Pollution status of Tinishu Akaki River and its tributaries (Ethiopia) evaluated using physico-chemical parameters, major ions, and nutrients

Abstract

The present investigation provides data on physico-chemical parameters, some major ions and nutrients on water samples of Tinishu Akaki River (TAR), Ethiopia. The pH, temperature, electrical conductivity, total dissolved solids (TDS), dissolved oxygen (DO), chemical oxygen demand (COD), biological oxygen demand (BOD), Ca²⁺, Mg²⁺, HCO₃^-, SO₄^2-, NO₃^-, NO₂^-, PO₄^3-, Cl^- and NH₃ have been determined to asses the chemical status and pollution levels of the TAR and its tributaries. The values of certain parameters have been evaluated with respect to the acceptable standard limits for drinking and surface water to indicate the pollution level of the TAR. Increasing in BOD, nitrite, ammonia and phosphate and decreasing in DO concentrations downstream of the TAR were observed with increasing domestic, industrial and agricultural activities. The mean Ca²⁺, Mg²⁺, Cl^-, SO₄^2-, HCO₃^-, NO₃^- and PO₄^3- concentrations exceeded their most common natural concentrations' (MCNC) in world rivers by a factor of 6.3, 7.6, 27.2, 6.8, 9.2, 19 and 390, respectively.

KEY WORDS: Tinishu Akaki River, Water pollution, Ethiopia

Bull. Chem. Soc. Ethiop. 2007, 21(1), 13-22.