A survey of heterotrophic bacteria and coliforms in the water of old and new distribution networks

Document Type : Original Article

Authors

1 Student Research Committee, Department of Environmental Health Engineering, School of Public Health and Paramedicine, Semnan University of Medical Sciences, Semnan, Iran

2 Department of Environmental Health Engineering, School of Public Health and Paramedicine, Semnan University of Medical Sciences, Semnan, Iran

Abstract

Controlling the microbiological quality of water is important for its uses. Microbiological requirements of drinking water ensure the absence of coliforms, but may indicate the potential presence of other potentially pathogenic microorganisms and viruses of fecal origin. A total of 36 water samples, representing the drinking water of the whole city of Aradan, Semnan, Iran, were randomly collected from the old and new distribution systems of Aradan from December 2014 to June 2015.The hetroterophic plate count (HPC), coliform, residual chlorine, and pH of the samples were measured. Heterotrophic bacteria were measure using R2A and nutrients agar culture media, and the spread plate count method was used to determine HPC. Average concentration of total coliform in the old distribution network ( 13⁄84 100 ml ) was more than the new distribution network ( 9⁄42 100 ml ). The results of studying microbial load in the old and new distribution network showed that there is a significant difference between total coliforms in the two networks (P = 0.002). Moreover, the average concentration of heterotrophic bacteria in the old distribution network (1917.33 number/100 ml) was more than that in the new distribution network (14.57 number/100 ml). There was a significant difference between the average concentration of heterotrophic bacteria in the old and new distribution networks (P = 0.003). The effects of seasons and the age of the water network on coliform bacteria and heterotrophic bacteria were also studied. The concentrations of heterotrophic bacteria, total coliform, and fecal coliforms were higher in the old distribution network in comparison to that in the new distribution network.

Keywords


1. Shabankareh Fard E, Hayati R, Dobaradaran S. Evaluation of physical, chemical and microbial quality of distribution network drinkingwater in Bushehr, Iran. Iran South Med J 2014; 17(6): 1223-35.
2. Miranzadeh MB, Heidari M, Mesdaghinia AR, Younesian M. Survey of microbial quality of drinking water in rural areas of Kashan-Iran in second half of 2008. Pak J Biol Sci 2011; 14(1): 59-63.
3. Hashemi A, Pourhossein T, Dehghanzade R. Analysis of physical and chemical events in Tabriz drinking water. Tabriz University of Medical Sciences. J Chem Environ 2012; 3(10): 5-10.
4. Mokhtari SA, Fazlzadeh Davil M, Dorraji B. Survey of bacteriological quality of the drinking water in rural areas of ardabil city. J Health 2011; 2(1): 66-73.
5. Noorozi R, Zafarzadeh A, Youlizadh T. Survey on microbial quality of drinking water in city maravehtapeh villages and comparison with national and WHO standards. J Environ Health Eng 2013; 1(1):20-9 2013; 1(1): 20-9.
6. Amouei A, Bagher Miranzadeh M, Shahandeh Z, Taheri T, Asgharnia HA, Akbarpour S, et al. A study on the microbial quality of drinking water in rural areas of mazandaran province in north of Iran (2011). J Environ Prot 2012; 3(7): 605-60.
7. Asamoah Sakyi P, Asare R, Anani C, Boakye Dampare S. Nutrient-induced growth of coliform and HPC bacteria in drinking-water pipes. J Environ Prot 2012; 3(6): 508-17.
8. Zazouli M A, Safarpour Ghadi M, Veisi A, Habibkhani P. Bacterial contamination in bottled water and drinking water distribution network in Semnan, 2012. J Mazandaran Univ Med Sci 2013; 22(1): 151-9. [In Persian].
9. Ranjbar D, Dobaradaran S, Tahmasebi R, Ravanipour M, Farahmandnia M, Kazemi T. Check the quality of drinking water bacterial intercity bus in the port of Bushehr in 2012. Proceedings of the 16th National Conference on Environmental Health; 2013 Oct 1-3; Tabriz, Iran. [In Persian].
10. World Health Organization. Heterotrophic plate count measurement in drinking water safety management [Online]. [cited 2002]; Available from: URL: http://www.who.int/water_sanitation_health/dwq/WSH02.10.pdf
11. Mosaferi M, Shakerkhatibi M, Mehri Badloo A. Heterotrophic bacteria in drinking water in Tabriz,
Iran. J Sch Public Health Inst Public Health Res 2011; 8(4): 83-92.
12. Ahmari G, Kalantari S. Survey factors affecting the growth of heterotrophic bacteria in the water distribution network drinking water Arak [Online]. [cited 2010]; Available from: URL: http://www.abfamarkazi.ir/_DouranPortal/documents/tahghighat/hetrotroph_7.pdf. 2016.
13. World Health Organization. Guidelines for drinking-water quality. Geneva, Switzerland: World Health Organization; 2004.
14. Amin R, Ali SS, Anwar Z, Khan Khattak JZ. Microbial Analysis of Drinking Water and Water Distribution System in New Urban Peshawar. Curr Res J Biol Sci 2012; 4(6): 731-7.
15. Hamida A, Javed A, Mohammad NA, Musaddiq I. Bacteriological analysis of drinking water of hand pumps in different schools of District Peshawar (Pakistan). Pak J Food Sci 2006; 16(1-4): 34-8.
16. Nagatani T, Yasuhara K, Murata K, Takeda M, Nakamura T, Fuchigami T, et al. Residual Chlorine Decay Simulation in Water Distribution System. Proceedings of the 7th International Symposium on Water Supply Technology; 2006 Nov 22-24; Yokohama, Japan.
17. Li X, Gu DM, Qi JY, M U, Zhao HB. Modeling of residual chlorine in water distribution system. J Environ Sci (China) 2003; 15(1): 136-44.
18. Hilborn ED, Covert TC, Yakrus MA, Harris SI, Donnelly SF, Rice EW, et al. Persistence of nontuberculous mycobacteria in a drinking water system after addition of filtration treatment. Appl Environ Microbiol 2006; 72(9): 5864-9.
19. Allen MJ, Edberg SC, Reasoner DJ. Heterotrophic plate count bacteria-what is their significance in drinking water? Int J Food Microbiol 2004; 92(3): 265-74.
20. Pavlov D, de Wet CM, Grabow WO, Ehlers MM. Potentially pathogenic features of heterotrophic plate count bacteria isolated from treated and untreated drinking water. Int J Food Microbiol 2004; 92(3): 275-87.