Preliminary results of the tolerance to inorganic contaminants and phytoextraction potential of twelve ornamental shrub species tested on an experimental contaminated site

摘要

In urban areas of China, several plant species are commonly used for ornamental purposes. Many of these plants have demonstrated a good capacity to resist these varied urban stresses, and it would be relevant to verify whether they can be grown on polluted sites and demonstrate some phytoremediation potential. Twelve ornamental shrub species were chosen to be tested for tolerance to inorganic contaminants and capacity to absorb and concentrate heavy metals in their aerial parts. A large split-plot trial comprising 20 plots was set up, and soil was spiked with different metals (Cu, Pb and Zn). In general, all twelve shrub species performed well regardless of the treatment. Two Hibiscus species, H. mutabilis and H. syriacus “Hamabo” were particularly productive. In terms of capacity to uptake metals, two of the best performing species were Spiraea japonica, for copper, and Nandina domestica, for lead. Bioconcentration and transfer factors were low. This could be related to weak development of the root systems in these recently established plants. Species with high yield, such as the two Hibiscus species, presented more interesting values in terms of quantity of metal extracted, and could eventually be recommended for decontamination of soils polluted by inorganics.