ABSTRACT

Background- Groundwater is an important source of water for drinking and other purposes in Ile-Oluji, Nigeria. The sources of microbial and chemical contamination of groundwater are diverse and could have serious implications for public health. Objective- This study was carried out to determine the physicochemical and microbiological parameters in water samples collected from five hand-dug wells at selected locations in Ile-Oluji, Nigeria. Materials and Methods- Five samples (four sources close to filling stations and one control) were collected during the dry season (DS) and rainy season (RS) respectively, and analyzed for relevant physicochemical and bacteriological properties, using standard analytical procedures. Results- The data (in mg/L) obtained for the five analyzed samples, including the control were: alkalinity (17.9 – 59.0); total hardness (32.0 – 114); calcium hardness (18.0 – 59.0); magnesium hardness (18.0 – 57.0); chloride (32.0 – 48.0); total dissolved solids (60.0 – 130); free carbon dioxide (70.4 – 132); acidity (3.80 – 10.2), total suspended solids (0.20 – 0.45); nitrates (0.15 – 0.30); phosphates (0.15 – 0.35). The pH ranged from 5.15 – 7.23; temperature, 26.2 – 29.2 ^ºC; turbidity, 4.00 – 7.00 NTU and conductivity, 38.7 – 84.5 µS/cm. The total bacterial count (TBC) and total fungal count (TFC) ranged from 2.79 x 10⁸ to 9.66 x 10⁸ and 1.00 x 10⁵ to 1.78 x 10⁶ cfu/mL respectively. Coliform was not detected from all the samples collected. The average values of physicochemical for all the wells were within the maximum permissible limits (MPL) specified by World Health Organization (WHO), United States Environmental Protection Agency (USEPA) and Nigerian Industrial Standard (NIS) except for turbidity and bacteriological properties. The wells located close to filling stations exhibited varying degrees of contamination and were generally more polluted than the control well. Furthermore, these parameters were observed to be higher in the dry season compared to rainy season. There was a significant difference at p < 0.05 in the levels of physicochemical parameters investigated during the (DS) and (RS) seasons. Conclusion- water from these wells including the control well is unsuitable for drinking and other domestic applications. It is recommended that the wells must be treated adequately to avoid possible health and other consequences of using the water from these wells. Besides, government should enact appropriate legislation to prohibit location of wells within the proximity of filling stations.

Keywords: Ile-Oluji Nigeria, groundwater, filling stations, contamination, microbial loads, physicochemical properties.