变化径流下TCS和TCC在输水河流沉积物-水界面交换通量及机理研究

跨流域调水工程不可避免地改变了沿线输水河流的自然径流条件，对沉积物中污染物的迁移转化产生较大影响，然而现阶段对变化径流下沉积物-水界面污染物环境归趋的研究甚少，尤其是当前大量使用的抗菌剂，在变化径流下沉积物-水界面交换过程及环境响应机制尚不清楚。本课题拟以南水北调东线工程典型输水河流为研究区域，以三氯生（TCS）和三氯卡班（TCC）为研究对象，以被动采样技术为研究手段，研究TCS和TCC在枯水期、丰水期、平水期河流沉积物-水界面迁移扩散行为；研究沉积物-水界面上覆水和底泥孔隙水中目标物浓度分布，估算沉积物-水界面的交换通量强度及方向；探索变化径流条件对沉积物-水界面目标物交换过程的影响；阐明变化径流下TCS和TCC在沉积物-水界面的交换过程和环境响应机制；提出可减少污染物在沉积物-水界面交换通量的防控途径，为科学评估调水工程对水环境的影响和保障输水水质安全提供理论和科学依据。

The inter-basin water diversion project inevitably changes the natural runoff mode of water-conveying rivers along the line, which has great impacts on the migration and transformation of contaminants in sediments. However, current studies focusing on the environmental fate of contaminants at the sediment-water interface of water-conveying rivers under changing runoff conditions are still sparse. In particular, the exchange process of widely used antibacterial agents at the sediment-water interface and environmental response mechanism are still unclear. This study plans to be carried out in the typical water-conveying rivers in the east line of South-to-North Water Transfer Project, and to select Triclosan (TCS) and Trichlorocarban (TCC) to investigate their migration and diffusion behavior using passive sampling technology, at the sediment-water interface of water-conveying rivers in dry, wet and normal seasons. Moreover, the concentration distribution of target substances in sediment-overlying water interface and sediment pore water will be investigated. The exchange flux intensity and direction at sediment-water interface will be estimated. Meanwhile, we will explore the effect of variable runoff conditions on the exchange process of the target object at sediment-water interface, and clarify the exchange process and environmental response mechanism for TCS and TCC at the sediment-water interface under changing runoff. The prevention and control measures are also proposed to reduce the exchange flux of contaminants at the sediment-water interface. The final result will provide theoretical basis and scientific grounds for scientifically assessing the impact of water diversion project on aqueous environment and for ensuring water quality safety.