ABSTRACT
Water quality assessment of Okhuaihe River in Edo state was carried out between February, 2020 and July, 2020. A total of 18 water samples were collected from three (3) Stations over a period of six months at monthly intervals. Water samples were collected for physical and chemical parameter analysis and also periphyton assessment. The biological, chemical and physical parameters of the river were determined. Station 1- 3 had values which were above the World Health Organization (WHO) for drinking water. Parameters such as phosphate values ranged from 0.11 mg/l to 1.27 mg/l; pH values from 3.35 to 8.74; DO values from 7.6 mg/l to 12.8 mg/l; and BOD values from 2.8 mg/l to 6.68 mg/l. All other physicochemical parameters (air temperature from 25˚C - 31˚C; water temperature from 21˚C to 28˚C; alkalinity from 30mg/l to 70 mg/l. The range of Sulphate was from 0 mg/l to 11 mg/l; Nitrate 25 mg/l to 31 mg/l; Conductivity from 12 mg/l to 18 mg/l; total hardness from 7.2 mg/l to 17.6 mg/l; TDS from 6mg/l to 10mg/l) were below the World Health Organization (WHO) permissible limits of <40, <40, 120 mg/l, 250 mg/l, 45 mg/l, 750 mg/l, 300mg/l,500 mg/l respectively. The periphyton flora of Okhuaihe River is composed of 167 taxa, belonging to 5 divisions: the division Bacillariophyta consisted of 65.26%, Chlorophyta consisted of 18. 56%, Cyanophya consisted of 8.98%, Pyrrophyta 0.59% and Euglenophyta consisted 6.58%. Bacillariophyta was represented , Notably by Cyclotella, Brachysira, Hantzschia, Gomphonema, Eunotia, Fragillaria, Synedra, Halamphora, Actinella, Frustulia, Encyonopsis, Diploneis, Luticola, Kobayasiella, Navicula, Cymbopleura, Pinnularia, Stauroneis, Nitzschia and Tabellaria. Chlorophyta was represented by Coelastrum, Klebsormidium, Scenedesmus, Oedogonium, Ulothrix, Gonium, Actinotaenium, Bambusina, Closterium, Cosmarium, Spirogyra and Cladophora. Cyanophyta was represented by Anabaena, Oscillatoria, Merismopedia, Scytonema, Jaaginema, and Phormidium. Euglenophyta was represented by Euglena, Lepocinclis, Phacus, Trachelomonas and Strombomonas. Pyrrophyta was represented by Peridinium. Using Palmer Pollution Indices it showed from 0 -17. Values of 0 – 10 indicate less organic pollution while > 17 refer to probable organic pollution. Efforts should consequently be made by regulating authorities to ensure that there is no further deterioration in the water quality of the Okhuaihe River by monitoring the activities in the river.
