冷水江锑矿废弃地乡土树种重金属富集能力研究

采集并分析了冷水江锑矿区废弃地乡土树种及其根际土壤重金属含量,研究了树种对重金属的富集和转运特征。结果表明:矿区废弃地土壤中Cd含量超出国家土壤污染风险筛选值(GB 15618—2018),Sb含量是全国土壤背景值的104~226倍,以Cd、Sb重污染为主,伴有As、Hg、Pb复合污染。采集的8种乡土树种均对重金属元素表现出一定的耐受性,柏木、楸树对Hg、Cd和Sb的富集与运转能力较强;构树对Pb、Hg、Cd和Sb的富集与运转能力较强;南酸枣对Hg、Cd和Sb富集能力强,Cd、Sb运转能力较弱;七里香、梓树、棕榈和大叶女贞对Hg、Cd富集与运转能力强。根据废弃地重金属污染情况与树种对重金属的富集系数、运转系数,得出柏木、楸树、南酸枣和构树适合作为锑矿区废弃地植物修复的优选树种。

Study on Heavy Metals Enrichment Characteristics of Native Tree Species at Antimony Mine Area in Lengshuijiang

Contents of heavy metals in native tree species and their rhizosphere soils at antimony mining area wasteland in Lengshuijiang were collected and analyzed.Plant’s ability to enrich and transport heavy metals was investigated.The results show that soils in mining area wasteland are highly contaminated by Cd and Sb accompanied with combined pollution of As,Hg and Pb.Cd concentration surpasses national soil pollution risk screening value(GB 15618—2018),while Sb concentration is 104-226 times of soil background value of heavy metals in China.Eight native plants show tolerance to contamination.Catalpa bungei and Cupressus funebris have highest plant’s ability to enrich and transport heavy metals of Hg,Cd and Sb.Broussonetia papyrifera has high plant’s ability to enrich and transport heavy metals of Pb,Hg,Cd and Sb.Choerospondias axillaris has high plant’s ability to enrich heavy metals of Hg,Cd and Sb,and lower plant’s ability to transport heavy metals of Cd,Sb.Murrayapaniculata,Catalpa ovata,Trachycarpus fortunei and Ligustrum lucidum have higher plant’s ability to enrich and transport heavy metals of Hg,Cd.According to pollution of heavy metals in wasteland,and enrichment and transport coefficient of heavy metals by plant,Cupressus funebris,Catalpa bungei,Choerospondias axillaris and Broussonetia papyrifera are sellected as preferential species of phytoremediation of antimony mining area wasteland.