贵州万山汞矿废弃地自然定居植物对汞与甲基汞的吸收与累积

Distribution of inorganic mercury and methylmercury in wild plants inhabited on abandoned lands of Wanshan Hg mining region,Guizhou Province

以万山汞矿废弃地为研究区域,调查植物种类分布特征,分析植物和根际土壤总汞与甲基汞的含量,并探讨不同植物对无机汞(IHg)和甲基汞(MeHg)的富集能力和迁移能力。结果表明:汞矿区废弃地土壤总汞含量变化范围为3.1～479 mg·kg^(-1),汞污染十分严重;不同废弃地自然定居植物组成差异较大,以菊科居多,占所有植物的6.4%。植物根部IHg变化范围为0.59～3.3 mg·kg^(-1),地上部为0.27～12 mg·kg^(-1),其中根部和地上部IHg含量最高的植物是三脉紫菀,分别为33和12 mg·kg^(-1)。植物地上部与根部MeHg含量分别为0.56～5.6和0.24～22μg·kg^(-1),其中苣荬菜无论根或地上部都显示了最高甲基汞含量,分别为22和5.6μg·kg^(-1)。从富集系数(BFs)而言,所有植物根部和地上部对IHg呈现较低的富集能力,BFs均小于1;地上部和根部对MeHg富集能力较高的植物分别是三脉紫菀和苣荬菜。从转移系数(TFs)而言,对IHg和MeHg转移系数最高的分别是三脉紫菀和大叶醉鱼草。

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 479mg·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,reaching 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^-1MeHg in roots and 5.6 μg·kg^-1MeHg 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 Me Hg with values over 1,suggesting their high ability in transferring IHg and MeHg.