Heavy Metal Accumulation of 13 Native Plant Species Around a Coal Gangue Dump and Their Potentials for Phytoremediation

摘要

This study was designed to investigate the heavy metal accumulation characteristics of 13 native plant species and associated rhizosphere soils around Taoyuan coal gangue dump, and to determine their potentials for phytoremediation. The mean concentrations of Cu, Cd, Pb and Cr in rhizosphere soils were 46.70, 0.43, 16.86 and 109.67 mg·kg -1 , respectively. According to the pollution load index, the soils were strongly contaminated by Cd, moderately contaminated by Cu, slightly contaminated by Cr and uncontaminated by Pb. The concentrations of Cu, Cd, Pb and Cr in shoots of the 13 plant species ranged as 1.86-33.10, 0.10-0.94, 2.04-14.72 and 0.49-9.03 mg·kg -1 , respectively, while in roots ranged as 0.44-91.56, 0.31-1.82, 4.83-50.49 and 0.37-99.63mg·kg -1 , respectively. No plant species satisfied the concentration criteria of hyperaccumulator, but two high Cd-enriched species of M. falcata and C. japonicum, whose BCF and TF values were all greater than one, were recorded. Based on the Individual Phytoremediation Factors (IPF), S. viridis showed the strongest remediating capability per a single plant for Cu, while M. falcata, S. viridis, C. eragrostis and C. japonicum had relatively strong remediating capability per a single plant for Cd. The four plant species were proposed to be preferentially taken as the candidates for phytoremediation.