer. All samples were analyzed before and after bathing by swimmers.
Enumeration of total heterotrophic bacteria
The total heterotrophic bacterial count was carried out on pool water samples using the spread-plate method (Ibe and Okplenye, 2005) on plate count agar (Oxoid microbiological media, UK). A ten-fold serial dilution of each water sample was prepared aseptically in sterile physiological saline up to 10-6 and 0.1 ml aliquot of each dilution was plated on plate count agar plates (in triplicate). The inoculated plates were incubated at 37°C for 24 h. under aerobic conditions and cultured plates containing 30 to 300 colonies were counted. The mean number of viable bacteria present in each sample were expressed as colony-forming units per millimeter (cfu/ml) of pool water and calculated as follows:
CFU/ml= Average No. of colonies on culture plates x 1/dilution factor x 1/volume used (in ml).
Salmonella and Shigella species counts
The spread plate method (Ibe and Okplenye, 2005) was also employed for the enumeration of Salmonella and Shigella species using Salmonella/Shigella agar (SSA) (Fisher scientific, UK) for the different pool water samples. Ten-fold serial dilution of each water sample was prepared aseptically in sterile physiological saline up to 10-3 and 0.1 ml aliquot of each dilution was plated on SSA plates in triplicate. The inoculated plates were incubated at 37°C for 24 h and cultured plates containing 30 to 300 colonies were counted and colonies were expressed as colony-forming units per millimeter (cfu/ml) of pool water.
Enumeration of total coliforms/faecal coliforms
The 5–tube multiple tube fermentation method (also known as the Most Probable Number (MPN) technique) containing MacConkey broth (Fisher scientific, UK) was used to estimate total and faecal coliforms (Ibe and Okplenye, 2005; APHA, 2005). The fecal coliforms (E. coli) were incubated at 44 ± 0.5°C for 24–48 h while the total coliforms were incubated at 37°C for 24–48 h. A confirmatory test on positive tubes from the MPN procedures were subcultured on Levine’s eosin methylene blue (EMB) agar plates using the streak plate method in duplicate and incubated at 37°C for 24 h. Estimation of coliforms (MPN/100 ml) was based on MPN table.
Statistical analyses
The results were analyzed and compared using analysis of variance (ANOVA), while post-hoc test (tukey HSD) was used to determine significant differences between means of pool samples collected before and after bath. Data were presented as mean ± standard error (SE) and p < 0.05 or p > 0.05. Microbial data for pools is presented in graphs.
Physicochemical variations in pool samples
The results of the physical and chemical properties of the studied swimming pools prior to bath and after bathing are represented in Table 1. Generally, the studied swimming pools were within the recommended range for temperature, pH, EC, BOD, and COD before and after bath for all water samples analyzed as stipulated by WHO. More so, there are no significant differences observed before and after bath for pH and temperature. Results of RC concentrations in pools before bath were higher in all sampled pools compared to samples collected after bath (p < 0.05). EC increased in water samples collected from 80% pools after bath (p < 0.05), but the values were within the stipulated WHO limit for EC in recreational water. Considering another parameter such as turbidity, 80% of all the sampled pools revealed higher values than the recommended standard of <1 NTU by WHO before and after bath with exception of SW4 with turbidity values of 0.82 to 0.87, NTU respectively. Notably, one of the pools (SW3) indicated higher turbidity compared to other pools before and after bath. The study revealed that 85% of all studied swimming pools before and after bath exceeded the recommended standard for dissolved oxygen by WHO. Two swimming pools (SW3 and SW4) had the highest values of DO after bath while the least values were recorded for SW2 and SW5 respectively. All pools sampled were within the minimum WHO recommended limit for COD and BOD before and after bath, however statistically lower value was observed SW2 for both properties before bath as compared to other sampled pools. Moreover, 40% of pools sampled revealed high TDS before and after bath compared to WHO recommended limit. Two pools (SW3 and SW4) recorded significantly higher values of TDS before and after bath in comparison to other pools and were also above the recommended limit stipulated by WHO for recreational water.
Enumeration of bacteria in pool samples
The results of bacterial counts for the 5 selected swimming pools prior to and after bath are presented in Figure 1 (A – E). Total culturable heterotrophic bacterial count ranged from 2.1 × 107 to 10.9 × 107 cfu/ml and 6.1 × 107 to 22.7 × 107 cfu/ml with average values of 4.2 × 107 cfu/ml and 17.6 × 107 cfu/ml, respectively. SW4 showed a significantly higher heterotrophic bacterial count after bath, while bacterial colonies were not detected in SW2 before bath, however after bath, there was an observed high heterotrophic bacterial count in SW2. Data showed that all sampled pools after bath showed significantly higher heterotrophic bacterial counts than before bath. The total heterotrophic bacterial counts of all investigated pools before and after bath were much higher than the WHO limit of ≤ 2 ×102 cfu/ml for pool water.
The concentrations of Salmonella-Shigella species count recorded for the swimming pools sampled before and after bath ranged from 0.0 × 103 - 3.0 × 103 cfu/ml and 0.0 × 103 - 17.0 × 103cfu/ml for Salmonella spp. respectively, while Shigella spp. ranged from 4.9 x 103 to 7.8 × 103 cfu/ml and 5 × 103 to 11 × 103 cfu/ml respectively as shown in the figure (B and C). Two sampled pools revealed significantly higher Salmonella counts before bath (SW3 and 4) and after bath (SW4 and 5); however, no detectable Salmonella colonies were observed for SW1, 2 and 5 before bath. But this was not the trend after bath as significantly high colonies were cultured from sampled collected from SW5 after bath. For Shigella spp. detected in pools, two pools (SW3 and SW4) showed higher CFUs than other pools before and after bath (p < 0.05); with no detectable Shigella colonies in other pool samples during the sampling period. Generally, two out of five pools showed presence of Salmonella-Shigella species contamination before and after bath by swimmers.
The MPN number per 100ml of water sampled for total and faecal coliforms in the swimming pools before and after bath are presented in Figure 1 (E and F). The MPN for TC ranged from 0 – 27 MPN/100 ml before bathing and 0 – 43 MPN/100 ml after bath, while that of FC ranged from 0 – 9 MPN/100 ml and 0 – 21 MPN/100 ml before and after bath respectively. In comparison to other pools, two pools (SW3 and SW4) after bath showed significant increase of 150% and 86% for TC and 105 and 22% for FC respectively. At the same time, only one sampled pool had 0 CFU/ml colonies before and after bath for TC, whereas FCs were not detected in two pool samples after bath but this pattern changed in one pool after bathing by swimmers with 6 MPN per 100 ml of pool water sampled. In general, 80% of pools recorded TC counts and 60% for FC counts respectively, with numbers exceeding the WHO standard for recreational waters (≤1/100 ml for TC and 0/100 ml for FC) before and after bath.
There is potentially high health risk of contamination in these studied pools and most did not meet the WHO standards for physicochemical and microbial quality for swimming pools. However, only a few pools comply with WHO permissible limits for recreational water. Water supply, bather density, disinfection processes and other environmental contaminants indicate possible routes of contamination. The pools could represent potential sources and route of transmission of disease-causing organisms if not monitored and regulated. And this could have negative health impact on pool users, especially the young, elderly and immunocompromised or suppressed swimmers. Therefore, it is pertinent for regulatory bodies in Nigeria, carry out periodic checks on the risk-assessment on swimming pools through water quality (that is, source of water supply to pools), frequent environmental sanitation around pools, regular swimmer’s education before entering pools and regular evacuation of water after bathing by swimmers. Specifically, stringent measures should be stipulated to ensuring that pool operators adhere to this information to reduce the public health risk.
The authors have not declared any conflict of interests.
The authors specially thank the managers of swimming pools in Makurdi, Nigeria for the pool water samples collection and also thank the Laboratory staff and technicians of the Department of Biological Sciences, University of Agriculture, Makurdi for providing the enabling environment and facilities for this research work. This research was partially funded/assisted by Department of Biological Sciences, University of Agriculture, Makurdi Nigeria.
REFERENCES
|
Abd El-Salam MM (2012). Assessment of water quality of some swimming pools: a case study in Alexandria, Egypt. Environmental Monitoring and Assessment 184:7395-7406.
Crossref
|
|
|
|
Agbagwa OE, Young -Harry WM (2012). Health implications of some public swimming pools located in Port Harcourt, Nigeria. Public Health Research 2:190-196.
Crossref
|
|
|
|
|
Al-Khatib I, Salah S (2003). Bacteriological and chemical quality of swimming pools water in developing countries: A case study in the West Bank of Palestine. International Journal of Environmental Health Research 13:17-22.
Crossref
|
|
|
|
|
American Public Health Association (APHA), American Water Works Association (AWWF), Water Environment Federation (WWF) (1998). Standard methods for the examination of water and wastewater, 20th edn.; Eaton AD, Clesceri LS, Greenberg AE, Franson MAH, eds. Washington, DC, USA
|
|
|
|
|
American Public Health Association (APHA), American Water Works Association (AWWF) (2005). Standard methods for the examination of water and wastewater, 21th edn.; Eaton, AD, Clesceri LS, Eugene WS, Greenberg AE, Franson MAH, eds. Washington, DC, USA.
|
|
|
|
|
Association of Official Analytical Chemists (AOAC) (2000). Official methods of analysis, 17th edn, Vol. 1. Association of Official Analytical Chemists Inc., Maryland, USA. ISBN: 0935584676 9780935584677.
|
|
|
|
|
Ayandele AA, Adebayo EA, Oladipo EK (2015). Assessment of microbiological quality of outdoor swimming pools in Ilorin, Kwara State. Journal Environmental Science, Toxicology and Food Technology 9:25-30.
|
|
|
|
|
Bello OO, Mabekoje OO, Egberongbe HO, Bello TK (2012). Microbial qualities of swimming pools in Lagos, Nigeria. International Journal of Applied Science and Technology 2:9-96.
|
|
|
|
|
Bernard AC, Michel OS, Buchet JP, Hermans CG, Dumont XR, Doyle IJ (2003). Lung hyper-permeability and asthma prevalence in schoolchildren: unexpected associations with the attendance at chlorinated swimming pools. Occupational and Environmental Medicine 60:385-394.
Crossref
|
|
|
|
|
Casanovas-Massana A, Blanch AR (2013). Characterization of microbial populations associated with natural swimming pools. International Journal of Hygiene and Environmental Health 216:132-137.
Crossref
|
|
|
|
|
Castor ML, Beach M (2004). Prevention of recreational water illnesses: Is chlorination enough to ensure healthy swimming? Infectious Disease in Children 17:1-3.
|
|
|
|
|
Chowdhury S, Alhooshani K, Karanfil T (2014). Disinfection byproducts in swimming pool: Occurrences, implications and future needs: A review. Water Research 53:68-109.
Crossref
|
|
|
|
|
Craun G, Calderon R, Craun M (2005). Outbreaks associated with recreational water in the United States. International Journal of Environmental Health Research 15:243-262.
Crossref
|
|
|
|
|
de-Bashan LE, Bashan Y (2010). Immobilized microalgae for removing pollutants: review of practical aspects. Bioresource Technology 101: 611-1627.
Crossref
|
|
|
|
|
Eaton AD, Franson MA (2005). Standard methods for the examination of water and wastewater (21st ed.). American Public Health Association. 1600 pp. ISBN 978-0-87553-047-5.
|
|
|
|
|
Fleisher JM, Kay D, Salmon RL, Jones F, Wyer MD, Godfree AF (1996). Marine waters contaminated with domestic sewage: nonenteric illness associated with bather exposure in the United Kingdom. American Journal Public Health 86:1228-1234.
Crossref
|
|
|
|
|
Hilles AH, Sarsour A, Ramlawi A, Abed Y (2014). Assessment of sanitary conditions in the main swimming pools in Gaza strip (2010-2013): Palestine. International Journal of Scientific Research in Environmental Sciences 2:261-268.
Crossref
|
|
|
|
|
Ibe SN, Okplenye JI (2005). Bacteriological analysis of borehole water in Uli, Nigeria. African Journal Applied Zoology and Environmental Biology 7:116-119.
Crossref
|
|
|
|
|
Itah AY, Ekpombok MU (2004). Pollution status of swimming pools in south-south zone of south-eastern Nigeria using microbiological and physicochemical indices. Southeast Asian Journal of Public Health 35:488-493.
|
|
|
|
|
Karami A, Mahvi AH, Sharafi K, Khosravi T, Moradi M (2015). Comparing and evaluating microbial and physicochemical parameters of water quality in men's and women's public swimming pools in Kermanshah, Iran: A case study. International Journal Environmental Health and Engineering 4:24.
|
|
|
|
|
Leoni E, Legnani PP, Bucci Sabattini MA, Righi F (2001). Prevalence of Legionella spp. in swimming pool environment. Water Research 35: 3749-3753.
Crossref
|
|
|
|
|
Martinez TT, Long C (1995). Explosion risk from swimming pool chlorinators and review of chlorine toxicity. Clinical Toxicology 33:349-354.
Crossref
|
|
|
|
|
Martins MT, Sato MIZ, Alves MN, Stoppe NC, Prado VM, Sanchez PS (1995). Assessment of microbiological quality for swimming pools in South America. Water Research 29:2417-2420.
Crossref
|
|
|
|
|
Nnaji CC, Agina I, Iloanya I (2011). The ineffectiveness of manual treatment of swimming pools. Journal of Applied Science and Environmental Management 15:517-522. ISSN: 1119-8362.
|
|
|
|
|
Onajobi IB, Okerentugba PO, Okonko IO (2013). Physicochemical and bacteriological studies of selected swimming pool water in Ilorin metropolis, Kwara State, Nigeria. Stem cell 4:10-16.
|
|
|
|
|
Papadopoulou C, Economou V, Sakkas H, Gousia P, Giannakopoulos X, Dontorou C, Filioussis G, Gessouli H, Karanis P, Leveidiotou S (2008). Microbiological quality of indoor and outdoor swimming pools in Greece: investigation of the antibiotic resistance of the bacterial isolates. International Journal of Hygiene and Environmental Health 211:385-397.
Crossref
|
|
|
|
|
Rabi A, Khader Y, Alkafajei A, Aqoulah AA (2008). Sanitary conditions of public swimming pools in Amman, Jordan. International Journal of Environmental Research and Public Health 5:152-157.
Crossref
|
|
|
|
|
Saba CKS, Tekpor SK (2015). Water quality assessment of swimming pools and risk of spreading infections in Ghana. Research Journal Microbiology 10:14-23.
Crossref
|
|
|
|
|
Schwartz J, Levin R, Goldstein R (2000). Drinking water turbidity and gastrointestinal illness in the elderly of Philadelpia. Journal of Epidemiology and Community Health 54:45-51.
Crossref
|
|
|
|
|
Shittu OB, Olaitan JO, Amusa TS (2008). Physicochemical and bacteriological analyses of water used in drinking and swimming purposes in Abeokuta, Nigeria. African Journal of Biomedical Research 11:285-290.
|
|
|
|
|
Sinitsyna O, Zadiran A, Artemova T, Gipp E, Zagai nova A, Butorina N (2012). Evaluation of the informativity of sanitary-epidemiological safety indicators of swimming pools. Gigiena I Sanitaria 5: 84-87. PMID: 23243732
|
|
|
|
|
World Health Organization (WHO) (2003). Guidelines for safe recreational-water environments: coastal and fresh-waters. 1:2-219.
View
|
|
|
|
|
World Health Organization (WHO) (2005). Guidelines for safe recreational water environments. Swimming pools, spa and similar environments. 3rd ed. Vol. 2: recommendations. WHO press, Geneva, Switzerland. Available online:
View (accessed on 10 August 2017).
|
|
|
|
|
World Health Organization (WHO) (2006). Guidelines for safe recreational water environments. Swimming pools and similar environments. 3rd ed. Vol. 1: recommendations. WHO press, Geneva, Switzerland. pp. 3-273.
View
|
|
|
|
|
World Health Organization (WHO) (2008). Guidelines for drinking water quality. Incorporating the first and second addenda (3rd ed.). World Health Organization (WHO) Press Geneva. Switzerland.
View
|
|
|
|
|
Yedeme K, Legese MH, Gonfa A, Girma S (2017). Assessment of physicochemical and microbiological quality of public swimming pools in Addis Ababa, Ethiopia. The Open Microbiology Journal 11:98-104.
Crossref
|
|
