Study on Risk Model of Heavy Metals and Risk Element Pollution in Surface Farmland Soil in Cold Black Soil Region of China – Qianjin Town As an Example

In order to study the pollution, ecological risk and health risk of heavy metals and risk elements in the surface farmland of the cold black soil area in Northeast China, the main grain production area in China, based on the collection and analysis of samples in 2010 and 2021, the soil heavy metals and risk element in this area were assessed by using the method of Geo accumulation index (Igeo), potential ecological hazard index (RI) and health risk assessment (HRA) model. The results show that there are heavy metals and risk element pollution in the soil, which is accumulated year by year. The average contents of Hg, Cd, Cr, Ni, Pb, Zn, As and Cu in the soil in this area are higher than the background values of Qianjin town. The heavy metals and risk element in the black soil and farmland in the cold area are obviously affected by human activities. There are different degrees of regional variability, and the coefficient of variation of Hg is 79%; Some elements have ecological risk, and Hg and Cd are the main influencing elements of soil ecological risk in shallow farmland; Heavy metals and risk element have non-carcinogenic health risks to children. The carcinogenic risk index of adults and children exceeded the soil treatment benchmark value of 10-6 proposed by EPA, As is the element that contributes the most to non-carcinogenic health risk and carcinogenic health risk in adults and children. In view of the continuous accumulation of heavy metals and risk element in farmland soil, it is necessary to improve ideological understanding, improve laws and regulations, formulate norms and standards, develop methods and technologies, and scientifically prevent and control heavy metals and risk element pollution.