Determination of heavy metal concentration in soils used for cultivation of Allium sativum L. (garlic) in East Gojjam Zone, Amhara Region, Ethiopia

Garlic is the most widely used bulb crop next to onion in Ethiopia. It has been used in many local peoples of Ethiopia as a flavoring agent in food and medicinal value for different diseases. The concentrations of eight heavy metals (Fe, Zn, Mn, Cu, Co, Ni, Cd, and Pb) in soil samples used for cultivation of garlic in East Gojjam Zone (Debre Markos, Dejen, Bichena, and Debre Werk) in Ethiopia were determined. The results obtained revealed that the mean heavy metal concentrations for Fe, Zn, Mn, Cu, Co, Ni, Cd, and Pb were 23,866-32,262 mg/kg, 137.1-213.4 mg/kg, 401.8-583.7 mg/kg, 52.1-77.3 mg/kg, 106.6-177.6 mg/kg, 87.5-123.5 mg/kg, 2.3-2.5 mg/kg, and 13.8-23.2 mg/kg, respectively. In general, the levels of metals in soil collected from all the sampling sites was found to decreased in the order of: Fe > Mn > Zn > Co > Ni > Cu > Pb > Cd. In general, the results reveal that the level of contamination of the soils by the heavy metals is not high at present and the soil is not polluted by toxic heavy metals (Cd and Pb). Therefore, the soils studied were not harmful for cultivation of garlic and other agricultural purposes.