Study Of The Inorganic Nitrogen Flux Into LaiZhou Bay From The Non-Point Pollution Sources In The XiaoQingHe Basin

The red tides of LaiZhou Bay always take place in the regions where the inorganic nitrogen concentration is higher than other ones. The inorganic nitrogen from XiaoQing River watershed is the main input source of Laizhou Bay. With carrying on the protection projects, the non-point pollution becomes one of the major reasons of the inorganic nitrogen pollution of the XiaoQing River Basin. Therefore, it is necessary to establish a model to precisely evaluate and calculate the flux into sea from XiaoQing River Basin in order to control the red tides of LaiZhou Bay.In this dissertation it first collects the meteorological, hydrological, geological, soil and water quality data, investigates the composition of inorganicnitrogen(ammonia nitrogen nitrite nitrogen and nitrate nitrogen) pollution status inthe soil, water and silt of the main station in XiaoQing River and analyzes the annual and seasonal inorganic nitrogen concentration changes since 1984. Combining the research results of meteorological, hydrological and geological analyses and principles of hydrology, the forming mechanism of non-point pollution and the pollutant movement rules, it is established a non-point load model. The parameters of this model is adopted the serial observation data before 1996 to calculate and the data from 1996 to 1999 to confirm. The results show that these parameters are applicable. The concentration of the non-point contaminants is calculated by the regular observation data. Finally, it is used this model to calculate the total flux of the inorganic nitrogen into the sea from 1996-1999 in XiaoQing River Region, estimate the flux of the non-point sources into the sea and analyze the annual changes of the flux and the influence factors on the flux.The results show: the flux of the inorganic nitrogen from XiaoQing River Watershed into the sea has the obvious trend to increase. 1996-1999, the averageannual flux of inorganic nitrogen from non-point pollutions into LaiZhou Bay is 3436.73 tons and its proportion to the total flux of the inorganic nitrogen is 35.8 percent. The proportion of the flux of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen into LaiZhou Bay to the total flux the inorganic nitrogen from non-point pollutions is 90.1 percent, 7.1 percent and 2.8 percent, perspectively.