Abstract

A study was conducted at Melka Hida and Wonji Gefersa farms where Awash River was used for cultivation of vegetable crops to assess heavy metal contamination of vegetables. To what extent these vegetables are contaminated is not known. Three leafy vegetable samples, namely, cabbage (Brassica oleracea Linn.), lettuce (Lactuca sativa) and spinach (Spinacea oleracea) from Melka Hida and Wonji Gefersa farms were examined for heavy metal (Cd, Cr and Pb) contamination using atomic absorption spectroscopy. The results indicate that the heavy metals in vegetables of Melka Hida farm were higher than those of the vegetables in Wonji Gefersa farm. In all the samples analyzed, the concentration of Pb and Cd was more than the maximum limit and their levels varied from 0.31 to 0.65 and 0.21 to 0.40 mg/kg, respectively. However, the level of chromium was generally within the normal range in cabbage (0.85 and 0.29 mg/kg) and spinach (1.30 and 1.06 mg/kg) from Melka Hida and Wonji Gefersa farms, respectively, except in lettuce from Melka Hida farm, 2.4 mg/kg. The high levels of these heavy metals place the consumers of these vegetables grown within the study area at health risk with time unless an urgent step is taken by relevant agencies to address this issue.

Key words: Awash River, contamination, trace elements, vegetables.