Microbial quality of utility water at universities in Nigeria

Abstract

Aims: Water is described as safe and wholesome when it is free from pathogenic microorganisms and chemical substances that are hazardous to human health. This study aimed to investigate the microbial quality of water used for drinking, cooking, bathing and other purposes at universities in Nigeria. Methodology and results: Water samples were collected from forty-four storage tanks across four selected universities. Total viable bacteria in the water samples were cultivated using the plate count agar. The isolation of total coliform and Escherichia coli were carried out on Harlequin™ E. coli/coliform agar (HA) medium, while media-faecal coliform was used for faecal coliform employing the membrane filtration technique. Physicochemical parameters such as alkalinity, pH, total alkalinity, total dissolved solid, total suspended solid, electrical conductivity, total hardness, fluoride and chloride ion concentrations, were evaluated in accordance with standard procedures. Data were compared statistically using MedCalc statistical software. Considering the heterotrophic bacterial counts, all water samples were unsatisfactory. For the total coliform counts, 50% of samples were satisfactory but suspicious, while remaining 50% were unsatisfactory. Faecal coliforms results showed that 50% of samples gave excellent quality, 25% showed satisfactory but suspicious quality, while 25% showed unsatisfactory result. There were no significant differences in the total viable, total coliform and E. coli counts of water sampled from universities A and D (p>0.05). The predominant bacterial species was Pseudomonas aeruginosa (23.17%), while the least encountered was Salmonella typhimurium (2.44%). All physicochemical parameters tested were within the acceptable limit. Conclusion, significance and impact of study: This study revealed that the water used by students of studied universities was contaminated with potential bacterial pathogens. However, all physicochemical parameters tested were within the permissible standard limits and satisfied the requirements for domestic utility.