I. International standards for heavy metal content in soil
1. The Environmental Protection Agency (EPA) of the United States has formulated the soil environmental quality standard (SQGs), which includes the limit value of heavy metals. For example, for lead (Pb), the soil environmental quality standard is150mg/kg; For cadmium (Cd), the soil environmental quality standard is 0.5mg/kg.
2. EU has formulated the Guidelines for Risk Assessment of Soil Pollution (PRTR), which includes the limit of heavy metals. For example, for lead (Pb), the limit in the Guide to Soil Pollution Risk Assessment is 400 mg/kg; The limit value of cadmium (Cd) in the Guidelines for Soil Pollution Risk Assessment is 0. 1mg/kg.
3. The World Health Organization (WHO) has formulated guidelines on soil environmental quality, including the limit of heavy metal elements. For example, for lead (Pb), the limit value in the soil environmental quality guide is100 mg/kg; The limit value of cadmium (Cd) in the Guide to Soil Environmental Quality is 0.5mg/kg.
Second, China soil heavy metal content standards
1. China's national standard "Soil Environmental Quality Standard" (GB15618-2018) stipulates the limit value of heavy metal elements in soil. For example, for lead (Pb), the limit of soil environmental quality standard is 50 mg/kg; For cadmium (Cd), the standard limit of soil environmental quality is 0.5mg/kg.
2. The Ministry of Environmental Protection of China formulated the Technical Specification for Soil Environmental Quality Assessment (HJ 166-20 10), which stipulated the limit value of heavy metal elements in soil. For example, for lead (Pb), the limit of Technical Specification for Soil Environmental Quality Assessment is 50m g/kg；; The limit of cadmium (Cd) in Technical Specification for Soil Environmental Quality Assessment is 0.5mg/kg.
Third, the practical application of soil heavy metal content standards
1. Soil heavy metal content standard is mainly used to evaluate soil pollution degree and formulate pollution prevention measures. By detecting the content of heavy metal elements in soil, we can understand the soil pollution and provide basis for formulating corresponding pollution prevention measures.
2. Soil heavy metal content standards can also be used to guide agricultural production and land use. For example, for farmland with heavy metal pollution, plants with low absorption or tolerance can be planted to reduce the content of heavy metals in agricultural products and ensure food safety.
3. Soil heavy metal content standards can also be used to assess human health risks. By studying the relationship between heavy metal elements in soil and human health, it can provide basis for formulating corresponding health risk assessment and management measures.
4. Limitation of heavy metal content standard in soil
1. Due to the differences in economic development level, natural environmental conditions and types of pollution sources in different countries and regions, there may be differences in soil heavy metal content standards in different countries and regions. Therefore, it is necessary to choose the appropriate standard according to the specific situation in practical application.
2. The standard of soil heavy metal content is mainly limited to a single heavy metal element, while the actual soil pollution often involves the combined pollution of multiple heavy metal elements. Therefore, the comprehensive effects of various heavy metal elements need to be considered in practical application.
3. Soil heavy metal content standards mainly focus on the impact of long-term exposure on human health, while the risk assessment of short-term exposure and acute poisoning is relatively small. Therefore, it is necessary to comprehensively consider the risks of long-term and short-term exposure in practical application.
To sum up, experts should be organized to review and demonstrate the formulation of soil pollution risk control standards, and the opinions of relevant departments, industry associations, enterprises and institutions and the public should be solicited. The implementation of soil pollution risk control standards should be evaluated regularly, and the standards should be revised in time according to the evaluation results. The competent department of ecological environment of the people's government at or above the provincial level shall publish the soil pollution risk control standards on its website;
Legal basis:
Law of People's Republic of China (PRC) on Prevention and Control of Soil Pollution
Article 6
People's governments at all levels shall strengthen their leadership in the prevention and control of soil pollution, and organize, coordinate and urge relevant departments to perform their duties of supervision and management of soil pollution prevention and control according to law.
Article 7
The competent department of ecological environment in the State Council shall implement unified supervision and management on the prevention and control of soil pollution throughout the country; The competent departments of agriculture, rural areas, natural resources, housing and urban construction, forestry and grassland in the State Council shall supervise and manage the prevention and control of soil pollution within their respective responsibilities. The competent department of ecological environment of the local people's government shall exercise unified supervision and management over the prevention and control of soil pollution within their respective administrative areas; The competent departments of agriculture, rural areas, natural resources, urban and rural housing construction, forestry, grasslands and other local people's governments shall supervise and manage the prevention and control of soil pollution within their respective functions and duties.