Environmental impact on the bacteriological quality of domestic water supplies in Lagos, Nigeria.

L Egwari,O O Aboaba

doi:10.1590/s0034-89102002000400019

Abstract

To assess the impact of town planning, infrastructure, sanitation and rainfall on the bacteriological quality of domestic water supplies. Water samples obtained from deep and shallow wells, boreholes and public taps were cultured to determine the most probable number of Escherichia coli and total coliform using the multiple tube technique. Presence of enteric pathogens was detected using selective and differential media. Samples were collected during both periods of heavy and low rainfall and from municipalities that are unique with respect to infrastructure planning, town planning and sanitation. Contamination of treated and pipe distributed water was related with distance of the collection point from a utility station. Faults in pipelines increased the rate of contamination (p<0.5) and this occurred mostly in densely populated areas with dilapidated infrastructure. Wastewater from drains was the main source of contamination of pipe-borne water. Shallow wells were more contaminated than deep wells and boreholes and contamination was higher during period of heavy rainfall (p<0.05). E. coli and enteric pathogens were isolated from contaminated supplies. Poor town planning, dilapidated infrastructure and indiscriminate siting of wells and boreholes contributed to the low bacteriological quality of domestic water supplies. Rainfall accentuated the impact.

Highlights

Water remains the major source of transmission of enteric pathogens in developing countries
Studies across the country have shown that viruses, bacteria, protozoa, and helminthes are variously responsible for diarrhea diseases in children.[1,10,15]
Chlorinated pipe-borne water samples obtained from water utility stations in the three municipalities contained no coliforms per 100 ml

Summary

Introduction

Water remains the major source of transmission of enteric pathogens in developing countries. In Nigeria, there is a high incidence of childhood diarrhea despite the intensive activities of the National Diarrhea Control Program This is due to the unavailability of potable water especially in rural communities, and mothers usually obtain water from unhygienic sources for preparing weaning foods. Babaniyi[4] (1991) in reviewing the prevalence of diarrhea in Nigerian children over a period of 9 to 12 years observed that 315,000 children under the age of 5 years died annually from this disease condition Children within this age range (0-5 years) are reported to experience on average 4.3 episodes of diarrhea annually.[16] Studies across the country have shown that viruses, bacteria, protozoa, and helminthes are variously responsible for diarrhea diseases in children.[1,10,15] In one study, bacteria caused 48.6% of the diarrhea cases, 30.6% were caused by viruses, 8.2% by enteric parasites (protozoa and helminthes), and 6.9% were of dual etiology.[1]

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Results

Conclusion