Pollution, risks, and sources of heavy metals in sediments from the urban rivers flowing into Haizhou Bay, China

Haizhou Bay is an open bay located in northern Jiangsu Province, China. This study analyzes the changes in the coastline, coastal development, and water quality of Haizhou Bay between 2006 and 2016. The box model method and numerical simulation are adopted to calculate the environmental capacities of Haizhou Bay in 2006 and 2016, analyze changes to environmental capacity features, and assess the influencing factors over this period. The scenario analysis method is used to discuss the influencing mechanism and degree of influence of factors (e.g., the water quality difference inside and outside the bay, and sea reclamation) on the environmental capacity and calculate the contribution of each influencing factor. The changes in terrain triggered by sea reclamation and water quality from 2006 to 2016 reduced the total environmental capacity of Haizhou Bay, with an influencing ratio of 0.198:0.802. In other words, poorer water quality inside the bay reduces the environmental capacity by a degree of 4.05 times that of sea reclamation. This study can offer guidance on related future research aiming to protect the marine environment of Haizhou Bay and control the total amount of pollutants discharged into the sea.

https://www.mdpi.com/2073-4441/12/11/2990/pdf

Characteristics and Mechanism of the Environmental Capacity Changes in Haizhou Bay, Northern Jiangsu, China from 2006 to 2016

Variations in the marine seawater environment and the dominant factors in the Lianyungang coastal area

To solve increasingly serious water pollution problems, it is necessary to systematically manage water resources, water environment, and water ecology as elements of a watershed. Comprehensive watershed water pollution control should regard the basin as a whole, respect the natural laws of the river and lake system, and focus on the protection and restoration of its natural ecological environment so that the comprehensive ecological service functions of rivers and lakes can be fully realized. Based on the concepts of environmental capacity (EC) and environmental flow (EF), this study established watershed water pollution control scheme prediction and evaluation methods to explore the changes in the water environment and water ecology in the basin under different water pollution control schemes. The MIKE11 model was used to construct a hydrologic and water quality model of the study area, the one-dimensional water quality model was used to calculate the water environmental capacity, and the Tennant method was used to evaluate the environmental flow. In this study, the method was applied to the Luanhe River Basin of Chengde, Hebei Province, China. It simulated the concentration changes of four pollutants—namely, NH3-N, COD, TN, and TP—under eight different water pollution control schemes, and the responses of EC and EF were compared and analyzed. Some conclusions are as follows: (1) Reducing point source pollution has the most obvious effect on water pollution prevention, especially on NH3-N and COD, while reducing nonpoint source pollution is weaker and the effect of increasing upstream water is the weakest. (2) The increase in up-stream water inflow and reducing point source pollution can greatly increase the EC of NH3-N and COD. The EC of TN can be greatly increased by reducing point source pollution, and the EC of TP can be greatly increased by reducing nonpoint source pollution. (3) The increase in upstream water inflow can improve the EF level to a certain extent. This method can also be applied to other similar river basins, providing valuable suggestions for rationally formulating water environmental management strategies and for promoting the sustainable development of the ecological environment and social economy in the river basin. 

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A Developed Method of Water Pollution Control Based on Environmental Capacity and Environmental Flow in Luanhe River Basin

According to the layout of Changxingdao Island,the three programs of the discharged points of pollutants were madeOn this basis,and based on the principle of the marine environmental capacity,the permissible discharged amount of COD,inorganic nitrogen and active phosphate were calculatedThe results of calculation will provide the scientific basis for the optimize scheme of discharged sewage into sea and total mass control program in the industrial areas of Changxingdao Island

Total amount control of pollutant discharged into sea area around Changxingdao Island

To calculate the environmental capacity of the estuaries of Haizhou Bay in northern Jiangsu, China in 2006 and 2016, this study employed the share ratio approach and established a tidal hydrodynamic model and a water quality diffusion model by the Delft 3D software to perform the numerical simulation. The article compared the environmental capacity in 2006 and 2016, and analyzed the changes between these years. The scenario analysis method was used to explore the influence of factors on the environmental capacity and quantify the contribution of each influencing factor. The results show that the theoretical environmental capacity was reduced by 32.718 tons/day (28.56%) from 114.571 tons/day in 2006 to 81.853 tons/day in 2016. The remaining environmental capacity was reduced by 6.955 tons/day (56.92%) from 12.219 tons/day in 2006 to 5.264 tons/day in 2016. The changes in topography and the amount of runoff into the ocean through the estuaries of Haizhou Bay between 2006 and 2016 reduced the total environmental capacity of the estuaries by an influence ratio of 0.363:0.637. The study will provide the management of the marine environment of Haizhou Bay with information to control the aggregate pollutants flowing into the ocean and support the social and economic sustainable development of Haizhou Bay.

The Characteristics and Mechanism of Changes in the Marine Environmental Capacity of the Estuaries of Haizhou Bay in Northern Jiangsu from 2006 to 2016

Jing Wang

Papers

The Characteristics and Mechanism of Changes in the Marine Environmental Capacity of the Estuaries of Haizhou Bay in Northern Jiangsu from 2006 to 2016

Characteristics and Mechanism of the Environmental Capacity Changes in Haizhou Bay, Northern Jiangsu, China from 2006 to 2016