Determination of the level of heavy metals and assessment of their safety in cow's milk collected from Butajira and Meskan districts, south central Ethiopia.

Milk is a complete food useful to promote growth and development of the infant mammals as it contains vital nutrients (proteins, essential fats, vitamins, and minerals) in a balanced proportion. It is also a nutritious food for adults too. Milk can also contain hazardous chemicals and contaminants including heavy metals which can be a risk for health. This study was aimed at determining the level of heavy metals in cow's milk collected from Butajira and Meskan districts, south Ethiopia. Cows' milk was collected from 193 healthy lactating cows. Samples were digested by optimized microwave digestion method using HNO and HO. Analysis was done using ICP-OES for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn levels. MP-AES was used for Ca, Mg, K, and Na. Ni was not detected in all samples. Concentrations of heavy metals in the studied samples were Cd (0.0-0.03), Cr (0.0-0.4), Cu (0.03-1.1), Fe (0.0-1.9), Mn (0.0-0.7), Pb (0.0-12.3), Zn (0.0-8.2), Ca (380.1-532.4), Mg (159.6-397.9), K (1114.2-1685.8), and Na (495.9-1298.3) ppm. These values were compared with permissible values prescribed by different international organizations and available literatures. Cd, Cr, Cu, Mn, Pb, Zn, and Mg levels were found above the permissible limits. Thus, special attention needs to be given to the level of heavy metals in cows' milk, as they are difficult to remove from the body. Their accumulation to a level greater than their permissible limit could be deleterious to the health of the user.