Quality of Water from Rift Valley Lakes of Ethiopia for Livestock Drinking
Water from five rift valley lakes (Awassa, Beseka, Chamo, Langano and Shala) of Ethiopia was sampled at the inlets, sites influenced by human activity and livestock drinking sites. Quality of water was evaluated based on physicochemical and microbiological properties, while suitability of the water for livestock drinking was evaluated by comparing the results with maximum levels which are safe if present in livestock drinking water. There was no difference in water quality parameters (P>0.05) among sampling sites but it varied among the lakes (P<0.01). Comparison of the measured parameters with guidelines shows that levels of magnesium, calcium, nitrate, nitrite and zinc in water of all lakes, temperature, alkalinity, salinity, potassium, chloride and bicarbonate in more than 80% of the samples (except Lake Shala) and pH and sodium in 60% of the samples were below the maximum permissible levels in livestock drinking water. Nevertheless, levels of iron, cadmium and total coliform count in all the samples, and chromium, copper and manganese in 93% of the samples were beyond the safe limits. Although consumption of water with relatively high concentrations of chemicals for short term may not affect animal performance, the high concentrations of toxic elements need due attention, since human health could be affected through residues in animal products. Based on this result, the lakes except Shala, can be considered safe drinking water sources for livestock. However, to make a concrete conclusion, it is necessary to undertake detail analysis of the lake water at different seasons including other quality parameters that are not included in the present study and to evaluate long term effects of drinking the water on different species, breeds and classes of livestock.