Abstract: We investigated plant species composition of a heavily mercury (Hg) contaminated wasteland composed of cinnabar ore mine tailings in Wanshan. We measured the concentrations of total mercury (THg) and methylmercury (MeHg) in both plants and rhizospherc soils and analyzed the bioaccumulation and transfer factors of IHg (the difference between THg and MeHg) and MeHg in plants. Results showed that the concentration of THg in soils ranged from 3.1 to 479 mg·kg^-1, indicating a heavy Hg contamination. Plant community composition of wastelands varied widely, with Compositae as the dominant species, accounting for 6.4% of the total. The concentrations of IHg in roots and shoots of plants ranged from 0.59-3.3 and 0.27-12 mg·kg^-1, respectively. Aster ageratoides exhibited the highest values of IHg in both roots and shoots, reaching 33 and 12 mg·kg^-1, respectively. The concentrations of MeHg in roots and shoots ranged from 0.56-5.6 and 0.24-22 μg·kg^-1, respectively. Sonchus arvensisshowed the highest average values of 22 μg·kg^-1 MeHg in roots and 5.6 μg·kg^-1 MeHg in shoots. Bioaccumulation factors (BFs) of IHg in plants were less than 1, while the BFs of MeHg in Sonchus brachyotus and Aster ageratoides were greater than 1. For transfer factors (TFs), Aster ageratoides andBuddleja lindleyana exhibited the highest TFs in IHg and MeHg with values over 1, suggesting their high ability in transferring IHg and MeHg.

Key words: Soil solution chemistry, Dissolved aluminum, Dissolved organic carbon Forest stand, Eco-chem-istry