Physico-chemical water quality characteristics of upper Ebonyi River, Enugu State, Nigeria

Abstract

The physico-chemical characteristics of upper Ebonyi River, Nigeria were assessed at four locations, from September 2014 to December 2014, using standard methods, thereby providing information for documentation and the determination of pollution status in comparison with World Health Standards. Parameters, such as colour, calcium, pH, total dissolved solids (TDS), alkalinity, chloride, dissolved oxygen (DO), silica, biochemical oxygen demand (BOD₅), phosphate, nitrate, potassium and lead did not significantly differ (p < 0.05) between the locations. However, water temperature, depth, flow rate, transparency and iron differed significantly. Ambient temperature, water temperature, colour, pH, TDS, transparency, alkalinity, chloride, calcium, DO, silica, iron, BOD₅, phosphate, nitrate, potassium and lead differed significantly with time (months), whereas depth and flow rate showed no significant difference. The Water Quality Index showed a medium range. The river was moderately polluted (using BOD₅ level as a pollution index: BOD₅ = 2.06 ± 0.92 mg l^–1), shallow (41.66 ± 9.80 cm), highly transparent (26.22 ± 4.06 cm), slightly acidic (pH 6.8 ± 0.29), free of mercury, whereas phosphate (11.72 ± 2.45 mg l⁻¹), iron (0.44 ± 0.13 mg l⁻¹) and lead (0.09 ± 0.03 mg l⁻¹) levels were above Word Health Standards for drinking water quality requirements. Water from the river should be used with caution for domestic and bathing purposes, because high lead consumption might cause saturnism.

Keywords: anthropogenic effects, iron, lead, saturnism, water pollution, water quality