高羊茅对土壤中菲、芘污染的修复机制研究

采用盆栽试验法,研究高羊茅对土壤中芘、菲的去除效果与修复机制.结果显示:试验浓度范围(0~322 mg.kg-1)内,高羊茅能在芘、菲污染土壤中正常生长,且对污染物有较好的去除效果.种植高羊茅70 d后,菲、芘去除率分别为52.82%~83.28%、47.27%~75.39%;平均去除率分别比对照1(加0.1%NaN3)高63.04%、57.48%,比对照2(无NaN3)高45.59%、41.8%.修复植物也具有一定的积累作用,根部、茎叶部积累量随土壤中菲、芘含量增加而增大;生物浓缩系数则随菲、芘含量增加而减小,且根部大于茎叶部、芘大于菲.修复过程中,非生物因子、植物积累、植物代谢、微生物降解对菲去除的贡献率分别为5.1%、0.29%、3.42%、17.47%,对芘去除的贡献率分别为2.56%、1.87%、3.4%、15.68%;植物—微生物间的交互作用对菲、芘去除的贡献率则高达41.88%和36.54%.说明植物—微生物交互作用是土壤中菲、芘去除的主要原因.

Repair Mechanism Research on Pollution of Phenanthrene and Pyrene by Tall Fescue in Soil

Micropot experiments were carried out to investigate the mechanisms of the removal and accumulation of phenanthrene（Phe） and pyrene（Pyr） by tall fescue（Festuca arundinacea）.The results show that the growth of tall fescue is not affected by Phe or Pyr at their initial concentrations of 0 to 322 mg·kg^-1 in soils and it can significantly remove polycyclic aromatic hydrocarbons（PAHs） from soils.After 10 weeks plantation,the extractable PAHs are lower in planted soils than those in unplanted soils.52.82%～83.28% of Phe or 47.27%～75.39% of Pyr are removed from the soils,respectively.Tall fescue removes averagely 63.04% of Phe or 57.48% of Pyr from the soils as compared to CK1（with addition of 0.1% NaN3）,and 45.59% of Phe or 41.8% of Pyr as compared to CK2（without NaN3）.Tall fescue shows some ability to accumulate PAHs from the soils,the contents of PAHs in its root and shoot increase with the increase of PAHs concentrations in the soils.The bioconcentration factors（BCFs） for PAHs tend to decrease with increasing concentrations of these contaminants in soil,the BCFs for Pyr are higher than those for Phe,and the BCFs for Phe（0.08～0.89） or Pyr（0.66～3.73） in shoots are much lower than those in roots（0.24～2.78 and 1.4～11.59） at same treatment.Despite the plantation of tall fescue evidently enhanced the remediation of PAHs in soils,contributions of biotic and abiotic factors to phytoremediation process display distinct diversity.Abiotic loss,plant accumulation,phytodegredation and microbial degradation account for 5.1%,0.29%,3.42% and 17.47% of the total removal of Phe,and 2.56%,1.87%,3.4% and 15.68% of Pyr from soils,respectively.In contrast,41.88% of the total removal of Phe or 36.54% of Pyr is attributed to the contributions of plant-microbial interactions.Thus plant-microbial interactions are the main mechanisms for the remediation of soil PAHs pollution.