土壤中多环芳烃菲的自然降解特性

Natural degradation characteristics of polycyclic aromatic hydrocarbons phenanthrene in soil

自然降解是去除环境中有机污染物的一种重要手段.为了解土壤中多环芳烃的自然降解规律,选择陕北风沙滩地区风积砂为典型土壤,多环芳烃菲为典型污染质,探讨了菲在风积砂中的自然降解规律;建立了菲的降解动力学模型;进一步考察了污染浓度、温度、pH值、含氧量等环境因素对降解的影响.结果表明,风积砂中菲的自然降解符合准一级反应动力学,降解半衰期为17 d;菲的降解率与生物量呈正相关;污染浓度对菲的自然降解影响不显著;25 ～ 35℃、中性条件能够促进风积砂中菲的降解;好氧微生物是降解的关键,氧的存在对于土壤中菲的降解具有重要的作用.

Natural degradation plays an important role on removing the organic pollutants in the environ- ment. In order to understand the natural degradation law of polycyclic aromatic hydrocarbons（ PAHs） in soil, in this study, aeolian sand in blow-sand region of Northern Shaanxi was chosen as typical soil and phenanthrene （Phe） as typical pollutant of PAHs. The natural degradation law of Phe in aeolian sand was explored and degra- dation kinetics of Phe in aeolian sand was established. In addition, effects of initial Phe concentration, tempera- ture, pH and oxygen on Phe degradation were discussed. Results show that degradation law of Phe in aeolian sand follows pseudo first-order kinetics and degradation half-life of Phe is I7 days. Degradation rate and biomass are positive correlation. Initial concentration of Phe has no significant influence on natural degradation of Phe. Appropriate temperature between 25℃ to 35℃ and neutral condition can promote Phe degradation process in ae- olian sand. Aerobic microorganisms are key factor on degradation. The presence of oxygen plays an important role on the Phe degradation in aeolian sand.