Olsson, Mats
- Department of Soil and Environment, Swedish University of Agricultural Sciences
Abstract
Metal (Cd, Cr, Cu, Hg, Ni, Pb and Zn) and metalloid (As) status of two urban farms in Ethiopia were determined using the European Community Bureau of Reference (BCR) modified sequential extraction method. Cr, Ni, and As at Kera and Ni at Kolfe increased with depth likely due to leaching. Although total Cr, Ni (at both farms) and Pb (at Kera) exceeded normal limits, the bioavailability of these elements was restricted. Most of the trace elements at Kera (As, Cr, Cu, Ni, and Zn) and Kolfe (As, Cd, Cu, Ni, and Zn) were in residual fractions followed by reducible fractions. Pb at both sites was largely found in reducible form. Oxidizable and acetic acid extractable fractions were generally the least in proportion. Oxidizable Cr, Cu and Pb at both sites were higher than their acetic acid extractable counterparts, while acetic acid extractable Cd (at Kera) and Ni and Zn at both sites, exceeded the respective oxidizable metals. Bioavailability and toxicity of metals are sometimes reduced this way through natural means. However, change in soil pH, oxidation/reduction reactions, or similar mechanisms could cause shift in metal bioavailability. Hence, regular monitoring of the soil conditions at the farms is recommended.
Keywords
Bioavailability; leaching; sequential extraction; trace elements
Published in
African Journal of Agricultural Research
2008, volume: 3, number: 11, pages: 797-807
SLU Authors
UKÄ Subject classification
Agricultural Science
Permanent link to this page (URI)
https://res.slu.se/id/publ/22331