Water Quality Assessment and Spatial Variation in Aba River Water, South-Eastern Nigeria

Abstract

The status of the Aba freshwater ecosystem (river) was assessed for the influence of human activities at differentsections of the river and its attendant effects on water parameters. To achieve this, samples of water were collected monthly from January to June 2020 at three sampling stations marked A1, A2, and A3 and were analysed on-site for water, electrical conductivity (EC), dissolved oxygen (DO), pH, salinity, total dissolved solids (TDS) and temperature with the aid of a handheld multi-parameter kit. Biochemical oxygen demand (BOD) was fixed onsiteand taken to the laboratory along with samples for potentially toxic metals (PTMs), Cd, Cu, Pb, Fe, and Zn),which were analysed by standard analytical procedure.Statistical variation across the sampling hotspots was determined with a one-way analysis of variance. The results indicated the average values of pH were moderately low in all the stations with little statistically variation (p˃ 0.05) between samples. The mean EC indicated station A1 (1394.32±152) had the highest concentration, followed by station A2 (972.14±52.22), and A3 (496.16±72.10) was the lowest. The mean salinity, TDS and Cl- followed a similar pattern as EC, with significant differences (p ˂ 0.05) in all the stations. DO values for A3 (4.90±0.37) were the highest while for A1 (3.34±0.21) they were the least. The mean BOD results for station A1 (6.54±5.54) were the highest whereas for A3 (3.28±0.66) they were the lowest. The value of metals across the stations indicated higher occurrence pattern: Fe˃ Zn ˃Cu˃ Cd˃ Cr˃ Pb. Generally, the concentrations of physicochemical and potentially toxic metal parameters were above the threshold for surface water and this deduced that the river was contaminated and needed urgent remediation. Also, the government should regulate the discharges of industrial effluents, agricultural wastes and sewage into the water body to safeguard the river from further deterioration.