德兴铜矿区优势物种苎麻(Boehmeria nivea)对重金属的富集与积累特性

摘要

A study was conducted to investigate contents of three main heavy metal elements, cadmium, lead and copper, in ramie ( Boehmeria nivea) and its associated soils in the Dexing Copper Mining of Jiangxi Province. Samples of soils and ramie were collected from 8 sampling sites typical of the mining area for analysis. Results show that the soil of the area has been severely polluted with Cu and slightly with Cd, but not Pb, which was found still within the range of soil background values of Jiangxi Province. In the soils around the 8 sampling sites, the mean content of Cd, Pb and Cu was 0. 51, 9. 36 and 1058. 21 mg·kg-1 , respectively. In most of the sampling sites, the content of heavy metals was the lowest in ramie leaves and the highest in ramie roots, and the difference between the highest and lowest was drastic, reaching a few dozen times. In terms of bioaccumulation coefficient and transfer coefficient in the ramie, the content of heavy metals displayed an order of Cd>Pb> Cu. The heavy metals varied sharply in bioaccumulation coefficient and transfer coefficient in ramie. The highest bioaccumulation coefficient and the highest transfer coefficient of Cd was 1. 42 and 0. 54, of Pb 0. 63 and 0. 53, of Cu 0. 08 and 0. 37, respectively. Of the eight sampling sites, the mean biomass of ramie shoot was 1. 41 t·hm-2 , and the high-est reached to 2. 18 t·hm-2 . The mean bioaccumulation of Cd, Pb and Cu in the ramie was 0. 2, 1. 1 and 24 g·hm-2 , re-spectively. All the findings indicate that ramie is quite tolerant to Cu and Cd and can be grown as pioneer plant in mining ar-eas for control of heavy metals pollution and phytoremediation of the ecology in the area.%选取江西省德兴铜矿区8个采样点,对土壤和苎麻植株Cd、Pb和Cu含量进行测定分析.结果表明,铜矿区土壤中Cu污染严重并伴有轻微的Cd污染,Pb含量则在江西省土壤背景值范围之内.8个样点土壤Cd、Pb和Cu含量均值分别为0.51、9.36和1058.21 mg·kg-1.大部分样点苎麻植株叶片中重金属含量最低,根最高,最高值与最低值差距达数十倍,地上部重金属含量低于地下部.苎麻对上述3种重金属的富集系数和转运系数从大到小依次为Cd、Pb和Cu;苎麻对Cd的富集系数和转移系数最高值分别为1.42和0.54,对Pb的富集系数和转移系数最高值分别为0.63和0.53,对Cu的富集系数和转移系数最高值分别为0.08和0.37.8个样点苎麻的地上部生物量均值为1.41 t·hm-2,最高值达2.18 t·hm-2.苎麻对Cd、Pb和Cu的累积量均值分别为0.2、1.1、24 g·hm-2.因此,苎麻对Cu和Cd具有一定的耐性,在矿区种植苎麻可作为植物修复的先锋物种,促进矿区生态恢复.