Assessment of water pollution in Kampala industrial business park, Namanve micro catchment.

Abstract

The water quality in Namanve catchment along the Kampala Industrial Business Park is steadily deteriorating due to increased contaminants from runoff and discharge from the industrial developments. Coupled with urban growth and population increase, industrial expansion threatens the quality of surface and underground water sources. This study was conducted to understand water quality changes in the Namanve sub-catchment due to increased industrialization in the Kampala Industrial Business Park. A field reconnaissance visit was conducted at Namanve to identify the potential pollution sources in the Industrial Park. Sampling of industrial wastewater discharge, sediments and natural water streams from the three segments in the study area (upstream, industrial section and downstream) was conducted. Physiochemical and heavy metal analysis was done at Entebbe's Ministry of Water Laboratory. The extent of pollution in the KIBP was determined by comparing the concentration of heavy metals with the NEMA and WHO standards. The enrichment factor was used to determine the effect of chemical pollution from industrial development on the receiving natural stream in the Namanve micro-catchment. The study showed that industrial waste water discharge points had highest levels of cobalt (0.0112±0.00027ppm), Lead (0.08627±0.000713 ppm) and Manganese (1.6502±0.014 ppm) at Uganda batteries Ltd and they were all higher than the NEMA and WHO standards. For sediments, steel industries (Roofings and Steel and Tube) registered significantly higher levels of heavy metals (Cd=0.9279±0.0094, Pb=177.7±3.45, Co=14.15±0.242 ppm) than other industries (p<0.05). Roofings registered high levels of Mn=459.3±4.82 ppm and Plaskon paints registered higher levels of Cr (283.8±3.8) and Ni (40.67±0.617 ppm), all these values were higher than NEMA and WHO standards. The study also showed that the concentration of heavy metals, was significantly higher downstream of the industrial development compared to the levels upstream (p<0.05). Levels of Pb, Co, Cr and Ni in Namanve downstream were 123.19±2.212 ppm, 14.2±0.329 ppm, 135.28±2.884 ppm and 26.03±0.663ppm respectively. While levels of Pb, Co, Cr and Ni in the upstream were 24.997±2.212, 7.32±0.329, 64.23±2.884 and 22.64±0.663ppm respectively higher than the NEMA standards. This study also showed higher concentrations of Cd (1.448±0.026 ppm), Cr (135.278±2.884 ppm), Pb (123.186±2.213 ppm), Co (14.217±0.329 ppm), Ni (26.025±0.663), and Mn (861.721±22.161 ppm) in downstream than the upstream, however the concentration of As (0.0067±0.0002) and Hg (0.00067±0.0002 ppm) were higher in the upstream than the downstream and the NEMA and WHO standards. Therefore, continuous monitoring of wastewater discharges from the Industries by NEMA is recommended. The Industry Operators should improve the efficiency of waste treatment Practices to reduce the pollution in the receiving natural water streams in Namanve micro catchment.