Physicochemical and Bacteriological Quality of Drinking Water Sources in Biu Metropolis, Borno State, Nigeria

Abstract

Access to safe drinking water remains a critical public health concern in rural communities of northeastern Nigeria. This study assessed the physicochemical and microbiological quality of drinking water from different sources in Biu Local Government Area, Borno State, to evaluate compliance with World Health Organization (WHO) standards. Water samples were collected from wells, boreholes, taps, and packaged sachets across five communities: Dugja, Galdimare, Zarawuyaku, Yawi, and Sulumtha. Physicochemical parameters including pH, temperature, total alkalinity, hardness, colour, odour, and taste were analysed following standard methods. Microbiological quality was assessed using the pour plate technique for Total Viable Counts and the tube fermentation technique for Most Probable Number of coliforms. Bacterial isolates were identified using standard microbiological techniques. All well, tap, and borehole samples tested positive for coliforms and exhibited high bacterial viable counts, indicating significant faecal contamination. Although sachet water samples showed comparatively lower coliform counts, they still failed to meet the WHO standard of 0 CFU/100 ml for drinking water. Seven bacterial isolates were identified: Escherichia coli, Klebsiella sp., Proteus sp., Enterobacter aerogenes, Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus sp. Gram-negative bacilli were more prevalent than Gram-positive bacteria. E. coli exhibited the highest frequency of occurrence (32.4%), followed by Klebsiella sp. (21.6%), while Proteus sp., S. aureus, and E. aerogenes showed the lowest occurrence rates (5.4% each). Despite variations in contamination levels across sources, none consistently met the zero-coliform standard for potable water. The frequent detection of faecal coliforms and pathogenic bacteria, particularly in wells and storage systems, indicates serious deficiencies in existing water safety measures. The widespread contamination of drinking water sources poses significant public health risks in the study area. These findings underscore the urgent need for improved source protection, strengthened treatment processes, and routine microbiological monitoring to reduce waterborne disease risks. Community education on proper water handling and storage practices is also recommended to safeguard public health.