Physicochemical and bacteriological analysis of borehole water from eight selected locations within Benin Metropolis, Edo State, Nigeria

Abstract

In Nigeria, borehole water is a dominant source of drinking water. The quality of the water has diminished substantially due to various  anthropogenic activities. Thus, this study seeks to x-ray the physicochemical and bacteriological quality of borehole water in some  crowded localities in Benin City, Edo State, Nigeria. Heterotrophic plate count and total coliform count were carried out sing pour plate  method. Antibiotic susceptibility test was done using the Kirby-Bauerdisc diffusion test. Except for one case each of iron (0.32 ± 0.11), Manganese (0.16 ± 0.06), Cadmium (0.005 ± 0.01) and Lead (0.12 ± 0.01) that were found to be above the recommended WHO and  NAFDAC limits, the heavy metals had concentration levels that were within the stipulated limits. Isolates were phenotypically and molecularly identified as:Klebsiella aerogenes, strain OBANOR&OKWU 100; Streptococcus pneumoniae, OBANOR&OKWU 101;  Pseudomonas aeruginosa, OBANOR&OKWU 102; Staphylococcus aureus, OBANOR&OKWU 103 and Micrococcus lylae, OBANOR&OKWU  104 using the 16S rRNA gene analysis. Isolates were deposited in the United States GenBank under accession numbers: OK017170, OK017423, OK017480, OK017486 and OK019091 respectively. Generally, the isolates showed low resistance rates (14.29 % - 19.05 %) to the  antibiotics used in this study except for Cefuroxime and Ampicillin with extremely high resistance rates of 80.95 % and 85.71 %  respectively. Majority of borehole water samples were found to be contaminated. This study highlights the need for continuous  monitoring and quality assessment of the borehole water available for consumption.