Analysis of the microbial quality in drinking water distribution networks using the logistic regression model in Dasht-e Azadegan county, an arid region in the southwest of Iran

Document Type: Original Article

Authors

1 Department of Environmental Health Engineering, Behbahan Faculty of Medical Sciences, Behbahan, Iran

2 Department of Environmental Engineering, Islamic Azad University, Ahvaz, Iran

3 Department of Radiology, Behbahan Faculty of Medical Sciences, Behbahan, Iran

4 Student Research Committee, School of medicine, Shiraz University of Medical Sciences, Shiraz, Iran

Abstract

The microbial quality of water plays a key role in community health. The present study aimed to determine the microbial quality of the drinking water distribution networks in the urban and rural areas of Dasht-e Azadegan County, Iran and assess the influential factors in the quality of drinking water.In this descriptive-analytical study, 907 drinking water samples were collected from the urban and rural regions in Dasht-e Azadegan County in 2017. Turbidity, free residual chlorine, pH, total coliforms, and fecal coliforms were measured using the Standard Methods for the Examination of Water and Wastewater, and the results were analyzed using the logistic regression model. The free residual chlorine was within the range of 0-3 mg/L (mean: 0.72 mg/L). The free chlorine residual in 58% of the samples was within the recommended range of the World Health Organization (WHO) for drinking water, and 29% of the samples had higher turbidity than the accepted limit of the WHO (5NTU). In addition, 7.7% and 16% of the samples were infected with fecal and total coliforms, respectively. According to the results of the logistic regression analysis, coliform contamination was most significantly associated with free chlorine residual and turbidity, and reduced free chlorine residual was most effective in coliform contamination.

Keywords


1. Agatemor C, Okolo PO. University of Benin water supply system: Microbiological and physico-chemical assessments. Environmentalist 2007; 27(2): 227-239.

2. Ahmed A, Noonari T, Magsi H, Mahar A. Risk assessment of total and faecal coliform bacteria from drinking water supply of Badin city, Pakistan. J Environ Profes Sri Lanka 2013; 2(1):52-64.

3. Shakya P, Joshi TP, Joshi DR, Bhatta DR. Evaluation of physicochemical and microbiological parameters of drinking water supplied from distribution systems of Kathmandu municipality. Nepal J Sci Technol 2013; 13(2): 179-184.

4. Ahmad S, Ali A, Ullah I, Naz N, Ali A, Ali N. Bacteriological and biochemical evaluation of the spring’s water of district Buner Khyber Pakhtunkhwa Pakistan. Int J Adv Res Technol 2013; 2(7): 452-460.

5. Zazouli MA, 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): 151-159.

6. Mousazadeh R. Chemical and microbiological quality of drinking water in Bandar Abbas. Eur J Exp Biol 2013; 3(4): 254-256.

7. Al-Khatib IA, Arafat HA. Chemical and microbiological quality of desalinated water, groundwater and rain-fed cisterns in the Gaza strip, Palestine. Desalination 2009; 249(3): 1165-1170.

8. Kosamu L, Gama S, Tsakama M, Mughogho B, Tenthani C. Assessment of changes in drinking water quality during distribution: A case study of Area 25 Township in Lilongwe, Malawi. Afr J Environ Sci Technol  2013; 7(5): 153-158.

9. Chowdhury S. Heterotrophic bacteria in drinking water distribution system: A review. Environ Monit Assess 2012; 184(10): 6087-6137.

10. Blokker E, Furnass WR, Machell J, Mounce SR, Schaap PG, Boxall JB. Relating water quality and age in drinking water distribution systems using self-organising maps. Environ 2016; 3(10): 1-17.

11. Mahto B, Goel S. Bacterial survival and regrowth in drinking water systems. J Environ Sci Eng 2008; 50(1): 33-40.

12. Gardner KK, Vogel RM. Predicting ground water nitrate concentration from land use. Groundwater 2005; 43(3): 343-352.

13. Nezhad AB, Emamjomeh MM, Farzadkia M, Jafari AJ, Sayadi M, Talab AHD. Nitrite and nitrate concentrations in the drinking groundwater of Shiraz city, south-central Iran by statistical models. Iran J Public Health 2017; 46(9): 1275-1284.

14. Verhille S. Understanding microbial indicators for drinking water assessment: Interpretation of test results and public health significance. National Collaborating Centre for Environmental Health 2013.Available at : http://www.ncceh.ca/sites/default/files/Microbial_Indicators_Jan_2013_0.pdf

15. Lu W, Zhang X-J. Factors affecting bacterial growth in drinking water distribution system. Biomed Environ Sci 2005; 18(2): 137-140.

16. Tyagi V, Chopra A, Kazmi A, Kumar A. Alternative microbial indicators of faecal pollution: Current perspective. Iran J Environ Health Sci  Eng 2006; 3(3): 205-216.

17. Amanidaz N, Zafarzadeh A, Mahvi AH. The Interaction between heterotrophic bacteria and coliform, fecal coliform, fecal Streptococci bacteria in the water supply networks. Iran J Public Health 2015; 44(12): 1685.

18. Jaleilzadeh A, Ghaesari M, Toosi M, Safari M, Soleimani Z. A survey of heterotrophic bacteria and coliforms in the water of old and new distribution networks. J Adv Environ Health Res 2016; 4(3): 135-141.

19. Prest EI, Hammes F, Van Loosdrecht M, Vrouwenvelder JS. Biological stability of drinking water: controlling factors, methods, and challenges. Front Microbiol 2016; 7( 45):1-24.

20. Thani TS, Symekher SML, Boga H, Oundo J. Isolation and characterization of Escherichia colipathotypes and factors associated with well and boreholes water contamination in Mombasa County. Pan Afr Med J 2016; 23(1).

21. Chaidez C, Soto M, Martinez C, Keswick B. Drinking water microbiological survey of the Northwestern State of Sinaloa, Mexico. J Water Health 2008; 6(1): 125-129.