1。 The pollution problems and causes of contaminated soil in prominent areas are analyzed as follows:
According to an incomplete survey, the polluted farmland in China covers an area of about1500,000 hectares with 3,250 mu of cultivated land, which is polluted by irrigation and sewage. Solid waste storage accounts for 2 million mu of land and damages, accounting for more than one tenth of the total area. Cultivated land, the country's12 million tons, the direct economic loss caused by heavy metal contaminated food every year exceeds 200 million yuan. There are, even in some areas, heavily polluted areas and high-risk areas with serious soil pollution.
The density of one or more elements polluted by heavy metals is 4.0 5.0 45, about 60 kinds. As and Se are nonmetallic, but their toxicity and some characteristics are similar to those of heavy metals and heavy metal pollutants in inclusions, such as Se and Se. Heavy metal pollution of soil environment mainly refers to biotoxic mercury, cadmium, lead, chromium and metals, including copper, cobalt, nickel, tin, and V and other pollutants. Most people are concerned about lead, mercury, cadmium, lead, chromium and arsenic, which are called "Big Five" (research progress of heavy metal pollution in farmland soil). An insider's exposure to heavy metals in the soil is multi-channel. First of all, in the process of forming substances containing heavy metals with different substrates, the parent materials of soil are very different. In addition, human industrial and agricultural production activities, but also caused heavy metal pollution of air, water and soil (soil heavy metal pollution status and control methods). In China, land contaminated by cadmium in 25 counties involving 1 1 provinces and cities. The cultivated land with 44% cadmium contaminated rice area in Jiangxi Province has formed Shenyang in 670hm2, and the cadmium content in the soil irrigated by sewage in a county town is as high as 130mg/kg, and in Chengdu, the rice irrigated by cadmium-containing wastewater reaches 1? 65mg/kg。 The monitoring results of National Environmental Monitoring Center, Ministry of Agriculture 1996 to 1998 show that cadmium pollution from sewage irrigation accounts for 9% of the area? The largest heavy metal exceeds the standard of 56? The over-standard rate of agricultural cadmium reaches 10? 2% (reclamation project with Hefei, 200 1). What is the sewage irrigation area of farmland soil polluted by cadmium in different degrees in major cities of China, including suburbs, Xi 'an and Shenyang? Soil cadmium pollution is particularly serious, for example, the cadmium content in farmland soil in Shenyang city is 0? The content of 88 mg/kg sewage irrigation area in Xi 'an is 0? Phytoremediation Mechanism of Cadmium Contaminated Soil (628mg/kg)
The content of soil pollutants magnesium and magnesium in cricket rock county is 43%, the pollution characteristics are serious, the sampling points above the pollution level are 2 1. 16 times. There are only 2 1 1 and 238 sampling points, in order to reach the standard of cleanliness, pollution-free B seems to be a more extensive and serious pollution level of more than 50% of the samples, and the concentration of the sampling point soil is due to Shitang in Xiuyan County and the wind source area in Pianling. There are many bad soils in Liaoyan County, bearing in mind that in the process of getting their hands on brooms, small state-owned and small towns and villages, because mining and smelting enterprises, light-burned magnesium and heavy-burned magnesium magnesite processing industries release a large number of pollutants such as MgO and SO2. Is it a white powder that forms the landing surface of MgCX/vlgO? The combination of magnesium (H0)2 and other reaction products and large particles is dispersed in the soil. In the soil, magnesium sulfate and magnesium chloride are widely present+in this area, a crust covering combined with the surface is formed, which fundamentally blocks the growth of crops. Although crops grow in some areas, it is a greater threat to people's health and other biosoluble Mg that crops absorb from the soil. Point source pollution of B mine (soil pollution and its control strategy in eastern mountainous areas of Liaoning Province). adsorb
The cadmium pollution of rice is obviously stronger than that of corn, soybean and other crops. Due to various human factors, including mining and industry, agriculture and traffic sources, such as varieties of heavy metals, heavy metals pollute the soil (current situation and control methods of heavy metal pollution in soil).
2。 ? A large area of farmland is irrigated by sewage contaminated by soil.
Sewage irrigation and other wastes. In Zhangshi irrigation area of Shenyang, the pollution of irrigation sewage of more than 25 million hectares of cultivated land for more than 20 years, with a weight of Mick kg, has led to serious cadmium pollution. 2 130000 hectares in Tianjin suburbs are polluted by sewage irrigation farmland. Farmland in the suburbs of Guangzhou is polluted, with sewage irrigation of 2 700hm 2 2, and 46% of the suburban cultivated land is produced in the polluted areas where1333 hm ~ 2 soil is contaminated with pollutants. In the mid-1980s, the sampling survey of sewage irrigation area in Beijing showed that there were 36% brown rice pollution problems in about 60% soil (the present situation of soil pollution in China and its countermeasures).
As early as 1930s, Fushun refinery wastewater was discharged into Hunhe well to irrigate rice. In 1950s, with the development of agricultural production in arid and semi-arid areas in the north, due to the shortage of water resources, in order to make full use of sewage as fertilizer, the popularization of sewage irrigation area played a positive role in promoting local agricultural food production. 1983, the sewage irrigation area is 2×1060,000 hm2. However, due to the long-term sewage pollution of soil-crop irrigation system has been exposed, in order to solve the soil environment, the application and development of sewage land treatment system.
Investigation of soil pollution in typical areas of Yangtze River Delta, Pearl River Delta and central and southern Liaoning urban agglomerations, pilot project of comprehensive management to repair contaminated soil and standard system of soil environmental quality in typical areas, establishment of perfect risk assessment, completion of draft soil pollution prevention and control law ",effectively preventing new businesses and new pollutants from failing in terms of types and types of pollutants, new technologies, new products and new application procedures, which will affect more persistent and dangerous pollutants and pollutant content. With the development of economy, For example, the data show that in recent years, in Shanghai, the content of mercury and cadmium in soil increased to 50％ (POPs), but in some areas, it was excessive in southern Zhejiang, and the detection rate of heavy metals such as copper and zinc in soil of persistent organic pollutants reached100%.
Reportedly, the Liaohe River and the Liaohe River Basin are the traditional industrial and mining fields in China. A convenient transportation and rich mineral resources, coal, petroleum, steel, mining, industrial economic structure, long-term inefficient resource utilization, pollution, high intensity, low pollution sources, pollution control level, serious pollution in chemical, metallurgical, mining and pharmaceutical industries, outdated equipment and some enterprises, backwardness, insufficient pollution prevention facilities, and weak environmental monitoring, early warning, emergency response and environmental law enforcement capabilities in the Liaohe River Basin, environmental law
People also pointed out that the pollution of soil and water affects each other alternately. On the one hand, some sewage irrigation causes soil shortage and pollution, and water resources in Liaohe River will take a long time to solve this problem. Sewage irrigation with industrial and agricultural water makes a large number of toxic and harmful substances enter the soil and accumulate to a certain extent, exceeding the self-purification of soil. The limitation of Liaohe River Basin, such as Anshan and Liaoyang, is caused by the exploitation of mineral resources, and the development of perennial soil pollution is very serious.
Experts pointed out that the relatively high level of resources and heavy industry and industrial production based on the economic structure, the difficulty of pollution and pollution control, driven by economic interests, some enterprises do not install and operate pollution control facilities in place, and the phenomenon of sewage residue discharged at will occurs from time to time, which makes people hard to prevent; At the same time, the local government has turned a blind eye to the phenomenon of light pollution.
The problem of pollution control in Liaohe River is a more important test-the continuous impact of the current economic crisis is an urgent need to revitalize the old industrial base in the northeast of China. On the one hand, the rule of serious pressure on soil and water pollution in Liaohe River Basin is not the key to the problem. On the other hand, in 2008, the global financial crisis swept through the local government, which is facing economic growth slowdown and rising unemployment rate, which is the central focus of everything to ensure stable economic development.
In some areas, economic development, no matter the so-called pollution to the environment, has led to the deterioration of pollution in the whole basin for decades. If you don't change it, it will only be "pollution-control-pollution" along the old roads, and in the end, the pollution will get worse and worse. “
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In the Yangtze River Delta, according to the field test of Nanjing Soil Research Institute, in 2006, only 40% of the soil was safe, and 30% of the soil was polluted in the vegetable base in the suburbs of Nanjing. According to the investigation of relevant departments in Zhejiang province, 82% of the total area of the province? I and II soils? According to the investigation, the remaining18% soil has been polluted to varying degrees. With the rapid development of industrialization, urbanization and agricultural intensification, and neglect of prevention and control, a large number of untreated wastewater is transferred to the rest of the soil system through various channels, which is the main factor of soil pollution. “
Recently, in Fengjiang, luqiao district, Taizhou City, Zhejiang Province, street 139 villagers were found, and the blood seriously exceeding the standard was under construction in the village. A battery business was the culprit of the key monitoring enterprise.
In the late 1980s, there were hundreds of millions of hectares of polluted areas, including hundreds of thousands of hectares. According to the Academy of Social Sciences of China Academy of Social Sciences, the soil types in China, which are heavily polluted by cadmium, are diversified. This is a arable land area polluted by heavy metals, ecology, arsenic, chromium, lead and heavy metals, accounting for one-fifth of the total area of the country every year. Due to heavy metal pollution and the reduction of more than100000 tons of grain, pesticides, antibiotics and pathogenic bacteria, it has also become the source.
Soil pollution, soil quality degradation, crop yield and quality, more serious soil-rich pollutants, toxic pollutants, such as mercury, cadmium contaminated land, other groups of rich crops fruit or livestock poisoning cases.
Such as Shenyang, Liaoning Zhangshi irrigation area soil and rice with excessive cadmium content, humans and animals can't eat it, because the soil irrigated by industrial wastewater for a long time is no longer cultivated land and can only be used for other purposes.
3。 Solid waste storage
In addition, the unreasonable application of chemical fertilizers and the spraying coverage of pesticides caused by pollution in this field are also quite serious.
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The local soil environment, environmental protection laws, regulations and policies, the demand of China market and soil pollution are facing a severe situation, and the problems faced by the whole country are serious soil pollution in different types in some areas, new and old pollutants, inorganic and organic compound pollution, and complicated ways of soil pollution (the first national work conference on prevention and control of soil pollution by the State Environmental Protection Administration was held in Beijing, The distribution of polluted areas is unclear, the foundation is weak, and the degree of pollution prevention and control measures and direction are based. The situation of local soil and water resources protection is not optimistic, and it faces many challenges. At the same time, the soil environmental standard system, which is very lacking in laws to prevent soil pollution, has not yet been formed. The main law to prevent soil pollution is the most important way to achieve soil, protect the environment and protect land quality, which is of great significance to maintain from a legal point of view.
First of all, there are gaps in relevant laws, regulations and soil pollution prevention and control, and there is a lack of effective legal, social, economic and environmental sustainable development. System, in China's current legal system, environmental soil pollution of agricultural land protection, land management, prevention and control of water pollution, air pollution prevention related laws and regulations, but basically a blank soil pollution prevention law (legal protection of certain laws sporadic provisions on the protection of agricultural ecological environment). It has played a positive role, but it is fragmented and unsystematic, lacking the operability of the specific legal system. With the rapid industrialization and urbanization of China, the agricultural land polluted by soil is still growing. The provisions restricted by the existing laws cannot effectively combat the soil pollution caused by modern agricultural technology and unreasonable land use, and cannot meet the actual needs of soil pollution prevention and control. The "vacuum" law will further increase, and the abuse of land resources will aggravate the problem of soil pollution (shallow analysis of legal problems to prevent soil). University professor? Xu Guanghua, from the Institute of Economic Management and Technology, Nanjing University of Science and Technology, pointed out that "there is a lack of a relatively unified regional environmental access and pollutant discharge standard, and there is a lack of relevant legal norms. The environment is in the Yangtze River Delta region, and the Yangtze River Delta region is the soft spot of the environment" and has encountered various environmental problems in this region? Economic development is usually very difficult, and the government can solve it reliably in order to cope with the increasingly serious environmental pollution. The relevant departments and cities in these two provinces must establish a regional environmental information sharing and publishing system as soon as possible, start the regional environmental monitoring and emergency linkage mechanism, and on this basis, speed up the legal norms of regional research and development to protect the environment. Therefore, on the basis of existing laws,
The prevention, management and law enforcement of soil pollution are chaotic. According to our existing legal system, the law protects the soil management system, and the implementation of multi-sector management is a combination of responsibility, which involves the responsibility of the government administrative department and soil pollution. In this system, the management of scattered power and responsibility of the main buildings is not conducive to centralized and unified management, and may lead to confusion (legal problems) in the management of soil pollution prevention and control. Analysis of different sources of soil pollution, the situation is complicated, so in addition to the responsibilities of the most closely linked growth environmental protection department, the regulatory power of environmental management is in many other departments, such as the Ministry of Finance, soil and water conservation, land and resource management (in certain cases, the competent authorities to prevent legal problems in rural areas of soil pollution), but the law does not give supervisory power, the administrative department of environmental protection law enforcement agencies and soil pollution control, The important problem of environmental law enforcement responsibility system is how to cooperate with law enforcement agencies, and at the same time, there is no provision, which leads to the bulls' failure to implement a specific soil and water protection and law enforcement, cross-enforcement, and even law enforcement agencies. Self-interest, reducing the overall benefits of soil protection, the overall requirements of damage, not designating departments, are completely different from the actual environmental management, administrative law enforcement, local soil protection, and the interests between the supervision and coordination of relevant laws. It will lead to many pollution problems that cannot be well solved, leading to strange quarrels and analysis of the power struggle between various departments (legal issues) of soil pollution prevention and control in China. It can be said that the existing multi-head management system, It not only seriously affects efficiency and controls pollution, but also wastes a lot of administrative resources in most places, especially in rural poverty-stricken areas. Due to economic backwardness, the strong desire to get out of poverty and rapid economic development, the economic development and environmental protection of most leading cadres sacrifice the main goal of environmental development plan (San Diego's legal countermeasures for soil pollution prevention and control in rural areas). Therefore, our soil pollution management and law enforcement are many.
Finally, we need to strengthen the judicial protection and the protection of soil environment. At present, in the case of serious pollution, although soil pollution occurs, there are few cases involving soil pollution litigation, only a few problems. Under the circumstances, the judicial relief of rural land in China is not difficult. First of all, according to the regulations on soil pollution remediation and compensation, enterprises are not subject to any constraints, even if the soil is polluted, it is difficult to hold them accountable. The event was in August 2006, a typical case of lead poisoning, Huixian County, Gansu Province. At that time, 368 people in Shuiyang Township of the county were in two villages, and the breakthrough of lead in blood was detected, including in 149-year, when the environmental protection department of Laoer found that the air and water pollution in two villages near the lead smelter in the local soil caused a major pollution source. The factory was later ordered to close, but how to effectively compensate the villagers 14. Fundamentally change the extensive growth mode that pollution harms public health and even the cost of their lives, but it is a thorny issue. (Qiu Lin, 1/5-star arable land, the situation of pollution prevention and control in China is grim, in order to improve the quality of soil environment. In addition, in rural environmental litigation, the real problem is that farmers of socially disadvantaged groups bear the litigation costs. They are victims of urban development and have long-term economic difficulties, and their income barely makes a living (Prevention and control of soil pollution in rural areas in Diego's legal countermeasures) At the same time, the long-term loss of farmers is a huge amount of soil pollution. In China's judicial practice, the object of litigation and the cost of litigation cannot be directly linked. The prepayment system of legal fees is possible for farmers, because they cannot afford the litigation cost and judicial protection (legal issues of prevention and control of rural soil pollution. ) 19991February 20, Xinggangji Village, Daqing City, Honggang District 13 Daqing City Court sued the defendant for compensation for the plaintiff's land pollution damage of 5 1843 1 13 farmers' land pollution situation of 06 yuan. But later, the farmers paid by the plaintiff's young crop compensation only knew about the lawsuit before 1999, but a petition appeared to find a settlement agreement between the town government, the bureau and the defendant unit, but it was on 1 1 4/month, 1999, not the actual performance in/kloc. Plaintiff's sampling is suitable for the identification of contaminated farmland. In 2000 1 month, the agricultural samples of Daqing Agricultural Bureau were sent to the provincial quality supervision and inspection center for testing, and the test results were organized by experts. The investigation by the Municipal Agricultural Bureau and the Agricultural Bureau showed that the crops had been seriously damaged in 20001year in May. The people under Article VII of the "Environmental Protection Law" and the State Committee for Environmental Protection of China focus on the unified supervision and management of the state, the local environmental protection management department and the administrative department of the people's government in this area. The people of the "Law on the Prevention and Control of Water Pollution" and China's 43, paragraph 2 of the implementation details, from 19991February to 20031February, the court finally mediated, and the court's hearing was closed four years later, and the defendant159. It is worth pointing out that the court of Daqing Intermediate People's Court ruled and rejected the plaintiff's request to take action on the ground beyond the limit of the plaintiff. The plaintiff refused to accept this sentence, but for many years, there was no income, no appeal fee, and farmers' uncultivated land. In order to safeguard the plaintiff's legitimate rights and interests and farmers' legitimate rights and interests, the agency paid the appeal fee of $ 10, 196.00 to get the final protection (land pollution damage is difficult to sue), BR /> On the basis of the existing legislation on the prevention and control of soil pollution, the prevention and control system of soil pollution, or the formulation of special laws and regulations, and the strengthening of legal supervision and management of soil pollution, the prevention and control of soil pollution should be an exquisite expansion, soil pollution irrigation, mining waste, municipal solid waste, fertilizers, pesticides and other pollutants, and pollution behaviors, so as to prevent soil pollution through legal means. In addition, laws and regulations should simplify the management system of soil pollution prevention and control, establish a dynamic soil pollution monitoring and evaluation system, develop specific soil pollution prevention and control planning system, soil pollution, environmental protection standards, and establish soil pollution emergency measures, systems and legal liability systems and other related systems.
(Analysis of Soil Pollution Prevention Law "(document).
Experience of soil environment protection and policy suggestions of typical models.
Potential soil pollution, irreversible, long-term characteristics and the seriousness of consequences, "prevention is more important than cure" should follow the basic principles of soil environmental protection, adhere to "putting prevention first, combining prevention with control, comprehensively treating unpolluted soil, taking preventive measures, controlling or eliminating pollution sources, and taking active control measures for contaminated soil to minimize pollution (research status and prospect), in order to protect our environment, soil pollution, it There is a big gap between the behavior of pollutants in soil-plant system, biogeochemical cycle, toxicology, metabolic pattern and epidemic situation of heavy metals, and the content of soil pollution control and management. Most treatment methods are still in the experimental stage, and considering the problems, such as the cost of treatment, mature methods can be applied under normal circumstances, and few people. Types of soil pollution prevention and control methods can be divided into the following four categories:
1。 Engineering measures (including foreign soil, soil, topsoil of cultivated soil, isolation, heat treatment, electrochemical method)
This is the effect measurement of free radicals, which is suitable for most pollutants under various conditions, but usually in a small area, which is more practical and expensive, and may lead to potential pollution. In recent years, groundwater or other media, sewage introduction, air pollution control technology has opened up new channels to prevent soil pollution in the process of soil remediation, such as magnetic separation technology, anion and cation substitution method (soil pollution control method).
< Measures/applications of chemical modifiers, inhibitors reduce pollutants in soil polluted by heavy metals, and add alkaline substances, such as water solubility, diffusibility and biological utilization, thus reducing the risk of labeled pollutants entering the food chain and reducing the soil ecological environment (). For example, heavy metals such as lime, slag and soil generate hydroxide precipitation. Heavy metals with larger exchange capacity are passivated in soil or bentonite is added to synthesize zeolite.
Biological control methods Biological measures, physical treatment and chemical treatment methods have incomparable advantages, and their advantages are mainly manifested in the following aspects: (1) Reducing the treatment cost, which is half that of only one third of the physical and chemical methods; (2) the treatment effect affects the environment, does not cause secondary pollution, and does not destroy the soil environment where plants grow; (3) it is very simple, on-site processing. Based on these advantages, it has become a popular research on soil pollution, bioremediation of soil pollution and application control technology in bioremediation. Biological measures to absorb or degrade soil? Use specific animal, plant and microbial pollutants. Corresponding measures, "environmental biotechnology" is a rising discipline. Pollution control measures in the field of biological application,1March, 989, the oil pollution in Alaska coast of the United States, using two groups of lipophilic microorganisms in the purification process, twice the speed. Early bioremediation technology used the main groups of microorganisms. Recently, phytoremediation has become a bright spot in the biological control measures of repair shops in three areas: plant fixation of plant volatiles and plant absorption of pollution. The research shows that the correct use of plants can not only remove organic matter in the soil environment, but also remove heavy metals and radionuclides. Super-enriched plants and super-accumulated good screening targets have become the pursuit of the environment. Start (review and prospect of soil and water conservation research). For example, the phytoremediation technology of cadmium contaminated soil, through a large number of screening studies, found that Cruciferae Brassica plants (Brassica. ) The accumulation of cadmium with strong absorption is characterized by various genotyping. Rape (Chinese cabbage) widely grown in China has certain species or genotypes, which may be crops with high cumulative filtration and low cadmium accumulation. Planting edible varieties (low absorption or low transmission), intercropping and crop rotation interaction (), in order to reduce the phytoremediation of cadmium absorption by crops, further research is needed (technical mechanism of phytoremediation of cadmium-contaminated soil by plants).
Agricultural measures /> Organic fertilizer to improve environmental capacity, control soil moisture, and choose appropriate forms of fertilizer and crop varieties to choose resistance.