Environmental Capacity And Carrying Capacity Of Main Pollutants In Daliaohe Estuary

As the junction of the sea and the land,there are frequent economic activities such as industrial development,ports,and shipping in Daliaohe Estuary.The seawater quality has been severely polluted,and the safety of marine ecology is threatened.For the sustainable development of marine functions,research on the environmental capacity and marine environmental carrying capacity of specific pollutants in the sea areas has increasingly become a hot spot for marine researchers.This paper selects three main pollution elements Chemical Oxygen Demand(COD),inorganic nitrogen and phosphate in Daliaohe Estuary to study the carrying capacity of the marine environment,provide technical support for protecting the marine environment of Daliaohe Estuary,preventing major risks of marine pollution,and achieving coordinated development of marine economy and ecology.Based on the functional positioning of "Liaoning Province Marine Functional Zoning(2011-2020)",this article focuses on the water quality management standards of 3 different types of functional areas in Daliaohe Estuary where 3 discharge outlets are located,and uses the water quality survey data in May 2019 as the current concentration,a two-dimensional hydrodynamic equation in the sea area of Daliaohe was established,and the conservative material diffusion equation was applied to the simulation process of the diffusion of three kinds of pollutants,the value method of the response concentration in a tidal cycle was optimized and determined,that is,“effective concentration”;a linear equation between the input load and the output response concentration of the pollution source in Daliaohe Estuary was established,and the inversion and iteration method was used to calculate the standard environmental capacity and the current environmental capacity of the sea area,and the marine environmental carrying capacity was evaluated.The calculation results show that the standard,current and remaining environmental capacity of inorganic nitrogen in the sea area are respectively-3.784 t/d,7.914 t/d and-11.698t/d,there is no remaining environmental capacity,the sea area is polluted seriously,and the carrying capacity is seriously overloaded;the standard,current and remaining environmental capacity of COD are respectively 79.438 t/d,17.349 t/d and 62.089 t/d;the standard,current and remaining environmental capacity of phosphate are respectively 0.301 t/d,0.105 t/d and0.196 t/d.They both have remaining environmental capacity,and the carrying capacity is not overloaded.Finally,the above calculation and evaluation process is compiled into a system software program.The results of this article can provide scientific basis for the marine administrative department to formulate the distribution and control plan of the total land-source pollutant discharge within the functional area or between adjacent functional areas according to the social and economic status and development trend of Yingkou area,so that the management policy is "targeted,combining large and small,precise policy".The proposal of the inversion iteration method and the compilation of the carrying capacity evaluation system also provide new methods and ideas for environmental capacity calculation and carrying capacity research in other sea areas.