南水北调东线工程及其调水特点对血吸虫病传播潜在影响的研究

Characteristics of engineering and diversion water and their potential effect on schistosomiasis japonica transmission in east route of South-to-North Water Diversion Project

目的了解南水北调东线第一期工程特点和水工建筑对血吸虫病传播的潜在影响。方法调查南水北调东线第一期工程布置情况,分析工程特点和水源调度方式对钉螺扩散和血吸虫病传播的影响;现场试验观察硬化河岸、"胸墙"、清(拦)污设施、水泵、消力池等水工建筑防螺作用。结果东线工程东平湖以南将建13级、共34座泵站;江都泵站引河硬化后已连续3年未查获钉螺;泵站前设置的拦污栅和清污机可有效拦截大部分漂浮物而使钉螺失去吸附载体;水泵内复杂的螺旋水流可使钉螺和吸附的漂浮物完全分离;泵站消力池水体可沉淀钉螺,水淹3、6个月钉螺死亡率分别达74%和98%;控制流速在0.2 m/s时,涵闸"胸墙"可完全拦阻漂浮物而有效防止钉螺扩散;东线工程水源由长江、淮河等组成,淮河枯水期多抽调江水,淮河丰水期多用淮水。结论南水北调东线工程布局特点、水源组成、调度方式及各级泵站和附设水工建筑均不利于血吸虫中间宿主(钉螺)北移扩散。

Objective To understand the characteristics of the engineering and diversion water and their potential effect on schistosomiasis japonica transmission in east route of the South-to-North Water Diversion Project. Methods The project layout of the first phase was surveyed in east route of the South-to-North Water Diversion Project. The engineering characteristics and regulation mode of water resources and their potential effect on snails and schistosomiasis spread were investigated and analyzed. The roles of the snail control of the hydraulic structures were observed and tested, and the hydraulic structures included the concrete bank, breast wall, the grid decontaminating apparatus press, the water pump and the stilling pool. Results There would be 34 pumping stations with 13 rundles on the south side of Dongping Lake in the first phase project of the eastern routes. There were no the snails for 3 year after the river dredging and concrete bank constructing in the diversion canal of the Jiangdu pumping station. The floating debris were intercepted maximally by the trash rack. The snails were separated from floating debris by the flow of spiral and nonuniform when the floating debris absorbed with snails passed through the water pump. The snails were precipitated in the stilling pool. The mortality of snails submerged for 3,6 months were 74% and 98% respectively. The floating debris absorbed with snails were intercepted completely by ＂the breast wall＂ of the sluice gates if the flow velocity was controlled at 0.2 m/s. Conclusion The project layout, regulation mode of water resources, pumping stations and other hydraulic structures will be of disbennifit to transmission towards north of snails and schistosomiasis in the east route of the South-to-North Water Diversion Project.