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Bacteriological qualities of indoor and out-door drinking water in kabera sub-location of Nairobi, Kenya


J. K. Chemuliti
P. B. Gathua
M. M Kyule
F. M. Njeruh

Abstract

Objectives: To compare the bacteriological quality of out-house (tank or standpipe) water and in-house drinking water (storage containers) and determine the risk factors influencing it.


Design: A cross-sectional study.


Setting: The study was carried out in Kibera slums located 7 km southwest from the Nairobi City centre.


Subjects: Water samples from twenty outside tanks/standpipes and sixty from in-house water storage containers.


Main outcome measures: Pour plate method was used to enumerate total bacterial counts in water, while the multiple tube technique was used to determine faecal coliform (FC) and faecal streptococci (FS) numbers. A questionnaire and environmental observation were used to determine the risk factors influencing bacteriological quality of water.


Results: The mean total bacterial counts (TBC) for out-house water was 46.6 per 100 ml while that for in-house water was 818.2 per 100 ml. Faecal coliforms were isolated from 7 (35%) standpipes and 57 (95%) in-house storage containers. The mean faecal coliform count was 93 and 103.4 per 100 ml for out-house and in-house water, respectively. The counts were significantly higher in the latter. Faecal streptococci were isolated from 2 (10%) standpipes and 37 (61.7%) in-house storage containers. The mean faecal streptococci counts were 35 and 65 per 100 ml for out-house and in-house water sources, respectively. Escherichia coli was isolated in 2 (10%) of out-house water and 30 (50%) of in-house. Of these, four were enteropathogenic, serotype 011 from one out-house water source and serotypes 011, 011, 0112ac from in-house water sources.


Conclusions: Bacteriological contamination of water at the source with a further deterioration between the collection points and homes was observed. A defective water delivery system and inadequate environmental sanitation were a potential source of contamination for out-house water. Scoops were a major source of contamination for stored water.



(East African Medical Journal: 2002 79(5): 271-273)

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eISSN: 0012-835X