浅水风生波作用下再悬浮沉积物中磷释放的研究

Research on phosphorus release from resuspended sediment under wind-induced waves in shallow water

沉积物-水界面是湖泊的重要界面,与大多数环境和生态问题有关.风生波引起沉积物再悬浮造成水体二次污染.由于水、再悬浮沉积物和磷的耦合机制会影响界面附近磷的释放,因此探索了两种不同吸附解吸能力沉积物的耦合模型,以检查沉积物再悬浮后磷的释放规律.得到了风速、风生波特性、沉积物分布和水体含磷量之间的关系.风生波影响沉积物-水界面附近的局部流场,造成沉积物再悬浮.对于不同的沉积物,单位沉积物解吸释放量与风速呈负相关.中低风速时,沉积物因界面小范围流场变化再悬浮,上覆水中的磷快速增加,且难于扩散。此时,磷的释放表现出小范围集中释放的特点,可能迅速影响水环境,也可能为治理提供了窗口期。

Sediment-water interfaces are important interfaces for lakes,which are related to most environmental and ecological problems.Wind-induced waves cause secondary pollution via sediment resuspension.Since the coupling mechanism of water,resuspended sediments,and phosphorus affects the release of phosphorus(P)near the interface,a coupled model was explored for two sediment types with different adsorption-desorption capabilities to examine sediment resuspension and P release.The relationships among wind speed,wave characteristics,sediment distribution and P concentration were obtained.For different sediments,the unit sediment desorption release is negatively correlated with wind speed.When sediments are resuspended under low or moderate wind speed,the P concentration in the overlying water increases abruptly,hampering diffusion.P release exhibits the characteristics of concentrated release in a small region and changes the water environment rapidly.