Study On Heavy Metal Pollution Of Soil In The Back River Area Of Kaifeng Section Of The Lower Yellow River

The National "Thirteenth Five-Year Plan for Promoting the Rise of Central China" clearly proposes to support Zhengzhou in building a national central city,which puts Zhengzhou at a new historical height in the national strategic layout.To promote the implementation of the plan,we must base on the provincial and market conditions,adhere to the coordinated development of resources,environment and economy,effectively carry out the construction of ecological civilization in all aspects of the development of the Zhengzhou urban area,and let Zhengzhou National Central City develop with high quality within the tolerance range of resources and environment.Under this background,it is of great practical significance to make a systematic comparative study on the bearing capacity of resources and environment in Zhengzhou.This paper sorts out the research status,conceptual connotation,theoretical basis and evaluation methods of domestic and international resource and environmental carrying capacity;it conducts a comprehensive and systematic comparative analysis of Zhengzhou's resource,environment,economic and social development status.This paper follows the principles of scientific,systematic,comprehensive,dynamic,and operability,and has constructed a three-level evaluation index system of resource and environment carrying capacity,which is composed of target layer(resource and environment carrying capacity),criterion layer(resource carrying capacity,environment carrying capacity,economic and social support)and index layer(17 specific indexes such as Per capita water resources,Per capita cultivated land area,population density and Engel coefficient);Taking the data of Zhengzhou from 2010 to 2017,the data of Wuhan,Zhengzhou,Changsha,Nanchang,Hefei and Taiyuan,the capital cities of six provinces in Central China in 2017,and the data of 16 districts(cities,counties and development zones)of Zhengzhou in 2017 as samples,this paper makes a comparative study on the resource and environment carrying capacity of Zhengzhou from three dimensions of vertical,horizontal and internal by using the analytic hierarchy process.Through comparative research,this paper draws the following conclusions:Through longitudinal comparative analysis,from 2010 to 2017,the bearing capacity of the resource subsystem and the social subsystem of Zhengzhou city showed a downward trend;the bearing capacity of the environmental subsystem and the economic subsystem showed an upward trend.The overall carrying capacity of resources and the environment shows an upward trend.In 2017,it increased by 93.68% compared with 2010.Among them.This shows that the city is in a state of sustained and healthy development.Through horizontal comparative analysis,in 2017,Zhengzhou ranked sixth among the capital cities of the six provinces in the central region,with the bearing capacity of the resource subsystem;the bearing capacity of the environmental subsystem ranked second to last;the supporting capacity of the social economic subsystem ranked second,second only to Wuhan;the comprehensive bearing capacity of the resource and environment ranked sixth in the six provinces in the central region,with a certain gap with Nanchang,Changsha and Hefei.Through internal regional comparative analysis,in 2017,the carrying capacities of resource subsystems in 4 development zones is higher than 6 municipal districts and lower than 6 municipal counties(cities).The Jinshui District,Zhengdong New District and Zhongmu County in the eastern region of the environmental subsystem carrying capacity are generally high.The carrying capacity of social and economic subsystem Jinshui District,Zhengdong New District and Erqi District is higher than other areas,Xinzheng City,xinmi City and Dengfeng City are lower than other areas.The highest bearing capacity of resources and environment is in Zhengdong New Area,and the lowest is in Airport Port District.The bearing capacity of Jinshui,Shangjie,Huiji,Zhongmou,Dengfeng and Zhengdong New Area is higher than other areas.Finally,according to the comparative research results of Zhengzhou's resources and environment carrying capacity,this paper puts forward suggestions for improvement and upgrading from five aspects: establishing monitoring and early warning mechanism,improving development concept,solving the short board problem,promoting the transformation and upgrading of industrial structure and realizing the diversification of governance means in order to promote the high-quality development of Zhengzhou National Central City Construction with the improvement of resources and environment carrying capacity.