磁性炭基复合体对入湖河口沉积物中多环芳烃转化的影响及其作用机制

The polycyclic aromatic hydrocarbons (PAHs) pollution in the lake estuary has become more and more serious, which has a negative impact on the lake ecosystem, and even a threat to human health. Effective control and remediation of PAHs pollution in the estuary is particularly important for the lake water environment quality improvement. As a magnetic separation of electron acceptor, magnetic carbon-based composites are expected to develop into a new type of efficient and environmentally friendly in situ sediment remediation technology, but its exact mechanism have not been clearly clarified. The project proposed a new idea of examining the effect of microbial electromagnetic fields mediated by magnetic carbon-based composites on microbial community structure in sediments to elucidate PAHs transformation. The major factors controlling PAHs transformation and in situ PAHs transformation characteristics in the Zhihu Port and Dashui Port of Taihu Lake were investigated to clarify the characteristics of PAHs transformation process in the sediment mediated by magnetic granular activated carbon.The microbial metabolic processes, metabolites and magnetic effects with PAHs degrading bacteria directly using magnetic carbon-based composites as electron acceptor were analyzed. And the microbial community structure was analyzed by application of metagenomic technology to reveal the mechanism of the transformation of PAHs by magnetic carbon-based composites. The project has important application in environmental treatment and management of lakes, and also provides scientific guidance for the effective implementation bioremediation of contaminated environment.

湖泊河口区多环芳烃（PAHs）污染日益严重，对生态系统产生负面影响甚至威胁到人类的身体健康。有效控制和修复河口区PAHs污染，对湖泊水环境质量改善显得尤为重要。磁性炭基复合体作为一种可磁性分离的电子受体，有望开发成为一种新型高效及环境友好的沉积物原位修复工艺，但其机制尚未阐明。本项目提出了通过研究磁性炭基复合体介导下微生物电磁效应对沉积物中微生物群落结构影响来认知PAHs转化途径的一种新思路。项目将制备的磁性颗粒活性炭用于太湖河口区（直湖港、大水港），研究其介导下沉积物中PAHs转化过程特征及其主要的影响因素；且分析PAHs降解菌直接以磁性炭基复合体为电子受体的微生物代谢过程、代谢产物及磁效应；再应用宏基因组技术分析微生物电磁效应对微生物群落结构的影响，以揭示磁性炭基复合体对PAHs转化的作用机制。项目在湖泊环境治理和湖泊管理方面有重要的应用价值，为有效开展污染环境生物修复提供科学指导。

湖泊河口区多环芳烃（PAHs）污染日益严重，对生态系统产生负面影响甚至威胁到人类的身体健康。有效控制和修复河口区PAHs污染，对湖泊水环境质量改善显得尤为重要。项目研究了磁性炭基复合体介导下入湖河口沉积物中PAHs的转化过程及作用机制。其主要创新成果包括解析了湖湾区沉积物微生物群落结构与功能对PAHs污染的响应特征及反馈机制，当湖湾生态系统受到PAHs污染时，其表层和次表层沉积物中微生物群落呈现自发适应、自发组装模式以响应外界环境干扰，关键物种协调指挥着核心菌群去执行生态系统的修复功能；沉积物微生物群落的组装模式及功能响应特征表明，河流沉积物微生物群落可以自发的组装或者重构群落降解PAHs，而湖泊沉积物微生物群落需要生物刺激或者共基质的方式加快PAHs降解。阐明了磁性颗粒修饰的炭基复合体对有机污染物的吸附特征，发现磁化改性后降低了活性炭吸附苯酚的速率，但增加了生物炭的吸附速率，且吸附限速步骤主要为颗粒内扩散和边界层扩散，磁化改性后提高了炭基材料对毒物苯酚的饱和吸附量，磁性椰壳活性炭可以高效锁定水体中毒性有机污染物。揭示了磁性炭基复合体介导下入湖河口沉积物中PAHs分解转化特征，与常见的磁性炭基材料相比较，磁性丝瓜络生物炭可以显著促进沉积物中PAHs分解转化，磁性丝瓜络生物炭的这种转化作用与炭材料的良好导电特性密切相连；通过高通量测序等现代分子生物学分析手段，进一步揭示了磁性炭材料作用下沉积物中微生物群落的响应及组成特征，发现磁性丝瓜络生物炭处理组具有显著不同的微生物群落组成特征，其结构可以有效地富集能够降解PAHs的微生物菌种（Dehalococcoidia 、Dechloromonas、Anaerolineaceae等），这些优势菌种具有厌氧降解芳烃化合物的功能属性。这些研究成果为PAHs 污染沉积物的原位修复技术提供重要的理论支持。