萝卜对土壤中全氟辛酸赋存形态影响及吸收特征

为探讨植物种植对土壤中全氟辛酸（Perfluorooctanoic acid,PFOA）赋存形态影响及吸收特征,以根系发达的萝卜为代表性植物,通过盆栽试验,探究了不同浓度PFOA污染土壤中萝卜的生长、对PFOA的吸收利用及土壤中PFOA形态分布的变化。结果表明：萝卜的种植会显著改变土壤中PFOA的赋存形态,且存在浓度差异。与无种植组相比,种植萝卜显著提高了低浓度土壤中的PFOA有机结合态比例（12%）、降低了残渣态比例（10.5%）;显著降低了高浓度土壤中PFOA的可脱附态比例（4.9%）。萝卜可从土壤中富集PFOA,且地上部（茎、叶）富集能力显著高于地下部。低浓度（0.2 mg·kg^-1）PFOA暴露显著降低萝卜生物量,但高浓度（5 mg·kg^-1）并未对生物量产生显著影响。研究表明,萝卜种植可以改变污染土壤中PFOA的形态分布,进而影响PFOA对人类健康及环境的潜在风险。

Effects of radishes on the speciation and absorption of perfluorooctanoic acid in soil

To understand the effects of radishes on the speciation and absorption of perfluorooctanoic acid(PFOA) in soil, a radish with a strong root system was chosen as a representative plant to study the growth and PFOA uptake of the radish, as well as the changes to the fraction distribution of PFOA in the soil under different concentrations of PFOA exposure in potted experiments. The results showed that radish planting significantly changed the speciation of PFOA in the soil, and this effects varied according to concentration. Compared with unplanted soil, radish planting significantly increased the non-desorbing fraction(12%) and reduced the residual fraction(10.5%) of PFOA in soil at low-PFOA exposure(0.2 mg·kg^-1), but remarkably reduced the desorbing fraction(4.9%) of PFOA in soil at high-PFOA exposure(5 mg·kg^-1). Radishes could uptake PFOA from the soil, and the concentrations of PFOA in the above ground part of the plant (stem and leaf) were significantly higher than those below ground. Low-PFOA exposure(0.2 mg·kg^-1) caused a decrease in radish biomass, while high-PFOA exposure(5 mg·kg^-1) had no significant effect on radish biomass. The results suggest that radish planting can change the fraction distribution of PFOA in the soil, and then influence its potential risks to human health and the environment.