河道底泥中微塑料与重金属共存所造成的复合污染是当前亟待面对与深入研究的环境热点问题，本项目拟围绕河道底泥-微塑料-重金属界面交互作用关系、微塑料与重金属在河道底泥中的协同污染机制两大关键科学问题开展研究。项目将首先探讨底泥对微塑料的老化规律，探究底泥主要矿物成分在微塑料表面的粘附机理，分析底泥、矿物相组分以及老化前后微塑料等对重金属的吸附行为，从分子结构层面深入探讨微塑料及其表面所粘附的矿物成分与重金属的结合机制，明晰重金属在底泥和微塑料之间的分配行为；其次，项目将分别选取自然水体和模拟动物消化液等不同场景，分析吸附后的底泥和微塑料表面重金属解吸行为，探讨底泥影响下微塑料与重金属复合污染物的协同释放机制。通过上述研究，项目将揭示河道底泥、微塑料、重金属三者之间的界面微观交互作用机理，明晰河道底泥中微塑料与重金属的协同污染行为，为内陆河流体系微塑料与重金属的复合环境效应研究提供理论依据。

The coexistence of microplastics and heavy metals in the river sediment has become one of the most pressing environmental issues, and a systematic research is urgently needed on the consequential pollution. This project intends to study the interfacial interactions among river sediment, microplastics, and heavy metals. Moreover, a mechanism study is also to be conducted on the sediment pollution caused by a combination of microplastics and heavy metals. The aging of microplastics in the river sediment will be investigated, with a further explication on the mechanisms of the minerals attachment to the microplastics surface. The adsorption behaviors of heavy metals will be examined on river sediments, minerals, as well as microplastics before and after aging. Furthermore, the metal adsorption mechanisms will be explicated based on a deep analysis of the mineral speciation on the microplastics surface and their interactions between the heavy metal ions. The effects of microplastics type, size as well as surface morphology on metal adsorption will be further discussed. Moreover, a competitive adsorption will be conducted between the sediment and different types of microplastics, with the purpose to quantify the heavy metal distribution on the surface of different materials. In addition, the heavy metal desorption will also be carried out in the natural water environment and the simulated intestinal fluids, aiming to explicate the synergistic effects of combined pollution by microplastics and heavy metals in the river sediment. Therefore, by conducting extensive experiments and intensive analysis using a series of advanced techniques, this study will clarify the interfacial interactions among river sediment, microplastics and heavy metals, which can greatly help to narrow the knowledge gap in environmental issues caused by microplastics and heavy metals in inland river systems.