Seawater Environmental Quality Assessment And Distribution Characteristics Of Main Pollutants In Maowei Sea Of Qinzhou

Maowei Sea is located the top of Guangxi Qinzhou Bay,possessing good natural water quality, and riching in resources of fisheries and shoal of coast.In recent years, intensive development of Maowei Sea, rapid growth of economy in neighbouring regions and the reclamation projects increased pressure to marine ecology. Extensive development mode such as hanging cultivation of oyster, raising economic fish species leads to the non-point source pollution in cultivation, the discharging of sediments and pollutants from River Qin and Maolingjiang weakened the water power, shallowed the sea area, tainted the sea water, and declined the water quality of Maowei Sea. Therefore, how to control water pollution, and alleviate ecological pressure effectively and protect the marine resources and environment is the urgent need of realizing the rational development and utility of sea area and sustainable development.In order to understand the water quality status of Maowei Sea, master the environmental quality status and trend of sea water and assess the water quality, this paper applied monitoring data and relevant economic data from Environmental Monitoring and Forecasting Center of Qinzhou Oceanic Administration.On the basis of single pollution factor evaluation, assessment of water quality grade, status of organic pollution and eutrophication of sea water. The results show that:1.The status of the water quality is poor in Maowei Sea which is belonging to heavy polluted sea area. Partial sea areas inferior to the fourth grade of national standard, the major pollutants were inorganic nitrogen, phosphate, and oil.2.As a whole, the seawater quality of inorganic nitrogen and active phosphate concentration of Maowei Sea area are in higher level and exceeded the standard seriously, especially the high value area in estuary area of Beibu Gulf. Besides, high value area of COD is concentrated on the area where three major rivers flow into the estuary of Beibu Gulf as well.3.Employing the Eutrophication index,according to the analysis,the average value of index is 7.99 in Maowei Sea which is belonging to heavy polluted sea area. Index of organics polluting showed that the average value of index is 4.49 in Maowei Sea which is belonging to middle polluted sea area.According to the main pollution factors to analysis the pollution sources and the space distribution characteristics of main pollution factors, explore the causes of pollution and potential risks of marine ecological environment. And then we put forward related suggestions about marine management and protection of environment, controlling land-based pollutants into the sea, monitoring the utility of ocean engineering, coordinating the relationship between marine cultivation and seawater environment in the process of development, utilization and protection in the future, which provides scientific basis for the sustainable development of Maowei Sea.