The study was undertaken to determine toxic heavy metals: cadmium (Cd), lead (Pb), arsenic (As) and chromium (Cr) in livestock feed, livestock water and cow milk in West Shoa zone (Holetta area) and East Shoa zone (Akaki-Mojo) Ethiopia. A total of 90 feeds, water and milk samples were collected from the study areas. Quantification of heavy metals was determined using Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS). Results showed that the concentrations of heavy metals in teff straw in Holetta and Bishoftu were 1543.54 Â± 318.70 Î¼g/kg and 1486.92 Â± 279.73 Î¼g/kg respectively. The overall concentration of heavy metals in teff straw in the study locations was in the order Cr > As > Pb > Cd. The concentrations of heavy metals in livestock water in Bishoftu (28.08 Â± 7.02 Î¼g/L) was significantly higher (p<0.05) than the concentration of water collected from Holetta (1.96 Â± 0.28 Î¼g/L) and the levels in both study locations were in the order Cr > As > Pb > Cd. Water sample from Modjo Tannery had the highest concentration of heavy metals (86.89 Î¼g/L) followed by Mojo Lake (67.89 Î¼g/L) and a river near Mojo town (43.64 Î¼g/L). With the exception of pH of water from Mojo Lake (10.37) and Gelan dye factory (8.9), the rest of water samples collected from Eastern shoa were within the recommended pH limit of 6.5-8.5 for livestock drinking. All water samples collected from Holetta had an average pH of 7.0 ranging 6.4â€“7.7 and were within the permissible limit. The overall concentration of heavy metals in cow milk in the study locations were in the order Cr > Cd > Pb > As. The concentrations of Cd and As in milk in both study locations were within the permissible limits. However, the concentrations of Pb in 60% (Holettasâ€™milk samples) and 73% (Bishoftusâ€™ milk samples) and the concentration Cr in all milk samples were above the permissible limit which is an indication of environmental pollution. This preliminary study showed elevated concentrations of Cr and As in teff straw in both study locations suggesting the need of further investigation of heavy metals from soil samples and feeds.
Keywords: Lead, Cadmium, Chromium, Arsenic, teff straw, Holetta, Bishoftu