鬼针草(Bidens pilosa L.)对镉污染农田的修复潜力

为探究富集植物鬼针草对镉(Cd)污染农田土壤的修复潜力,通过野外调查,原土盆栽试验和田间试验,测定鬼针草及其根系土壤Cd含量,计算鬼针草的富集系数和去除率。结果表明,野外调查中不同铅锌矿区生长的鬼针草叶片中Cd含量最大值为53.3 mg/kg。盆栽试验中,低浓度Cd土壤处理(T1),鬼针草地上部Cd的富集系数为4.70,转运系数1.59,大于1。高浓度Cd土壤处理(T2 13.4 mg/kg),其地上部Cd积累量达到43.1 mg/kg,其地上部Cd富集系数为3.51。鬼针草对Cd表现出稳定的积累特性。田间试验小区中,土壤Cd含量均值为2.66 mg/kg,鬼针草中地上部Cd含量均值为10.9 mg/kg,富集系数为4.16,使用鬼针草修复Cd污染土壤每公顷地种植一茬鬼针草的去除率为4.3%—6.2%。使用富集植物鬼针草修复农田Cd污染具有较好的工程应用前景。

Remediation Potential of B. pilosa L. in Cadmium-Contaminated Farmland

The potential of remediation of cadmium (Cd)-contaminated farmland soil by enrichment of the plant B. pilosa L. was explored by determination of Cd content in the soil and at the root-soil interface through field investigation, soil pot experiments, and field experiments, and the bioaccumulation factor and removal rate of vetiver were calculated. Field investigation of the growth of the B. pilosa L. in mines sites of four provinces revealed a maximum Cd content of 53.3 mg/kg. In the pot experiments with a low concentration of Cd in soil treatment (T1), the B. pilosa L. Cd bioaccumulation factor was 4.70 and the translocation factor was 1.59 (greater than 1); with a high concentration of Cd in soil treatment (T2 13.4 mg/kg), the aboveground Cd accumulation reached 43.1 mg/kg, and the aboveground Cd bioaccumulation factor was 3.51. B. pilosa L. showed stable accumulation of Cd. In the field test plot, the average content of Cd in soil was 2.66 mg/kg, the average content of Cd in the upper part of the field was 10.9 mg/kg, and the enrichment coefficient was 4.16. The removal rate by B. pilosa L. was between 4.3% and 6.2%. Thus, B. pilosa has good potential for use in engineering applications to resolve Cd pollution in farmland.