3种草本凋落物混用强化修复石油污染土壤的效果

为明确凋落物混用对修复油污土壤效果的影响，以含石油质量分数15 g/kg的污染土壤为研究对象，分别加入质量分数2%的单种凋落物(胡枝子、铁杆蒿、黄蒿的凋落物)及3种凋落物的混合物(质量比为1∶1∶1)，在室温(20~25 ℃)、恒湿(饱和水质量分数50%)的条件下进行150 d的修复模拟实验。基于单种凋落物的处理结果及其在混合物中所占比例，计算混合物处理后污染物降解率以及土壤生化指标的理论预测值，并与实测值进行比较，以研究凋落物混用对土壤石油污染修复效果的影响。结果表明：凋落物混用强化了凋落物对土壤石油污染物的降解效果，使石油降解率比对应预测值提高了12.16%,其中饱和烃、芳香烃和非烃物质的降解率比对应预测值分别提高了14.43%、9.24%和10.52%；凋落物混用强化了凋落物对土壤漆酶和过氧化氢酶活性的刺激作用，但同时削弱了其对木质素过氧化物酶、蔗糖酶和多酚氧化酶活性的刺激作用,对土壤硝态氮的补充效果以及对土壤的酸化效应。

Improvement of the Remediating Effects on Petroleum Contaminated Soil Through Mixing Three Types of Herb Litters

To clarify how the mixing of litters affects their remediation effects on petroleum contaminated soil, litters from Lespedeza davurica, Artemisia gmelinii and Artemisia scoparia were added into petroleum contaminated soil (mass fraction of petroleum in soil 15 g/kg) individually with a mass fraction of 2% (litter/soil, dry mass), as well as their mixture in the proportion of 1∶1∶1. The litter amended soil was then incubated under the conditions of room temperature (20—25 ℃) and constant humidity (mass fraction of saturated water in soil 50%) for a 150 day remediation test. Based on the treatment results of each single litter and its proportion in the mixture, the theoretical predicted values of the contaminant degradation rate and the biological and chemical properties of the contaminated soil upon treatment by the mixture were calculated, and were then compared with corresponding observed values, so as to assess the effect of the mixing of litters on their remediation of petroleum contaminated soil. The results indicate that mixing of litters has improved their degradation of petroleum contaminants in soil. Specifically, the overall degradation rate of petroleum is increased by 12.16% as compared with the predicted value, and the degradation rates of saturated hydrocarbons, aromatic hydrocarbons and non-hydrocarbons are increased by 14.43%, 9.24% and 10.52% as compared with the corresponding predicted values; the mixing of litters has improved their stimulation on the activity of soil laccase and catalase, but weakened their stimulation on the activity of soil ligninperoxidase, invertase and polyphenol oxidase, supplementation to soil nitrate, and effects on soil acidification.