Changes in the Physico-chemical Attributes of an Urban Stream in Jos, Nigeria

Abstract

River Dilimi originates from hills around old airport area in Jos. An important river flows across Jos City in central Nigeria. It was chosen for study in order to investigate the spatial and temporal variations in the physico-chemistry of its water. Five different locations were selected to reflect sections of possible human activities that are capable of changing the quality of its water. Generally, the surface water of the river was characterized by high turbidity (6 – 92 FTU), high conductivity (142 - 1125µmhoscm-1), moderate dissolved oxygen content (1.3 – 12mg/l), and high alkalinity (20 – 410mg/l). Nutrient elements, NO3-N and PO4-P recorded moderately high values of between 1.0 – 6.6mg/l and 0.6 – 2.9mg/l respectively. It was observed that significant variation exists in the habitat attributes and in the quality of the sampled waters with sampling periods. The pattern of variability observed in the study was largely affected by both the interplay of diffuse pollution from land based anthropogenic activities and from climate changes due to seasonal variation. Stream flow was correlated positively with turbidity (p < 0.05), depth (p < 0.01), width (p < 0.01), velocity (p < 0.01), and PO4-P (p < 0.01) concentration in water. However, conductivity and alkalinity correlated negatively with flow, turbidity, velocity and phosphate. The study indicates that increased nutrients input from activities within the catchments and terrestrial runoff are major threats to Dilimi River. With increasing population and urbanization, the water quality will continue to deteriorate.