Assessment of Bacteriological Contamination of Hand-Dug Wells in Rural and Urban Areas in Ondo State, Nigeria

Abstract

The study analysed the total bacteria, total coliform and Escherichia coli (E. coli) concentrations of ten randomly selected hand-dug groundwater wells: five each from Alagbaka (Urban area) and another five from Ijare communities (Rural area) in Ondo State. Collins and Lyne’s pour plate method was used for the laboratory analysis. The laboratory results showed that 30%, 90% and 0% of the groundwater samples were above the WHO drinking water standards for total bacteria, total coliform and E. coli, respectively. Furthermore, the groundwater samples collected in the urban study area had total bacterial and total coliform mean levels of 24 and 15 cfu/100mL respectively compared to those of the rural study area with mean concentrations of 15 and 5 cfu/100mL, respectively. There was however no E. coli in the groundwater of both areas studies indicating the absence of faecal contamination in groundwater. It can therefore be concluded that there is a higher risk of microbial contamination of groundwater in urban land use than in rural land use and that groundwater in the study areas is unsafe for consumption unless it is first treated with appropriate treatment methods. For future research, the contamination level of other micro-organisms such as fungi, viruses, protozoa etc. should be assessed in study areas, as well the sources of microbial contamination in groundwater.