Determination of heavy metal phytoavailability in contaminated soil and biosolids during phytoextraction using the DGT technique

摘要

The concentrations of heavy metals (Cd, Cu, Ni and Zn) determined by the DGT technique (C<,DGT>) and their concentrations in pore water (C<,SOL>) in contaminated soil and biosolids during phytoextraction were investigated to assess heavy metals phytoavailability. In the first 4 months of phytoextraction using 5 species of willow and poplar, C<,SOL> and C<,DGT> of heavy metals in phytoextracted biosolids decreased significantly compared to the control treatments. Salix reichardtii provided an exception, with C<,DGT> for Cd and Zn being higher in its phytoextracted soil and biosolids than in soil and biosolids for other species. Biosolids after 12 months of phytoextracted by S. reichardtii, its R values significantly increased for Cd, Ni and Zn but remained constant for Cu. These findings suggest that S. reichardtii takes up and actively mobilizes Cd, Ni and Zn and biosolids. These results agree with the metals accumulated in plant material. Whilst the concentrations of Cd, Ni and Zn in S. reichardtii leaves icreased significantly over time of the concentration Cu declined.