Assessment of the effect of cement industry effluent discharge on water quality of Ngo River in Benue, Nigeria

Abstract

Ngo River in Gboko, Benue State, Nigeria which serves as a source of water for domestic and agricultural purposes for the agrarian community receives effluent from Dangote Cement factory. Physicochemical analysis of the effluent outfall and water samples collected along 15 km of the river stretch were carried out in dry and wet seasons respectively. The results obtained were compared to FEPA, WHO and NESREA Standards. For effluent outfall, Temperature, TDS, pH, EC, BOD, COD, sulphate and chloride, total hardness, calcium and magnesium, were found to be within the FEPA standards, while TSS, turbidity, and nitrate, were above the standards. Along 15 km study reach, mean temperature range of 32.4oC to 29.0oC, a TSS of 224 mg/l to 218 mg/l, a turbidity of 45 NTU to 42 NTU, and DO of 1.6 mg/l to 1.2 mg/l were obtain during the dry season, while mean temperature range of 36.8^oC to 36.6^oC, a TSS of 255 mg/l to 252 mg/l, turbidity of 176 NTU to 168 NTU, and DO 2.8 mg/l to 2. 6 mg/l were obtained during the wet seasons. These results were above WHO and NESREA temperature (25^oC drinking water), TSS (30 mg/l domestic and 100 mg/l agriculture) water use, 5 NTU turbidity, and 5mg/l to 7.5mg/l DO standards. The effluent is relatively treated and effects such as aquatic depletion in the environment, decreased soil pore size and decreased permeability in the use of the water for irrigation, and water related diseases are not ruled out.

Keywords: Cement industry, Effluent discharge, Water quality, Ngo River.