Abstract
Limnological study of Erin-Ijesha waterfalls was carried on the 9th of January, 2024. Water samples were collected on an hourly basis (from 8am to 4pm) and analyzed for physiochemical parameters such as temperature, total dissolved solid (TDS), conductivity, pH, dissolved oxygen (DO), biological oxygen demand (BOD), total alkalinity, total hardness, calcium, magnesium, phosphate, sulphate, and nitrate. Periphyton samples were also collected from different substrate for algal analysis, identification and taxonomic studies. Using physiochemical, biological parameters and Palmer’s Index of Pollution, the quality of Erin-Ijesha waterfalls was determined. Results showed that the physiochemical parameters ranged from 19 – 26.5℃ for water temperature, 6 – 13NTU for turbidity, 1 – 4PtCoU for color, 14 – 16mg/L for TDS, 29 - 32S/cm for conductivity, 6.42 – 6.65 for pH, 8 – 10.5mg/L for dissolved solid, 4 - 6mg/L for BOD, 2.5 – 6.25mg/L for total alkalinity, 1 – 3mg/L for sulphate, 0.09 – 0.49mg/L for phosphate, 0.2 – 0.7mg/L for nitrate, 5 – 15 mg/L for total hardness, 2 – 4 mg/L for calcium, and 0.61 – 2.44mg/L for magnesium. Periphyton taxa consisted of 3 divisions – Bacillariophyta (39.5%), Chlorophyta (43.4%), and Cyanophyta (17.1%). The most commonly occurring species were from the genus Synedra, Spirogyra and Navicula. Palmer’s pollution index score was 19 which indicated some degree of probable organic pollution. However, all of the physiochemical parameters studied fell within the permissible limits set by the World Health Organization for drinking water and as such the water fall can be regarded as pristine.
