Spatial and Temporal Variations in Physicochemical Properties of an Aquatic Environment

Abstract

The study was carried out to evaluate spatial and temporal variations in the levels of some physicochemical parameters in water and sediments from Mpape River, Abuja, Nigeria. The samples were collected along the river bank in dry and rainy seasons from five (5) locations and were analysed using standard methods. Levels of pH, nitrate, phosphate, and biochemical oxygen demand (BOD) in water did not vary according to sites. However, the highest levels of electrical conductivity (EC) and total dissolved solids (TDS) were recorded at site 4 for both seasons. During the dry season, levels of pH (7.36±0.16), EC (300.73±0.05 µs/cm), TDS (185.11±0.10 mg/L), BOD (0.98±0.30 mg/L), SO42- (9.8±0.14 mg/L) and Cl- (38.00±0.15 mg/L) in water were higher. Concentrations (3.42±0.10 mg/L) of dissolved oxygen (DO), PO43- (5.66±0.11 mg/L) and NO3- (0.21±0.06 mg/L) increased in rainy season. In sediments, levels of physicochemical parameters did not vary according to sites, except for PO43- and organic matter (OM). pH of sediments was more acidic (6.23±0.05) and higher in the dry season. Levels of OM (2.66±0.11 %), PO43- (5.06 mg/Kg), NO3- (0.21±0.09 mg/Kg), CEC (0.29±0.05 Cmol/Kg) and Cl- (0.17±0.02 mg/Kg) in sediments were higher in rainy season. Levels of physicochemical parameters in water and sediments for the two seasons were not significantly different (P ≤ .05), except for BOD, SO42- and Cl- in water. Levels of physicochemical parameters of water were within the WHO/FAO permissible limits for irrigation. The acidic nature of sediments may lead to remobilization of heavy metals adsorbed onto the sediment surfaces into the water column, which may result to pollution.