Spatial Distribution, Sources And Risk Assessment Of Soil Heavy Metals In Typical Industrial Park In Shanxi Province

With the advancement of industrialization,urbanization and agricult-uralization,more and more heavy metals are discharged into the soil ecosystem,leading to the destruction of the basic functions of soil,causing ecological degradation and human health risks.In particular,the accumulation of heavy metals in soil in various industrial parks in some industrial cities has caused widespread concern among academia,government and the public.The types of industries involved in the chemical economy recycling industrial parks in small and medium-sized cities in Shanxi Province include coal chemical,ceramics,mechanical equipment,energy transportation,new materials and carbon,and the industrial parks have a long production time of coal coking process,which may have a high potential pollution hazard.In this thesis,a chemical recycling economy industrial park in Shanxi Province is taken as the research area,and the heavy metal elements Cr,Ni,Cu,Zn,Cd,Pb,Hg and As in the soil of the industrial park are used as the research objects to explore the accumulation of each heavy metal content,spatial distribution,sources and ecological risks in the soil of the park.The main research results are as follows:（1）The elemental contents of heavy metals Cr,Ni,Cu,Zn,Cd,Pb,Hg and As in the surface soil of the industrial park were 68.9,31.21,20.96,80.01,0.17,20.27,0.07 and 11.04 mg·kg^-1,respectively,and the average content of each heavy metal element except Cu exceeded the background value of Shanxi Province;among them,the Hg and The variation coefficients of Hg and Cd elements were greater than 50%,indicating anthropogenic disturbance.In addition,the content of Hg elements in the surface soil outside the industrial park is not much different from that in the park,while the content of the remaining seven heavy metal elements is lower than that in the park.（2）The spatial distribution of the content of the eight heavy metal elements in the surface soil of the industrial park differs significantly,and all of them have high value areas in the southwest of the park;the content of most heavy metal elements in the profile soil shows the characteristics of high in the upper layer and low in the lower layer at the depth of 0～40 cm,and there is no obvious pattern in the distribution changes of the rest of the soil layers,and the vertical distribution of heavy metal elements in the profile soil of different industrial types The vertical distribution of soil heavy metal elements in the profiles of different industrial types has a strong fluctuation.（3）The main sources of Ni,Cr and As in the surface soil of the industrial park are natural sources（soil-forming parent material）;the emissions of coal combustion and"three wastes"are an important source of Cu,Zn and Hg in the soil;the sources of Pb and Cd are mainly influenced by automobile exhaust and agricultural fertilization.In addition,the p H of the surface soil has the greatest influence on the heavy metal elements.（4）The single factor index results show that the Cr,Cu,Zn,Cd and Pb elements in the surface soil are at a slight pollution impact level,but the single factor index of Hg elements is greater than 2,and the pollution level is relatively high.The Nemero index shows that the overall level of heavy metal pollution in the park is at a moderate pollution level.The ground accumulation index points out that the Hg element is in a light pollution state.The results of potential ecological risk assessment show that the single potential ecological hazard index of Hg and Cd elements is greater than 160,which has a strong potential ecological risk level,and the average value of the single potential ecological hazard index of the remaining heavy metal elements Cr,Ni,Cu,Zn,Pb and As is less than 40,which is a slight ecological risk degree,indicating that Hg and Cd are the key ecological risk factors of the industrial park.The comprehensive ecological risk results of the surface soil heavy metal elements show that the park belongs to the medium ecological risk level.Through the spatial distribution of the assessment results of each index,the industrial park is distributed with higher grade ecological risk areas,and mainly concentrated in the southwest,central and northeast of the park.