African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6652

Full Length Research Paper

Levels of some toxic heavy metals (Cr, Cd and Pb) in selected vegetables and soil around eastern industry zone, central Ethiopia

Dagne Bekele Bahiru
  • Dagne Bekele Bahiru
  • Debre Zeit Agricultural Research Center, Debre Zeit, Ethiopia.
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Endale Teju
  • Endale Teju
  • Department, Faculty of Natural and Computational Science, Haramaya University, Haramaya, Ethiopia.
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Tesfahun Kebede
  • Tesfahun Kebede
  • Department, Faculty of Natural and Computational Science, Haramaya University, Haramaya, Ethiopia.
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Negash Demissie
  • Negash Demissie
  • Debre Zeit Agricultural Research Center, Debre Zeit, Ethiopia.
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  •  Received: 13 June 2018
  •  Accepted: 13 July 2018
  •  Published: 10 January 2019

Abstract

The purpose of this study was to determine the concentration of heavy metals (Cr, Cd and Pb) in vegetables and the soil contaminating levels as a result of irrigation using Flame Atomic Absorption Spectrophotometer (FAAS). The wet digestion and sequential fractionation extraction procedures were employed to solubilize the metals from the collected samples. The results obtained from this study showed overall concentration of heavy metals Cr, Cd and Pb respectively, in the range of (2.90-3.77), (2.20-3.68) and (4.60-5.50) (mg/Kg) in the edible parts of sampled vegetables. Whereas, concentrations (mg/Kg) of the metals in the soil samples were found to be in the ranges of 22.37-66.30, 27.93-45.33 and 18.82-64.87 for Cr, Cd and Pb, respectively. The modified Tessier sequential extraction procedure was used to fractionate the above three metals from the soil samples into five fractions. In this study the heavy metals were predominantly concentrated in residual fraction (F5); since lead was mainly associated with the organic matter bounded fraction (F4) (34.33-43.45%), it was found to be more bioavailable and mobile than the other investigated heavy metals. The concentrations of heavy metals (Cr, Cd and Pb) in the soil and vegetable samples were above the recommended limit of both WHO and FAO. But Pb for the soil samples was smaller than WHO and FAO recommended limit. Based on facts obtained from this study we suggests concerned official body (ies) to take the necessary precaution measures for cleaning the polluted area.

Key words: Heavy metals, sequential fractionation, eastern industry zone.