The Influence Factors And Spatial Distribution Of PAHs In The Topsoil Of Typical Coking Base

Polycyclic aromatic hydrocarbons(PAHs)are the products of incomplete combustion of fossil fuels such as coal,petroleum and so on,it is a class of organic pollutions with carcinogenic,teratogenic and mutagenic.At present,the coking enterprise in the study area in the production process emissions of PAHs have caused its surrounding agricultural soil contamination,which could affect the safety of crops and agricultural products,thus threatening the health of local residents.In this paper,the study of factors affecting the content of PAHs,spatial distribution and pollution condition,which in order to provide scientific basis for scientific management of government departments on the coking enterprises and coking pollution soil scientific prevention and treatment.In this study,the PAHs content in the surface soil of the surrounding farmland of a large base of coking as the research object,through the visual interpretation of the high resolution remote sensing image obtained the coke oven position,based on the meteorological data of 1981-2008 to determine the prevailing wind and modify it,using the R2012b MATLAB programming to calculate the integrated projection distance between the source and the sampling points on the prevailing wind direction,based on the measured PAHs content data in the surface soil in the study area,using classical statistical methods and simple kriging methods in ArcGIS Geostatistical module to explore the factors of PAHs in the soil,the pollution status and spatial distribution pattern.The main conclusions of this study are as follows:(1)From the true color of the high resolution remote sensing image visible,coking plant in a large scale range of large black area,a specific location in the plant is located in a column shaped chimney,and there was a white cloud of smoke above the chimney;in the vicinity of the chimney with two columns of about a few hundred meters long,each showing similar to the comb texture,and they are generally arranged in parallel.According to the graph structure and image features,15 coking pollution sources were identified in the study area.(2)By using the idea of matrix operation and programming in MATLAB,a mathematical calculation method is established to calculate the distance between multiple points,the projection distance in any direction and the azimuth between two points,and calculated the integrated projection distance on the prevailing wind in the study area between 15 to 36 coking pollution sampling points.(3)The prevailing wind direction in the study area is southwest wind,the revised azimuth Angle is 229.7899 °.Correlation analysis showed that 36 sampling points of PAHs and their respective 15 coking pollution sources sum projection distance in the prevailing wind direction was significantly correlated,it can be known that the prevailing wind direction and its projected distance are closely related to the content of PAHs in soil samples.(4)In the downwind direction of the prevailing wind direction of the pollution source,study area in the topsoil of 16 SU EPA priority control the total PAHs content,showing:the closer the distance to the pollution source is,the higher the content is;on the space,the overall characteristics of southwest high,northeast low;northwest and southeast of the study area is relatively light pollution.The spatial distribution pattern is mainly caused by the spatial distribution of the pollution source and the prevailing wind direction.(5)According to Maliszewska-Kordybach pollution grade evaluation standard,in the agricultural soil of the study area,the proportion of PAHs content light,medium and heavy pollution sample points roughly accounted for 41.7%,41.7%AND 16.7%of the total sample points.It can be known,soil pollution in the study area has been very serious,urgent need to strengthen the management of the relevant departments and scientific control.