绿化树种对土壤多环芳烃含量的影响

Effects of Afforestation Species on Concentration of Polycyclic Aromatic Hydrocarbons in Contaminated Soils

利用盆栽试验方法,研究4种绿化树种对柴油污染土壤中多环芳烃(PAHs)含量的影响,开展修复后土壤PAHs潜在生态风险评价。结果表明:1年后栽培植物土壤中PAHs含量在L1,L2,L3水平下比对照分别降低50.6%,61.4%,43.9%,平均为51.9%,且在3～6个月内PAHs含量减少最快;PAHs组分中以苯并蒽、蒽、芘减少最多,分别达74.8%,69.6%,58.1%。不同树种对PAHs含量影响无显著差异。将平均效应区间中值作为警戒水平,计算得到PAHs的潜在生态风险可能性,结果显示L3污染水平下植物处理中PAHs组分芴、菲、芘的生态风险仍然很高,说明治理PAHs污染最根本的办法是控制PAHs的排放量。

Polycyclic aromatic hydrocarbons（PAHs） are a kind of organic pollutants which chronically remain in environments,and they are particularly concerned because some of them are potent toxic and can pose a carcinogenics risk to humans,and some can be highly persistent in the environment.The aim of this study was to investigate changes of PAHs contents in diesel-contaminated soils and to conduct a preliminary evaluation on the potential risk of residual PAHs after phytoremediation.The results showed that after one year PAHs concentration in the planted soils was reduced by 50.6%,61.4%,43.9% compared with the control and PAHs in the soils declined mostly rapidly from the third month to the sixth month regardless afforested land or not.BaA,ANT,PYR were mostly decreased in the planted soils.Four tested tree species all enhanced degradation of the chemicals.Sediment quality guidelines（SQGs）,developed for many potentially toxic substances,can be used to classify sediment samples with regard to their potential for toxicity,to identify contaminants of concern,and to prioritize areas of concern based on the frequency and degree to which the guidelines are exceeded.The calculated averages of the mean effect range median（MERM） were used to preliminarily evaluate the potential ecological risk of residual PAHs in the diesel-contaminated soils after one-year phytoremediation.The FLO,PHE,PYR in the planted soils in L3 exceeded 1.5 times of the values,indicating there existed the high ecological risk.Therefore,it is important to control PAHs pollution release.