Water pollution by natural inorganic chemicals in the central part of the Main Ethiopian Rift

The natural surface water and shallow groundwater quality in the Ethiopian Rift is influenced by excessive input of fluoride and some inorganic chemical constituents such as Li, Sr, Pb, Cu and Hg from the deep groundwater system. The surface water bodies are characterised by high fluoride, bicarbonate and chloride concentration far above the recommended consumption limit. The quality of surface water in the Ethiopian Rift is influenced by the complex geological activities, which increase the concentration of undesirable chemical constituents in surface waters by transfer from deep groundwater in the form of thermal springs, geysers and fumaroles. In fact, the concentration of some of the aforementioned chemical constituents highly exceeds the consumption limits giving rise to serious health problems to the local population. SINET: Ethiopian Journal of Science Vol. 23, No. 2 (December 2000), pp. 197-214 Key words/phrases: Deep groundwater, inorganic chemical pollutants, Main Ethiopian Rift, teeth mottling, thermal spring