黑碳对水体沉积物中微生物降解壬基酚的影响与作用机理研究

Nonylphenol (NP) is a kind of endocrine-disrupting contaminants (EDCs) and hydrophobic organic contaminants (HOCs) in the environment, and 60% of NP in the environment exists in the sediment. Black carbon (BC) is a promising novel material of controlling HOCs and an important part of organic matter in the sediment, whose super adsorptivity could reduce the bioavailability of HOCs. Many previous researches were conducted in short-term degradation experiments under low HOCs concentration, and the results demonstrated that BC could suppress the degradation of HOCs. But in fact, BC could increase the microbial degradation of HOCs by lowering the acute toxicity of HOCs as well as promoting the growth of microbe and biological membrane, when the concentration of HOCs is relatively high. Therefore, based on the above, we propose a project which aims NP as the research object. After understanding the sorption-desorption behavior of NP to BC, a series of experiments will be conducted to investigate the influence of BC on the growth of microbe in natural sediment and the degradation of NP, examine the influence of BC on the existing forms and the degradation of NP, establish the biodegradation- desorption coupling model for NP, and then explore the mechanism of the influence of BC on the NP degradation. Consequently, it is expected that this project will clarify the effect of BC on the degradation of NP in sediments as well as on the long-term fate of HOCs, evaluate the feasibility of the application of BC on the HOCs pollution, and provide theoretical foundation for remediation of HOCs pollution in water environment in our country.

壬基酚（NP）是目前典型的环境内分泌干扰物和疏水性有机污染物（HOCs），环境中60%的壬基酚分布于沉积物中。黑碳是颇具前景HOCs控制的新型材料，也是沉积物有机质的重要组成部分，其超强的吸附性能会降低HOCs的生物可利用性。大量学者开展了较低HOCs浓度下短期降解实验，得出了黑碳抑制HOCs降解的结论。实质上在较高HOCs浓度下，黑碳可能会通过降低急性毒性，促进微生物生长和生物膜形成来加速HOCs降解。基于此，本项目提出以NP为对象，在研究黑碳对沉积物中NP的吸附-解吸特性的基础上，拟研究黑碳的存在对自然沉积物体系中微生物生长及NP降解的影响；分析黑碳作用下NP形态分布与降解的相关性，建立吸附-降解耦合模型，探讨黑碳对NP降解的影响机理。以期阐明黑碳对沉积物中HOCs微生物降解及长期归趋的影响，探讨将黑碳应用于HOCs修复的可行性，为水环境中HOCs的污染控制与原位修复提供理论依据。

本研究以典型环境内分泌干扰物壬基酚为目标污染物，探讨了沉积物黑碳在疏水性有机污染物（HOCs）微生物降解过程中的作用及其对HOCs长期归趋的影响。项目从钱塘江流域壬基酚污染现状调研出发，研究了新鲜黑碳-沉积物、老化态黑碳-沉积物等体系对壬基酚的吸附-解吸特性及其机理，建立了吸附性能随黑碳含量与老化时间变化的预测模型。在吸附研究的基础上，以自然沉积物体系、壬基酚降解的富集培养体系和纯培养三个体系为手段，一方面证实了适量黑碳的添加可通过降低壬基酚对微生物的毒性效应而促进污染物的降解；另一方面，通过TENAX解吸动力学探讨了壬基酚的吸附形态与降解活性之间的相关性，运用同分异构体探讨了黑碳对壬基酚降解结构选择性的影响。在此基础上，探讨了将黑碳应用于沉积物/土壤中HOCs原位修复的可行性。研究结果阐明了沉积物黑碳对HOCs归趋的影响、丰富了有机污染物的吸附-降解理论，也为后续沉积物/土壤中HOCs的污染修复技术的研发奠定了基础。