Bacteriological Evaluation Of Groundwater In Ekiti- State, Southwestern Nigeria

Drinking contaminated groundwater can have serious health effects. Bacterial assessment of groundwater in Ekiti State was carried out to determine its potability and source(s) of pollutants. Consequently, 73 groundwater samples were collected for bacterial analysis and NO3 determination. At each location, depth of each well and depth to water table were measured using dipmeter. Temperature (°C), EC (μS/cm) and pH were measured insitu using a multiparameter potable meter (model Testr-35). Subsequently, the bacteriological analysis was carried out using nutrient agar medium to obtain plate count of living bacteria (viable cell count) while Coliform count was achieved using a lactose medium inoculated with serial dilution of the sample. Nitrate (NO3 ) concentrations in the groundwater were determined colorimetrically by Spectronic -20 (Gallenkamp, UK). In situ measurements revealed that pH ranged from 6.0 – 8.9 (av. 6.87), NO3 (mg/L) 1.2 to 19 (av. 6.86) mg/L while EC<1000μS/cm for all sampled groundwater. Virtually all samples tested positive to bacterial contamination with coliform count ranging from 0 8 (av. 2.15) cfu/100mL and total bacteria count (TBC) from 2 – 25 (av. 9.42) cfu/100ml. The groundwater in the study area is low mineralized fresh water. However, it has been polluted bacteriologically arising principally from surface phenomena of improper disposal of wastes and human faeces.