Accumulation And Migration Characteristics Of Cadmium And Lead Elements In Soil Crops Around A Metal Smelting Plant In Western Inner Mongolia

China is a major agricultural country,and heavy metal pollution in farmland is one of the important factors affecting food security production.By studying the migration and accumulation characteristics of heavy metals in crops in polluted areas,it is possible to clarify the impact of heavy metals on corn and effectively prevent and control them in production activities.In this study,the corn field around a metal smelter in western Inner Mongolia was selected as the research object.After conducting a thorough investigation of the area,considering the significant impact of wind direction and distance factors,a fan-shaped sampling point was set from the metal smelter as the starting point,from northeast to southwest.A total of 40 soil sample collection points and 40 corn sample collection points（excluding wasteland）were set up.By measuring the contents of cadmium（Cd）and lead（Pb）in different organs of soil and corn,analyzing their cumulative distribution characteristics in different directions and distances,and evaluating the migration ability of heavy metal elements in plants.To provide theoretical basis for solving the problem of soil heavy metal pollution and crop heavy metal exceeding standards in the research area.The research conclusion is as follows:（1）The average content of cadmium element in the soil of the study area is 0.49mg·kg^-1,and the point exceeding rate can reach 92.5%.The high value area is mainly distributed in the southeast of the smelting plant,with a decreasing trend with increasing distance.The average content of lead element is 27.94 mg·kg^-1,and the point exceeding rate reaches 85%.The high value area is evenly distributed in the southwest,due south,and southeast directions of the smelting plant,but there is no significant difference in different directions and distances（P>0.05）,Overall,the soil in the study area is heavily contaminated with cadmium and lead elements.（2）The average content of available cadmium in the soil of the research area is 0.21mg·kg^-1,and the high value area is mainly distributed in the northeast direction of the smelting plant,with a decreasing trend with distance.The average content of available lead in the soil is 1.39 mg·kg^-1,and the high value area is mainly distributed in the south of the smelting plant.However,the highest available lead content is found in the area 3-4km away from the smelting plant,but there is no significant difference in content between different distances（P>0.05）.（3）The plants in the study area exhibit a certain degree of cadmium and lead enrichment.The vertical distribution of cadmium in maize is characterized by root>stem>leaf>fruit,while the vertical distribution of lead in maize is root>leaf>stem>fruit.The average contents of cadmium and lead in the roots are 0.55mg·kg^-1and 2.34 mg·kg^-1,respectively.The high value areas of cadmium are mainly distributed in the south of the smelting plant,while the high value areas of lead are mainly in the southwest direction;The average contents of cadmium and lead in the stem are 0.47 mg·kg^-1and 0.31 mg·kg^-1,respectively.The high value areas of cadmium are mainly concentrated around the smelting plant,while the high value areas of lead are scattered in all directions of the smelting plant;The average content of cadmium and lead elements in the leaves is 0.38 mg·kg^-1and 1.21 mg·kg^-1.The high value areas of cadmium are mainly distributed in the south of the smelting plant,while the high value areas of lead are distributed in a sheet-like manner in the research area;The average contents of cadmium and lead in fruits are 0.22 mg·kg^-1and 0.12 mg·kg^-1,respectively.The distribution of cadmium content is relatively uniform,while the high value areas of lead are concentrated in the areas close to the south.（4）The transport capacity of cadmium in various organs of corn is stem>leaf>fruit,and the transport capacity of lead is leaf>stem>fruit.The enrichment ability of various organs in maize for cadmium is stem>root>leaf>fruit,and the enrichment ability for lead is root>leaf>stem>fruit.（5）From the overall analysis of soil cadmium and lead content in the study area,as well as the cadmium and lead content in various organs of corn,it can be concluded that the absorption and accumulation of heavy metals by plants is not significantly related to the total amount of heavy metals in the soil,but is directly related to the available content of heavy metals.Therefore,it is necessary to effectively manage and control the soil in the research area to ensure the safe consumption of food crops.