Concentration Levels of Heavy Metals and Selected Ions in the Irrigation Water: The Case of Little Akaki River, Addis Ababa, Ethiopia

Abstract

Irrigable water resources have been challenged by the contamination of heavy metals and unwanted ions that impair plant growth and human health. It impaired the quality of edible fruit & vegetables. The objective of this study was to determine the concentration of heavy metals (Pb, Cd, Cr, and Cu) and selected ions (chloride, Na, Mg, Ca), and to evaluate its suitability for irrigation use. Water samples were collected from three various locations (the upstream, middle stream, and downstream) of the river. Temperature (T), EC, pH, and total dissolved solids (TDS) were tested onsite using handheld multiparameter testing equipment, while the heavy metals (Pb, Cd, Cr, and Cu) and selected ions (Chloride, Na, Mg, and Ca) of the water sample were analyzed using (ICP-OES). ANOVA test was conducted to examine the concentration variations of heavy metals and selected ions between the sampling locations along the river. The concentrations of (Pb and Cd) were found (2.5-3.9), (0.03-0.4) mg/L respectively, and (Cr and Cu) were below the detectible limit of the (ICP-OES) equipment. Cadmium (Cd) was found to be higher than the permissible limit of FAO (0.01mg/L) for irrigation water. There was no significant variation of heavy metals and selected ions between the sampling locations.