ABSTRACT
Water is one of the most abundant and essential resources of man, and occupies about 70% of earth’s surface. About 97% of this volume is contained in the oceans, 21% in polar ice and glaciers, 0.3-0.8% is found underground, 0.009% in inland freshwaters such as lakes, while 0.00009% is contained in rivers. Saltwater has the highest percentage, accounting for 97% of the entire water volume while freshwater accounts for only 3%. The aim of this study is to carry out a comparative assessment of the water quality of borehole water stored in overhead and underground tanks in Ugbowo, Benin city. The water sample was subjected to physical (Temperature, colour, turbidity); chemical (pH, conductivity, nitrate content, phosphate content, BOD, COD and total dissolved solid) and biological parameter (E. coli and total coliform count TCC). The results recorded showed the mean value for temperature (30.2 ± 1.303), pH (6.02 ± 0.41), colour (2.4 ± 1.14), suspended solids (0.4 ± 0.54), electrical conductivity (37.2 ± 18.25), total dissolved solids (18.6 ± 9.12), dissolved oxygen (5.24 ± 0.43), biochemical oxygen demand (1.96 ± 0.51), Ca (2.88±1.21), Mg (4.08±5.35), K (0.76 ± 0.16), P (0.14 ± 0.004), nitrate (0.05 ± 0.02), coliform (2.0 ± 2.0) and E. coli (0.20 ± 0.44) for overhead tanks. In contrast, underground water tank showed mean values for temperature (28.4 ± 0.547), pH (6.60 ± 0.62), colour (1.6 ± 1.67), suspended solids (nil), electrical conductivity (84.8 ± 49.52), total dissolved solids (42.4 ± 24.76), dissolved oxygen (6.08 ± 1.54), biochemical oxygen demand (1.88 ± 0.31), Ca (7.69±3.70), Mg (2.62 ± 1.95), K (0.83 ± 0.47), P (0.13 ± 0.006), nitrate (0.04 ± 0.02), coliform (3.8 ± 1.48) and E. coli (1.60 ± 0.89). In conclusion, the overhead tank is more susceptible to algae growth and varying temperatures when exposed to sunlight which can impact water quality. Although it offers a more versatile use in both drinking and washing purposes as it contains a lower coliform count and calcium content compared to the underground water tank.
