Heavy metal uptake by wheat from a sewage sludge-amended calcareous soil

摘要

The objective of this 4-year study was to determine single and repetitive effects of sewage sludge applications on the accumulation of lead (Pb), cadmium (Cd), zinc (Zn) and copper (Cu) in soil and wheat (Triticum aestivum). A single sludge application at a rate of 100 Mg ha−1 (for all the metals) and at a rate of 50 Mg ha−1 (for Cu) significantly increased DTPA-extractable metal concentrations 4 years later. DTPA-extractable concentrations of Pb, Zn and Cu were closely correlated with the total concentrations in soil. Their relationships between metal uptake in stalks and DTPA-extractable metal concentrations in soil were approximately linear for Pb, Cd and Cu, but better described by a quadratic equation for Cd and Zn. TF for Pb, Zn and Cu, BF for all metals and BCF for Pb, Cd and Zn were lower in wheat grown on sludge-treated than control plots.