Analysis of Some Physico-Chemical Parameters and of Selected Heavy Metals In-Stream Water of Asessa Town; West Arsi Zone, Oromia Region state, Ethiopia

Abstract

Water is the most important resource which influences human life. Runoff from agricultural and urban areas hurts water quality. Asessa stream water is well-known water that the town’s resident populations used for household consumption and drinking purposes. Hence, this study was designed to determine concentrations of selected metals (Na, K, Mg, Ca, Cr, Mn, Fe, Cu, Zn, Cd, and Pb) in steam water inthe ItuBollo, Kawa, and Targage districts of West Arsi Zone, Asessa town, Oromia regional state, Ethiopia. An acid digestion procedure of stream water samples was employed during sample digestionbefore Flame Atomic Absorption Spectroscopy (FAAS) measurement for the heavy metals and the photometric method for other metals. The method followed during the analysis was validated and the recovery value varied from 91.1‒113% whereas the obtained %RSD was <8.57%, indicating that the method employedhas acceptable accuracy and precision. In addition to selected heavy metals, the physicochemical properties of the water samples have also been determined. The physicochemical parameters of water like NO3 - ,TDS, Temperature, Conductivity, Turbidity, pH, PO4 3-, SO4 - , Cl- , DO, BOD5, COD, Alkalinity and Total Hardness were studied and the mean concentration range for three sampling sites were presented as 0.22-0.69mg/L, 55.46-65.25mg/L, 23.17-25.00°C, 114.93- 120.60 µS/cm, 0.48- 1.27NTU, 7.43- 7.57, 0.03-0.09 mg/L, 2.87-5.33 mg/L, 10.97-13.90 mg/L, 3-3.7 mg/L, 4.47-4.96 mg/L, 11.51-14.36 mg/L , 25.01-28.18 mg/L and 65.77-78.4 mg/L, respectively. The values of physicochemical parameters obtained for the sample analyzed from three sites were in the range of standard international guidelines for drinking water. The metal mean concentrations found in three stream water samples were ranged from 29.46-34.45 mg/L, 19.46-24.47 mg/L, 12.70-15.19 mg/L, 20.17-22.99 mg/L, 0.033-0.05 mg/L, 1.04-1.07 mg/L,0.31- 0.81 mg/L, 0.03-0.11 mg/L, 0.3-1.19 mg/L, 0.013-0.03 mg/L, 0.03-0.04 mg/L for Na, K, Mg, Ca, Cr, Mn, Fe, Cu, Zn, Cd and Pb respectively.Thus, all physicochemical parameters and most of the metals analyzed in Asessa stream water were in the range of permissible limit, except for Cd, Pb, Fe, and Mn, which were above the range of permissible limit for drinking water set by WHO (2008),and ESA(2013)