长江流域水生态环境安全主要问题、形势与对策

为进一步深化长江流域水生态环境保护的系统性、整体性科学认识，围绕长江水生态环境安全的主要问题及形势进行了剖析，提出了进一步加强长江流域水生态环境安全保障的对策建议.研究表明:在水环境质量方面，磷污染成为制约水质改善的主要影响因素，农业源排放量占比高，但工业源入河对水体的影响更直接，水库群运行带来的水沙条件变化对磷污染沿程演变有明显影响；在水生态健康方面，长江水生生物资源衰退、湖库富营养化格局发生改变、湿地生态功能退化问题突出；在水环境风险方面，化工围江、航运污染风险引起广泛关注.当前长江流域面临着源头区水资源战略储备减少、区域经济发展与生态环境保护双重压力仍较大、水环境质量仍存问题隐患、水生态系统退化态势未得到根本遏制等复杂且严峻的形势，未来长江水生态环境安全保障仍有诸多挑战.建议统筹长江全流域“一盘棋”，推进区域绿色协调发展，强化磷污染点面源综合管控，着力提升水生态健康水平，同时加快水环境风险隐患排查整治，强化科技创新有效供给. 

Main Problems, Situation and Countermeasures of Water Eco-Environment Security in the Yangtze River Basin

In order to have a in-depth and holistic scientific understanding of the eco-environment protection in the Yangtze River Basin, the main problems and status of the Yangtze River's water eco-environment security were analyzed, and countermeasures and suggestions for further strengthening the water eco-environment security in the Yangtze River Basin were proposed. The research indicated that in terms of water environment quality, phosphorus pollution has become the main factor restricting the improvement of water quality. Agricultural sources account for a large portion of the total phosphorus pollution, but industrial sources entering rivers have a more direct impact on the water bodies, and the changes in water and sediment conditions caused by the operation of the reservoir group have a significant impact on the evolution of phosphorus pollution along the mainstream of the Yangtze River. In terms of water ecological health, the aquatic biological resources in the Yangtze River are declining, the eutrophication pattern of lakes and reservoirs is changing, and the ecological functions of wetlands are degraded. In terms of water environmental risks, the pollution risks of the chemical industry along the river and shipping industry have aroused widespread concern. At present, the Yangtze River Basin is facing complex and severe situation, including the decrease of the strategic reserve of water resources in the source area, the dual pressures of regional economic development and eco-environmental protection, and the hidden risks of the problems in the water environment quality. In the future, the eco-environment security of the Yangtze River still faces many challenges. It is recommended to coordinate the 'one game of chess' in the entire Yangtze River Basin, promote regional green coordinated development, strengthen the comprehensive management and control of point and non-point sources of phosphorus pollution, focus on improving the water ecological health, accelerate the investigation and remediation of the hidden risks in the water environment, and strengthen the effective supply of technological innovation.