Soil Characteristics And Potential Ecological Risk Assessment Of Heavy Metals In Tidal Flat Of Southeast Coast Of Liaodong Peninsula

Soil is an organic part of beach wetland environment.Its characteristics and pollution state can reflect the health status of tidal flat wetland ecosystem.Based on this,the research methods of field investigation and sampling,soil partial physicochemical properties,X ray fluorescence spectrum data analysis and soil potential ecological risk a ssessment are used to study the soil environmental characteristics,ecological risk and spatial difference of heavy metal pollution in the coastal area of southeastern Liaodong Peninsula(include Donggang and Zhuanghe,Dayang estuary and Zhuanghe estuary,Inside and outside of the Yalu River Wetland Reserve)are analyzed.The main conclusions are as follows:(1)The soil clay content of Donggang coastal beach is 43.71%~56.83%,with an average value of 50.27%;The particle content is between 16.39%~29.51%,the average value is 22.66%;the sand content is between 26.23%~27.32%,with an average value of 27.06%,it can be seen that the soil texture type of Donggang coastal beach is clay.(2)The pH value of coastal beach soil in Donggang is 6.82~7.75,with an average value of 7.37,the overall presence of weak alkalinity;the content of soil organic matter is 1.7%~9.1%,the average value is 4.8%,the coefficient of variation is 45.8%,and the spatial difference is small.The content of K and Fe elements in soil is the largest,the average values are 75.2g/kg and 93.7g/kg,and the contents of C,Ca,Mg and Cl are the next,the content are between 59.3g/kg~124g/kg,and the contents of P,N,S and species are the lowest,and the content of the elements is the lowest.(3)From the whole point of view,the average content of heavy metal Ni elements in the beach soil of the southeast coast of Liaodong peninsula is more than the star ting value of moderate pollution,and the average content of Cr elements exceeds the initial value of pollution accumulation.The order of the average content of the 6 heavy metal elements is Cr > Zn > Ni > Pb > Cu > As.From the point of view of regio nal differences,the average content of Cr,Cu and As in the coastal wetland soil of Z huanghe is higher than that of Donggang,and the average content of Zn,Ni and Pb is lower than that of Donggang,and the average content of Ni elements in the ocean estuary is higher than that of the Zhuanghe estuary,and the average content of Cr,Zn,As,Pb and Cu elements are lower than that of the Zhuanghe estuary.The contents of Cr,Cu and As in the protected area are lower than those outside the protected are a,and the contents of Ni,Zn and Pb are higher than those outside the protected area.(4)The average value of single factor pollution index of Cr,Ni,Cu,Zn,Pb andAs elements in the beach soil of the southeast coast of Liaodong peninsula were 0.96,1.94,0.91,0.80,0.69 and 0.84,respectively,reflecting the moderate pollution area of Ni and the mild pollution area of Cr and Cu in the study area.Among them,Zhuang he coastal beach wetland soil is Cr,Ni light pollution area,and near Cu light pollution area,and Donggang city belongs to Ni pollution area;oceanic estuary is Ni medium polluted area,Zhuanghe estuary is Cr,Ni,Cu,As light pollution area;the nature reserve is Ni medium polluted area,and it is also close to Cu,Zn light polluted area,the Ni and Cr light pollution areas outside the protection area are also close to the Cu light pollution area.(5)The average pfi rE value of 6 heavy metals in the study area is less than 40,and the comprehensive risk index is 35.12,the results showed that all 6 heavy metals in the coastal wetland soil of Liaodong peninsula had slight potential ecological risk,and the threat of integrated potential ecological risk is also mild.Among them,the comprehensive potential ecological risk threats of 6 heavy metals in the coastal tidal flats such as Zhuanghe,Donggang and the Dayang estuary all show a slight degree of threat.