Causes and impact of surface water pollution in Addis Ababa, Ethiopia

Abstract: Surface water is globally becoming more and more a scarce resource, and in Addis Ababa the capital of Ethiopia, river water quality has been degraded due to anthropological forcing for many years. Therefore, the study objective was to investigate causes and impact of surface water pollution in Kebena and Great Akaki rivers. The technical aspect of the study focused on analysing the parameters E. coli, phosphate, nitrate and total ammonia nitrogen in 34 different sampling sites in the western part of the Great Akaki catchment. The other aspect was to evaluate authorities’ and companies’ perspective on the water quality, usage and future plans to mitigate further pollution of rivers. Another perspective was to interview households and farmers regarding their view on usage, water quality and health risks. The main finding was a high surface water contamination in both Kebena and Akaki river, throughout the city, mostly from domestic, municipality and industrial wastewater and solid waste. E. coli concentrations exceeded thresholds given by WHO. Concentrations of phosphate and total ammonia nitrogen strongly indicated eutrophication. Nitrate values were lower than expected with no perceived healthrisk. The interview study with authorities, households and farmers indicated irrigation as the main usage. Little to moderate health risks perceived by farm users and high health risks perceived by authorities for farmers were found. Therefore, addressing a stronger collaboration between authorities and the local community is important. In addition, the implementation of mitigation strategies should be strengthened and the stakeholders need to be accountable for their actions. A continued monitoring of pollutants as well as a multi-sectoral approach to solidwaste and wastewater management will help improve the river water quality.