Diagnosing the suitability of lake water for domestic and agricultural uses: a case study in eastern Ethiopia

Abstract

Lake Adele is one of the lakes giving incomparable economic benefits in Eastern Hararghe zone. It is being used for irrigation and water supply purposes, especially for animals. However, the lake water quality has not yet been analyzed even though it is traditionally believed that it has quality problems. This research was, thus, undertaken to evaluate the quality, identify the origin, and analyze the hydrochemical composition of the lake water. Three water samples were collected from the lake by a grab sampling method. Samples were analyzed for six physicochemical parameters (temperature, EC, TDS, TA, pH, and turbidity), major cations and anions, minor anions and trace metals using standard procedures. The laboratory measurements were weighed against the local and global standards. The results of the analysis revealed that the lake water has exceedingly intolerable levels of certain physical and chemical parameters. The GW-Chart software was also used to produce the piper diagram that can graphically show the origin and geochemical composition of the lake water, which revealed that the origin of the lake is deep groundwater with a major geochemical composition of sodium bicarbonate. It is concluded that the lake water has particularly excess turbidity and dangerous levels of nitrate (NO₃^-1), nitrite (NO₂^-), ammonia (NH₃), and lead (Pb) that would make it unsafe to use for drinking as well as excess levels of salinity, pH, and Sodium Adsorption Ratio (SAR) that would make it unfit to use for irrigation.

Keywords: Domestic use; Irrigation; Lake Adele; Major Ions; Origin and Geochemical Composition; Water Quality