Research Progress in Soil Remediation of Lead,Cadmium and Arsenic Pollution
With the rapid development of industry,agriculture,mining and urbanization,a large number of heavy metals and other pollutants enter the soil environmental system,and the combined pollution of heavy metals in soil caused by this problem has attracted much attention.According to the 2014 National Soil Pollution Status Report,19.4％of China's arable land has exceeded the standard for heavy metal pollutants such as Pb,Cd and As,with the sites exceeding the standard for these three typical heavy metals ranking at the top,resulting in a polluted area of over 50 million acres.Soil heavy metal pollution is characterized by long-term persistence,durability,and difficulty in degradation.Through surface and subsurface runoff,it can be transferred from the soil to surrounding water bodies,exacerbating water heavy metal pollution.At the same time,heavy metals in land and water can be absorbed by crops,entering the food chain and accumulating in organisms,causing significant harm to human health.Pb has irreversible effects on the nervous system and children's intellectual development.Cd is a highly toxic heavy metal,long-term exposure to cadmium-contaminated environments may lead to diseases such as kidney damage,osteoporosis,and cancer.As is associated with health issues including cancer,skin diseases,and cardiovascular diseases.However,the coexistence of heavy metals such as Pb,Cd and As in soil in composite pollution poses greater environmental hazards compared to single pollution.Therefore,it is of great significance to comprehensively understand the current situation,characteristics,and remediation technologies of heavy metal composite pollution for the prevention and control of heavy metal pollution and the safe utilization of soil.This review provides a comprehensive overview of the current status,sources of pollution,and distribution and migration characteristics of Pb,Cd and As in soils affected by composite pollution.It particularly emphasized the impact of soil pH,redox potential(Eh),soil organic matter(SOM)and soil types on the migration and transformation of Pb,Cd and As.The study presented a summary of the research progress in the remediation of Pb,Cd and As composite pollution using physical remediation methods,solidification/stabilization techniques,and bioremediation approaches.It discussed the advantages,disadvantages,and applicability of various soil remediation technologies and provides an outlook on future development directions.Specifically,the ex-situ soil washing method had a fast remediation rate but was expensive,easily disrupts soil structure,and might cause secondary pollution.The electrokinetic remediation method had simple equipment operation but was relatively costly,consumed a significant amount of energy,and might pose safety hazards.The bioremediation method could improve soil quality and maintain ecological balance but had a slow remediation process and is highly influenced by the environment.The solidification/stabilization techniques had become the mainstream technology for the remediation of composite pollution in soils due to their high efficiency,low cost,and easy implementation.Furthermore,due to the pressing demand for the large-scale disposal of metal mine wastes in China,the research on developing new solidification/stabilization materials utilizing local mining solid wastes for the remediation of Pb,Cd and As composite polluted soils would become a key focus in the field of solidification/stabilization technologies.
NETL
NSTL
万方数据
