Physicochemical Limnology and Water Quality Assessment of Ten Surface Water Bodies in Edo State, Nigeria

The objective of this paper was to assess the physicochemical limnology and water quality assessment of ten surface water bodies in Edo State, Nigeria to determine their suitability for drinking, provide information on water quality status to the concerned public as well as providing baseline information that can be used as reference for further studies using appropriate standard techniques. Results revealed that pH, colour, turbidity, total dissolved solids, electrical conductivity, total alkalinity, total hardness, calcium, magnesium, dissolved oxygen, biochemical oxygen demand, sulphate, nitrate and phosphate 5.52 – 7.06, 1.0 – 5.5 PtCoU, 3.5 -23.0 NTU, 11.0 -75.5 mg/L, 21.0 – 152.5µS/cm, 25.0 – 106.5 mg/L, 3.0 – 40.8 mg/L, 0.18 – 7.40 mg/L, 0.13 – 2.77 mg/L, 5.76 – 8.92 mg/L, 3.12 – 6.87 mg/L, 9.5 – 24.5 mg/L, 0.2 – 2.60 mg/L and 0.05 – 0.49 mg/L respectively. From the results of the physicochemical analyses, the water quality index score of the rivers was computed using the Weighted Arithmetic Water Quality Index method and the values obtained indicated that 60% of the sampled rivers were classified as having grade C quality (51 – 75), while 40% were of the grade D category (76 -100). Maximum index score (79.72) was recorded at Eruvbi River while the lowest index value (59.32) was redorded at Ugbogor River. Overall, this study found that the water quality of all chosen rivers is poor and unfit for drinking without previous treatment, although they are appropriate for irrigation and industrial usage.