Surface Soil Element Distribution And Soil Pollution Based On Complex Network

Urban soil is the homeland on which humans depend,affecting the city’s ecological functions,environmental conditions,and social and economic operations.This ultimately determines the quality of the city’s ecological environment and human health.With the rapid development of industrialization and urbanization,soil pollution caused by metals and metalloids is a serious environmental problem especially heavy metal pollution in the surface soil.Therefore,it is necessary to analyze the spatial distribution of soil pollution.Moreover,it is critical to identify soil regions with the same or similar pollution problems for collaborative governance of trans-regional soil pollution and sustainable development.We use China’s Baotou as an example.The statistical analysis and spatial autocorrelation analysis of the elements and oxides in the surface soil of Baotou area were carried out to preliminarily analyze the spatial distribution agglomeration characteristics of elements and oxide content in the surface soil of Baotou area.Based on the data of 2820 sampling points in main urban areas and some suburban areas of Baotou,we constructed a relationship network model for sampling points in surface soil by using the complex network method.We combined the network method with spatial geographic information to analyze the spatial agglomeration characteristics of the surface soil pollution in Baotou China.The results are as follows:（1）The spatial distribution of most elements in the surface soil of Baotou has significant positive spatial autocorrelation,and the spatial autocorrelation of Ni element is the strongest.（2）Sampling points distributed in the Baotou area with serious and similar pollution problems are mainly in Baotou Steel tailings dam,power plant ash pond,Kundulun River and Donghe District of Baotou City and its southeast suburban area.Sampling points concentrated in the tailings dam,such as 506D,509C,538B,538D,541A,541C and other sampling points have the most serious pollution problems.328D and 544A are scattered,but they have a close co-anomaly relationship with the tailings dam.We suggest that these areas should be unified to give priority to pollution control.（3）There is an obvious difference for Al₂O₃,B,Hg and U,which are abnormal in the power plant ash storage pools,but normal at the tailings dam.Consequently,pollution control for power plant ash storage pools needs to be different from pollution control at the tailings dam.（4）579D,580A,580B,643B and other sampling points upstream of the Kundulun River have a close co-anomaly relationship with the tailings dam.It is necessary to strengthen the purification treatment of sewage upstream of the Kundulun River to reduce the spread of pollutants.These results provide a theoretical basis for the government to formulate specific cross-regional collaborative governance measures.