INVESTIGATION OF INFLUENT SOURCE WATER QUALITY AND FISHING PRACTICES OF KOKA RESERVOIR, ETHIOPIA

Abstract

Water pollution from different sources are serious problem in most of the developing countries of the world like Africa. Most of Ethiopian industries and Flower farms release their untreated or partially treated wastewaters into nearby surface waters. The aim of this study to investigated influent sources water quality and fishing practices of the Koka Reservoir. Water and sediments samples were collected from eight purposively selected sampling stations and characterize. Fish sample also collected from three stations. Some selected nutrients and physiochemical parameters investigate from water samples while nine metals from water, sediments and fish organs (gills, liver and muscle) were analyzed using standard protocols. Fishing practices examined using questioner dispatch (face to face interview). Data was analyzed using SPSS two-way ANOVA (p ≤ 0.05). The mean values for the Physiochemical parameters ranged from, 1.16-12.12 (PO4 -3 ), 2.19-24 (TP), 16.24-458.3 (NH3) and 35.16-763.23 mg/L (TN), 711-19403 /cm (EC), 171-11, 833 mg/L (TDS), 12-915 mg/L (BOD5) and 0.17-7.74 mg/L (DO) in influents water. Heavy metal concentration in influents water (mg/L) were, 0.12-6.81 (Fe), bdl-4.45 (Pb), bdl- 0.63 (Mn), 0.12-176.23 (Cr), 0.02-0.26 (Cd), whereas in sediments ranged from, 3,705.7- 6,308.1 (Fe), 4.74-15.9 (Pb), 131.52-514.8 (Mn), 2.29-550.2 (Cr),0.34-4.4 (Cd). The results revealed significant difference in mean values of nutrient and physiochemical parameters among the eight sites and seasons (p<0.05) and also some significant correlations among the tested parameters. In Koka Reservoir fishing activates is always and there is high demand, decrement of production and water quality. Mainly four type of fish types and fishing gear. Nile tilapia is the most abundant, required, while Barbus most decline fish species. In conclusion the highest concentration of metal in sediments and lowest in water and in relation to fish organ highest concentration in liver. While the lowest in muscle, which is within the WHO acceptable range hence no health effect for human consumption. Relatively Ethiopian tannery and Flower farm effluents contribute high pollution and their effluent concentration exceed the WHO and EEPA limit for drinking water and aquatic life hence it need high attention with respective bodies.