持久性有机污染物（POPs）六氯苯（Hexachlorobenzene，简称HCB）的有效降解是环境科学及生态学普遍关注的热点问题。基于本团队前期研究发现，人工湿地是一种能够高效降解HCB的生物处理方法，根际微生物降解是主要过程，但是HCB在人工湿地植物根际的降解机制及降解途径尚不清楚，从而限制了人工湿地在HCB污染防控中的应用。为此，本项目选择典型人工湿地植物普通芦苇和宽叶香蒲，构建湿地微宇宙系统，通过间歇式淹没法模拟不同溶解氧条件，研究HCB及其同系物在根际与非根际环境中的降解效能及其主要影响因子，并确定根系分泌物及根际微生物在HCB降解过程中的相对作用，进而依据降解中间产物的类型和浓度变化，确定HCB的生物降解途径，阐明HCB在人工湿地根际中的降解机制，以期探寻HCB污染防治的新途径。本项目将为HCB的高效降解提供理论依据和技术支持，也可为其它相关POPs的生物降解提供借鉴。

The effective degradation of Hexachlorobenzene (HCB) is a hot issue of common concern in environmental science and ecology. This project is based on our early results which indicate that constructed wetlands (CWs) can eliminate considerable amounts of HCB residues transported from agricultural fields and other potentially contaminated soil and rhizosphere microbial degradation is the main process.However, the lack of knowledge on degradation mechanism and degradation pathway of HCB in rhizosphere of CWs hampers the efforts to transfer phytoremediation results from labs to field sites. We plan to choose Phragmites australis or Typha latifolia as the typical macrophytes in CWs for mesocosms wetlands, investigate the reductive and oxidative dechlorination of HCB and its homologous compound in rhizosphere and non-rhizosphere and analyze the relative roles of dominant ecological factors, quantitative rhizosphere exudates and rhizosphere microorganisms in the process of HCB degradation by alternating cycles of flooding (to induce anaerobic conditions) and no-flooding (aerobic conditions) in mesocosms. Moreover, the chemical compositions and concentrations of dechlorinated products of HCB in rhizosphere soil and non-rhizosphere soil will be analyzed to elucidate the pathways of HCB dechlorination under the action of rhizosphere effect, thus to reveal the HCB degradation mechanisms for controlling HCB in the future. The project will provide possible solutions for high efficient degradation of HCB and serve as a reference for biodegradation of other related POPs (Persistent Organic Pollutants).