浅层孔隙地下水中石油烃生物降解的环境同位素研究

Contamination of groundwater by petroleum hydrogen is a chronic environmental problem across the globe. It is of concern due to its great harm and difficulty cleanup. MNA(Monitored Natural Attenuation) has extremely advantages, such as small environmental damage and economic costly, to remediate groundwater contaminated by petroleum products and other organic compounds. Biodegradation is the most important process for MNA as it removes contaminant mass. The acceptance of MNA for the management of contaminated sites requires a reliable technical basis to assess its performance at the field scale. Biodegradation is typically evaluated by monitoring changes in contaminant concentrations, electron acceptor distributions and biodegradation products along the plume flow path at contaminated site for MNA assessments. However, it can be difficult to distinguish abiotic processes from biodegradation. This will lead to series problems in evaluation works, such as poor reliability conclusions and multiple solutions. Therefore, in order to explore a new way to assess petroleum hydrogen biodegradation in aquifer, we select a petroleum contaminated site in Northeast of China, using a combination of environment isotopes, based on the analysis of water chemistry and microbiology , for assessment the petroleum hydrogen biodegradation. The objectives of this study are to explore the application methods of integrate several environmental isotopes that can improve description biodegradation of,petroleum hydrocarbons in groundwater and to estimate contribution rates of different biodegradation processes of hydrocarbons in polluted groundwater .

地下水石油烃污染因其污染普遍、危害性大、去除困难而备受关注。监测自然衰减修复技术（MNA）因其对环境破坏程度小、费用低等优势，成为了污染修复的研究重点。生物降解作用是地下水中石油烃自然衰减的主要过程，因此对其研究可为监测自然衰减技术实施的可行性提供重要依据。生物降解作用评估的典型方法是监测污染物、电子受体和降解产物浓度的时空变化。然而，由于非生物过程的影响导致了在微生物降解作用的评估中存在了诸多问题，例如评价结果准确性差和出现多个评价结果的问题。因此为了探索准确评估地下水中石油烃微生物降解作用的评价方法，本次以水化学和微生物学分析为基础，采用多种环境同位素联合应用的方法对东北某石油烃污染场地的石油烃微生物降解过程进行了研究，探索多种环境同位素在地下水石油烃微生物降解作用中的应用方法，并估算不同微生物降解作用对地下水中石油烃微生物降解程度的贡献率。

石油烃污染物自20世纪八十年代开始便被世界各国高度重视，并开展了一系列对地下水石油烃污染物的修复治理研究工作。在众多的修复方法中，微生物修复技术由于其依靠天然衰减能力、不产生二次污染物、对生态环境和土地利用的干扰程度较小、修复费用低等优势而受到国内外关注。生物降解作用评估的典型方法是监测污染物、电子受体和降解产物浓度的时空变化。然而，由于非生物过程的影响导致了在微生物降解作用的评估中存在了诸多问题，例如评价结果准确性差和出现多个评价结果的问题。.为了探索准确评估地下水中石油烃微生物降解作用的评价方法，本次以水化学和微生物学分析为基础，采用多种环境同位素联合应用的方法对东北某石油烃污染场地的石油烃微生物降解过程进行了研究，主要开展了如下工作：（1）调查分析了石油污染场地的水文地质和环境特征；（2）探索应用了多种环境同位素对地下水石油烃微生物降解作用进行识别，确定主要的降解反应机制为产甲烷反应和硫酸盐还原反应；（3）估算了不同微生物降解作用对地下水中石油烃微生物降解程度的贡献率，结果显示沿着污染晕延伸方向，产甲烷作用来源的无机碳比例由28.5~32.0%下降到 5.94~6.67%，在污染晕下游和边缘位置基本可以忽略。