Research On Regional Soil Environmental Capacity Based On Risk Constraint

Soil safety is the foundation for the sustainable development of human society and a key element in maintaining ecological balance.Soil environmental capacity and risk warning are the core contents of soil safety research.However,with the rapid progress of population growth,urbanization,and industrialization,global soil pollution has become increasingly severe.Among them,heavy metal pollution in the soil is particularly prominent and poses a serious threat to human health and the ecological environment.Therefore,this research enhances the conventional dynamic model for assessing soil environmental capacity in cases of prevalent heavy metal pollution.It achieves this by determining the proportional impact of various heavy metals on both human health risks and potential ecological risks,taking into account different types of land usage.This aims to achieve dynamic,quantitative,and visualized pollution and risk prediction and warning.Improving the "status assessment-pollution source identification-risk assessment-risk warning" system for soil heavy metals in order to provide technical support for safe soil utilization and risk prevention and control.This study takes the basin copper smelting area as the research area,evaluates the current status of soil heavy metal pollution in the research area through field investigation and sampling data of soil heavy metals,and conducts source analysis and risk identification using statistical,spatial,and source analysis techniques.Based on this,The improved dynamic soil environmental capacity model is used to warn of soil pollution and risk in the next 20-50 years.The key findings are as follows:(1)This study explores the content and sources of seven heavy metals in the topsoil of the research area.The soil environmental quality in the study area is relatively good.However,there is still severe heavy metal pollution in some local areas.Except for As and Cr elements,the content of other heavy metals exceeds the background value of the soil environment in the research area.Among them,Cd pollution is the most serious,with a mean value of pollution index of up to 2.7.Through receptor modeling,the main sources of heavy metal pollution in the topsoil of the research area are identified,including natural sources,industrial sources,and mixed sources dominated by agriculture.(2)An evaluation was executed to determine the potential ecological and health hazards posed by seven distinct types of soil heavy metal pollution in the study area.Findings revealed that the average comprehensive ecological risk index for soil heavy metals in the study area was 116.20,indicating a low to moderate level of ecological harm.Among these pollutants,Cu(copper)and Cd(cadmium)emerged as primary contributors to environmental damage.As for health risks,exposure to heavy metals in soil did not lead to significant levels of carcinogenic or non-carcinogenic risks among both adults and children.Nevertheless,consumption of rice contaminated by heavy metals through dietary exposure resulted in cumulative carcinogenic risk and cumulative non-carcinogenic risk exceeded safety thresholds.(3)In the study area,atmospheric deposition was identified as the primary source of heavy metals present in the soil.With regards to agricultural soil,all six current heavy metals,aside from Cr,exhibit negative environmental carrying capacities,whereas only Cr and Zn in construction soil have negative carrying capacities.There may be a decline in the capacity for heavy metals in agricultural land,with the exception of Cu,over the next two decades,increasing the risk of pollution,according to an assessment of the future risk and capacity of seven types of heavy metals in agricultural and construction soils in 2042 and 2072.A concern is also posed by the pollution risk associated with five additional heavy metals in built-up areas.