Microbial and Physicochemical Analysis of Borehole Water within Oza Nogogo, Agbor, Delta State

Abstract

This study assessed the physicochemical and microbiological quality of borehole water used for domestic purposes in Oza Nogogo, Agbor, Delta State, Nigeria. Fifteen borehole water samples were collected from Oza Nogogo, Alisor and Alizomor and subjected to standard microbiological and physicochemical analyses. We evaluated antibiotic susceptibility using the Kirby–Bauer disc diffusion method. Heterotrophic bacterial counts ranged from 36.67 ± 3.06 to 64.00 ± 2.65 CFU/mL, while total coliform counts ranged from 3.00 ± 0.00 to 43.67 ± 2.52 CFU/mL Faecal coliforms occurred in samples A1, A2, B2, C1 and C2, with values ranging from 2.33 ± 0.58 to 15.00 ± 2.65 CFU/mL Twelve bacterial isolates were characterized and comprised Escherichia coli, Klebsiella spp., Enterobacter spp., Proteus spp., Serratia marcescens, Citrobacter spp., Salmonella typhi, Enterococcus faecalis, Corynebacterium spp. and Clostridium spp. Gram-negative organisms accounted for 75.0% of the isolates. Antibiotic susceptibility results showed substantial resistance to several commonly used antibiotics, particularly amoxicillin, ampiclox and erythromycin, whereas ciprofloxacin, ofloxacin and sparfloxacin were comparatively more effective. pH ranged from 5.3 to 6.1, EC from 8 to 18 µS/cm, TDS from 4 to 9 ppm, temperature from 27.6 to 28.4 °C, TTA from 20 to 55 mg/L and hardness from 15.01 to 150.14 mg/L as CaCO3. ANOVA showed significant differences in pH, EC, TDS and TTA among sampling groups. The combined microbiological and physicochemical findings indicate that the borehole sources require regular monitoring and appropriate treatment before use for drinking or other domestic purposes.