Seasonal variations in physicochemistry of water and sediment of a degraded freshwater wetland ecosystem: a case study of Ipare wetland in Ondo State, Nigeria

Abstract

This study was carried out to investigate the seasonal variations (dry and rainy seasons) in physicochemical characteristics of a degraded freshwater wetland in Ipare, Ondo State. The physicochemical parameters of water and sediment samples from three degraded stations and a control (non-degraded site) were analysed using standard analytical method. Results showed that sodium and chloride concentrations in water ranged from 1329 to 1583 mg/l and 7373.9 to 9345.5 mg/l (dry season), and 56.87 to 207.06 mg/l and 130.4 to 513.76 mg/l (rainy season), respectively. The sediment showed sodium and chloride concentrations that ranged from 738.08 to 742.33 mg/kg and 1749.69 to 1793.94 mg/kg (dry season), and 410.25 to 411.93 mg/kg and 702.82 to 848.09 mg/kg (rainy season), respectively. Values for the control for sodium were 29.59 mg/l and 58.62 mg/kg (dry season) and 7.11mg/l and 9.6 mg/kg (wet season), while chloride values were 61.2 mg/l and 126.56 mg/kg (dry season) and 15.81 mg/l and 17.52 mg/l (rainy season) for water and sediment, respectively. All other physicochemical parameters were altered due to the variation in season. Statistical analysis showed a significant difference (p< 0.05) between the degraded sites and the control. The study showed that season and anthropogenic activities have significant effects on the physicochemical characteristics of sediment and water in the freshwater wetland and, therefore, contribute to wetland degradation.