Heavy Metal Pollution and Ecological Risk Assessment of Cultivated Land Soil in the Farming Areas of Coastal China:A Case Study of Donghai County,Jiangsu Province

摘要

Classical statistics,Inverse Distance Weighted and Hakasnson potential ecological index were used to study the distribution characteristics of 8 kinds of heavy metals(Cr,Ni,Cu,Zn,As,Cd,Pb and Hg)as well as their potential ecological risks in the topsoil(0-20 cm)of cultivated land in Donghai County,a typical agricultural area along the Southeast Coast of China.The results showed that the average content of heavy metals in the cultivated soil of Donghai County was not over the risk screening values set in the Environmental Quality Standard for Soils.However,it was worth noting that in some of the sampling points,the content of Cr exceeded the risk screening value,and the standard exceeding points accounted for 24.74%of the total.In addition,the average content of Cr,Ni,As,Cd,Pb and Hg exceeded the soil background values of Jiangsu Province,and values for Cd,Cr and Pb were more than 1.5 times of the soil background value of Jiangsu Province.The heavy metals were at the medium integrated potential ecological risk level,and the potential ecological risk indices were high in the east and low in the west,and distributed in interlaced island shape.The potential ecological risk indices of the plains in the east were higher than those of the central gentle slope area and the western hillock area.The potential ecological risk was at a high level in Niushan Town which was situated the county center and in some regions with high urbanization levels.