Assessment of the Microbial and Physicochemical Quality of Water: Evidence from Selected Groundwater Sources from The Coastal Region of Ondo State, Nigeria

Abstract

The coastal area of Nigeria frequently experiences pollution of water due to various human activities that may compromise the quality of underground water. This study evaluated the microbial contamination and quality indicators of groundwater in the coastal environment of Ondo State, Nigeria. Nine underground water samples were collected from the study area and assayed using conventional microbiological techniques coupled with standard physical and chemical analytical procedures. Results revealed that all the samples had total viable bacterial counts, fungal counts and coliform counts which ranged from 61.25 to 85.32 CFU/100 mL, 10.00 to 35.32 SFU/100 mL and 6 – 24 MPN/100 mL respectively, which were higher than the set WHO limit. Results also revealed that the samples from Irele and Ese- Odo Local Governments Areas had acidic pH in the range of 4.20 -5.21 considered to be below the WHO permissible limit whereas only one of three samples from Ilaje Local Government had acidic pH of 5.23. The concentrations of the heavy metals varied among the samples with manganese (0.183-0.311) mg/L exceeding the 0.08 mg/L prescribed by the WHO. The high microbial load, acidic pH of 4.20 -5.23 in 77.78 % of samples and elevated amount of certain metals suggest the need for water quality monitoring and intervention by government and oil multinationals operating in the area noting that adequate supply of safe - drinking water will improve human health and reduce the burden of waterborne diseases.