Research Article

Comparative Assessment of Bacterial Contamination in Institutional Tap Water and Vended Water (Meruwa) in Ogbia, Bayelsa State, Nigeria

Abstract

Background: Safe drinking water is essential for human health, yet bacterial contamination remains a pervasive challenge in resource limited settings. In many Nigerian communities, households supplement or replace tap water with water purchased from informal vendors, often referred to as Meruwa, under the assumption that vended water is safer. However, no prior study has systematically compared bacterial contamination in both institutional tap water and informal vended water in this region. Objective: This study compared contamination levels and bacterial species distribution between institutional tap water and vended water in Ogbia, Bayelsa State, Nigeria, and assessed compliance with World Health Organization drinking water standards. Methods: A total of 47 water samples were analyzed, comprising 23 tap water samples from six campus points and 24 vended water samples from vendors in Ogbia Main Town. Total bacterial counts and total coliform counts were determined using the plate count method on nutrient agar and MacConkey agar, respectively. Bacterial isolates were identified through Gram staining and biochemical characterization. Compliance was assessed against WHO guidelines of 0 CFU/100 mL for coliforms and less than 500 CFU/mL for heterotrophic bacteria. Results: All samples exceeded WHO standards. Tap water total bacterial counts ranged from 3.50 × 106 to 5.00 × 106 CFU/mL with a mean of 4.32 × 106 CFU/mL, and total coliform counts ranged from 3.00 × 106 to 3.80 × 106 CFU/mL with a mean of 3.21 × 106 CFU/mL. Vended water total bacterial counts ranged from 3.50 × 106 to 5.30 × 106 CFU/mL with a mean of 4.24 × 106 CFU/mL, and total coliform counts ranged from 3.00 × 106 to 4.00 × 106 CFU/mL with a mean of 3.21 × 106 CFU/mL. No significant difference was observed between water sources for total bacterial counts (p = 0.642) or total coliform counts (p = 0.981). Tap water isolates included Escherichia coli at 28.0%, Staphylococcus aureus at 28.0%, Pseudomonas aeruginosa at 20.0%, Klebsiella pneumoniae at 12.0%, and Enterobacter aerogenes at 12.0%. Vended water isolates comprised E. coli at 33.3%, Salmonella typhi at 25.0%, K. pneumoniae at 20.8%, and Citrobacter freundii at 20.8%. Species distribution differed significantly between sources (χ2 = 24.18, p = 0.0005). Compliance with WHO standards was 0% for both sources. Conclusion: Both water sources are universally contaminated with faecal and opportunistic pathogens, including S. S. typhi. The assumption that vended water is safer is unfounded. Routine monitoring, mandatory treatment of both sources, vendor certification, and targeted hygiene interventions are urgently needed.

Authors affiliation:

Ijeoma Festa Ndu (ORCID): Department of Medical Microbiology, Parasitology and Immunology, Faculty of Medical Laboratory Sciences, Federal University Otuoke, Bayelsa State, Nigeria.
Nathaniel Jack Festus: Department of Medical Microbiology, Parasitology and Immunology, Faculty of Medical Laboratory Sciences, Federal University Otuoke, Bayelsa State, Nigeria.

How To Cite: I.F. Ndu and N.J. Festus. Comparative Assessment of Bacterial Contamination in Institutional Tap Water and Vended Water (Meruwa) in Ogbia, Bayelsa State, Nigeria. Energy and Environmental Research, 2(2):1–7, 2026. https://doi.org/10.58614/eer221