An Assessment Of The Impact Of Industrial Effluent From A Kwekwe-Based Iron And Steel Company On Kwekwe River Water Quality

Abstract

The water quality of Kwekwe River, upstream and downstream of the industrial effluent discharge point was examined with the view of determining the effect of the effluent on water quality. Five sampling sites, each 20m long were selected along the river. Water and biological samples were collected between the months of April and June 2005. Both macroinvertebrates and water variable characteristics data were analysed for variations

using one-way analysis of variance (ANOVA). Hierarchical method, average linkage cluster analysis was applied to the mean values of the water variables for each site. Two clusters were produced, grouping the reference site and the two sites furthest from the discharge point. Water physico-chemical variables (total dissolved solids, chemical oxygen demand and conductivity), heavy metals (calcium, iron, manganese and

chromium), Average Score per Taxon (ASPT) score; metric and diversity indices changed markedly downstream (p<0.05). The river had the highest self-purification amounts with respect to total dissolved solids. The results of the study suggested that the effluent discharged into Kwekwe River have an adverse effect on water quality. Macroinvertebrate structure changed markedly downstream with a complete disappearance of taxa at the discharge point.