蜈蚣草对典型Hg矿区重金属的吸收和累积特征研究

Absorption and accumulation characteristics of heavy metals by Pteris vittata L. in typical Hg mining area

通过采集贵州省Hg、Cd、As、Pb和Cr复合污染的典型Hg矿区中生长的蜈蚣草(Pteris vittata L.)及其根际土壤,并利用蜈蚣草地上部分富集系数、地下部分富集系数及转移系数,探究了蜈蚣草对以上5种重金属的吸收和累积效果。结果表明:Hg矿区根际土壤中Hg、Cd、As含量存在超过《土壤环境质量农用地土壤污染风险管控标准(试行)》(GB 15618-2018)的现象,最大超标倍数分别达到81.5、2.5、3.1倍,Hg污染最严重。蜈蚣草地上部分重金属平均含量表现为As>Hg>Cr>Pb>Cd;地下部分表现为As>Cr>Hg>Pb>Cd。其中,地下部分重金属含量与根际土壤中重金属含量间存在明显正相关关系。蜈蚣草对As的富集能力最强,但As主要富集在蜈蚣草的地下部分,对地上部分影响较小。

Pteris vittata L.and its rhizosphere soil were collected to measure the contents of heavy metals.The absorption and accumulation characteristics of heavy metals were analyzed by up-ground accumulation factors,downground accumulation factors and translocation factors.The absorption and accumulation effects of Pteris vittata L.on heavy metals(Hg,Cd,As,Pb and Cr)in the typical Hg mining area with composite pollutions in Guizhou Province were explored.Results showed that the contents of Hg,Cd and As partially exceeded "Soil environmental qualityrisk control standard for soil contamination of agricultural land"(GB 15618-2018),of which Hg pollution was the most serious.The maximum excess times were 81.5,2.5 and 3.1 for Hg,Cd and As,respectively.The average contents of the up-ground parts of Pteris vittata L.showed As>Hg>Cr>Pb>Cd,and that of the down-ground parts did As>Cr>Hg>Pb>Cd.The heavy metals contents in down-ground parts of Pteris vittata L.positively correlated with that in rhizosphere soil,obviously.Pteris vittata L.had priority accumulation on As,but As were accumulated in the down-ground parts with little effects on the up-ground parts.