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1. The analysis of the pollution problems and causes of contaminated soil in prominent areas is as follows:
According to incomplete surveys, there are 3,250 acres of contaminated farmland in the country, covering an area of ??about 1.5 million hectares, irrigation and sewage pollution, and solid waste piles. The total land occupied and destroyed is 2 million acres, accounting for more than one-tenth of the total area? There are 12 million tons of arable land in the country, and direct economic losses caused by heavy metal-contaminated food every year exceed 200 million yuan. There are, even in some areas, heavy soil pollution areas and high-risk areas where serious soil pollution exists.
Heavy metals are the density of one or more elements polluted by heavy metals, with densities ranging from 4.0 to 5.0 to 45, about 60 types. As and Se are non-metals, but are similar in their toxicity and some properties to heavy metals, heavy metal contaminants in the inclusions of Se, and selenium. Heavy metal pollution of the soil environment mainly refers to the biologically toxic mercury, cadmium, lead, chromium and metals, which also include, copper, cobalt, nickel, tin, V and other toxic heavy metals before the pollutants. Most people are concerned about lead, mercury, cadmium, lead, chromium, and arsenic, they are called the "Big Five" (Research Progress on Heavy Metal Pollution in Agricultural Soil). An informed source of heavy metals in soil is multi-channel, first of all, all contain heavy metals, different substrates, the process of forming substances containing heavy metals, the soil-forming parent soil is very different. In addition, human industrial and agricultural production activities have also caused heavy metal pollution in air, water and soil (Soil Heavy Metal Pollution Current Situation and Control Methods). In China, cadmium-contaminated land was involved in 25 counties in 11 provinces and cities. Cadmium-contaminated rice area reaches 44% of 670hm2 of cultivated land in Jiangxi Province. In Shenyang, the cadmium content of soil irrigated by wastewater in one county is as high as 130mg/kg. In Chengdu, cadmium-containing wastewater irrigated rice reaches 1?65mg/kg. The monitoring results of the National Environmental Monitoring Center and the Ministry of Agriculture from 1996 to 1998 showed that cadmium contamination of sewage irrigation accounted for 9% of the area? The largest heavy metal exceeding the standard is 56% agricultural cadmium, with an excess rate of 10% (Yifei Reclamation Project, 2001). Are there varying degrees of cadmium-contaminated cultivated soil in sewage-irrigated areas in China's major cities, including suburbs, Xi'an, and Shenyang? Soil cadmium pollution is particularly serious. For example, the cadmium content of farmland soil in Shenyang City is 0.88 mg/kg in the soil. The content of sewage irrigation area in Xi'an City is 0. Phytoremediation mechanism of soil cadmium contaminated soil (628 mg/kg)
Cricket Rock County soil pollutants magnesium and B soil magnesium content 43% of the pollution characteristics of serious pollution levels above the sampling point and 21.16 times. Only 211 and 238 sampling points reached the standard of clean, pollution-free B. It seems that the reason for the wider and more serious pollution level of the samples exceeds 50%, and its concentration in the soil of the sampling points is Xiuyan County Shitang, Pialing Wind source area. There are many bad soils in Xiyan County. Bearing in mind the process of broom meddling, short state-owned and townships, due to the release of mining and smelting enterprises, light burnt magnesium, heavy burnt magnesite and magnesite processing industry as the main body, a large number of picking and stripping Statistics of MgO, SO2 and other pollutants. The white powder that forms the landing surface of MgCX/vlgO? Magnesium (H0) 2 and other reaction products, a combination of large particles are dispersed in the soil. In the soil, magnesium sulfate and magnesium chloride are widely present in this area, forming a crust covering combined with the surface, fundamentally blocking crops. growth. Although crops grow in some areas, the greater threat to people's health and other organisms is the uptake of soluble Mg from the soil. B mine point source pollution caused by B pollution (soil pollution and its control strategies in mountainous areas of eastern Liaoning). Adsorption
The cadmium pollution of rice is significantly stronger than that of corn, soybeans and other crops due to various man-made factors, including mining and industrial, agricultural and traffic sources, such as varieties of heavy metals. Heavy metal contaminated soil (soil heavy metal pollution status and control method).
2.
? A large area of ??farmland soil is contaminated by sewage irrigation
Sewage irrigation and other wastes. In Shenyang Zhangshi Irrigation District, over 20 years, the pollution of irrigation sewage of more than 25 million hectares of cultivated land has led to severe cadmium pollution in rice fields. 2.13 million hectares of farmland in the suburbs of Tianjin are polluted due to sewage irrigation. Guangzhou suburban farmland is polluted, sewage irrigation 2 700hm 2, 1 333hm 2 soil contaminated sediment contains pollutants produced in the polluted areas, accounting for 46% of the suburban farmland. In the mid-1980s, a sample survey of Beijing's sewage irrigated area showed that about 60% of the soil contained 36% of brown rice pollution problems (The Current Situation of Soil Pollution in China and Its Countermeasures).
As early as the 1930s, it was recorded that wastewater from the Fushun refinery was discharged into the Hun River well for rice irrigation. In the 1950s, with the development of agricultural production in arid and semi-arid areas in the north, due to water shortages, in order to fully utilize the resources of sewage as fertilizer, the promotion of sewage irrigation areas played a positive role in promoting local agricultural and food production. In 1983, the sewage irrigation area was 2×1.06 million hm2. However, due to long-term sewage pollution of soil-crop irrigation systems have been exposed, in order to solve the soil environment, the application and development of sewage land treatment systems
The Yangtze River Delta, the Pearl River Delta, and the soil in typical areas of urban agglomerations in central and southern Liaoning Pollution investigation, comprehensive treatment pilot launch to repair contaminated soil and soil environmental quality standard system in typical areas, establish a complete risk assessment, complete the draft Soil Pollution Prevention and Control Law, starting from the types and types of pollutants, new technologies, new products and new Application failure effectively prevents new businesses, new pollutants, these pollutants will affect more persistent and more dangerous pollutants, the concentration of pollutants content, with the development of the economy, some pollutants gradually because they cannot degrade The cumulative increase is still very fast. For example, data show that in recent years, the mercury and cadmium content in the soil in Shanghai has increased by 50%, and in some areas, southern Zhejiang has excessive copper persistent organic pollutants in the soil. , the detection rate of heavy metals such as zinc reaches 100%.
According to reports, the Liaohe River Basin is a traditional industrial and mining area in China with convenient transportation and rich mineral resources, coal, oil, etc. Steel, mining, industrial economic structure is long-term, inefficient resource utilization, pollution, high intensity, low pollution sources, pollution control level, chemical industry, metallurgy, mining pharmaceutical and other industries are seriously polluting, outdated equipment and some enterprises, backward, polluting Insufficient prevention and control facilities, as well as weak environmental monitoring, early warning, emergency response and environmental law enforcement capabilities in the Liaohe River Basin, compliance with relevant legal provisions of environmental laws are more prominent in some aspects, and the phenomenon of lax law enforcement is insufficient punishment for pollution. The phenomenon cannot be effectively curbed.
Personnel also pointed out that soil and water pollution alternately affect each other. On the one hand, partial sewage irrigation causes soil shortage and pollution, and it takes a long time for the Liaohe River to solve this problem. , Industrial and agricultural water sewage irrigation causes a large amount of toxic and harmful substances to enter the soil and accumulate to a certain extent, exceeding the self-purification of the soil. The Liaohe River Basin, such as Anshan and Liaoyang, is a country famous in the industrial and mining fields, and exploits mineral resources. Caused by the development of very serious soil pollution all year round, heavy metals and toxic substances in the soil water erode, accelerating the pollution of river water.
Experts point out that the economic structure is based on resources and heavy industry, and the relative industrial production. The level of pollution is relatively high, and pollution control is difficult. Driven by economic interests, some companies do not install and operate pollution control facilities in place, and random discharge of sewage residues occurs from time to time, making it difficult for people to guard against; at the same time, the local government restructures the GDP The environmental awareness still turns a blind eye to the phenomenon of light pollution.
Articles Liaohe River pollution control faces a more important test - the ongoing impact of the current economic crisis is an urgent need to revitalize the old industrial base in Northeast China, on the one hand, the pollution of soil and water resources in the Liaohe River Basin Such problems are serious and huge pressure on one rule is not the key to the problem. On the other hand, local governments are facing slowing economic growth and rising unemployment during the global financial crisis in 2008 and are central to everything to ensure stability. Environmental governance faced by economic development has been ignored to make way for economic development.
The situation of pollution in the Liaohe River Basin over the past few decades has been heavy, and some people have expressed concern. In some areas, economic development has caused so-called environmental pollution over the past few decades. The pollution in the entire watershed will worsen. If you don't change, it will just be "pollution - treatment - pollution" along the old highway. In the end, the more treatment you have, the more pollution you will get, and the environment will get worse and worse. "
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In the Yangtze River Delta, according to field tests by the Nanjing Soil Research Institute in 2006, only 40% of the soil in the vegetable base in the suburbs of Nanjing was safe and 30% A survey by the relevant departments of Zhejiang Province shows that 82% of the province's soil is contaminated by industrialization, urbanization and agricultural intensification. With the rapid development and neglect of prevention and control, a large amount of untreated wastewater is transferred to the rest of the soil system through various channels, which is the main factor in the formation of soil pollution. "
Recently, in Luqiao District, Taizhou City, Zhejiang Province. In Fengjiang, 139 villagers in the subdistrict were found to have seriously exceeded the standard of blood in the village under construction, with a battery business as the key monitoring enterprise as the culprit.
20 In the late 1980s, millions of hectares of polluted areas were contaminated, ranging from hundreds to hundreds to thousands of hectares. According to the Chinese Academy of Social Sciences, China's soil types seriously contaminated by cadmium are diversified, which is a heavy metal pollution. Ecological, arsenic, chromium, lead and heavy metal pollution account for nearly 20,000 hectares of arable land area. About one-fifth of the country's total area is polluted every year due to heavy metal pollution and more than 100,000 tons of food, pesticides, antibiotics, and pathogenic bacteria have also become sources
Soil pollution, soil quality degradation, Crop yield and quality, more serious soil enrichment pollutants, toxic pollutants such as mercury, cadmium contaminated land, other groups of crops rich in fruit or livestock poisoning cases.
For example, the soil in the Zhangshi irrigation area of ??Shenyang and Liaoning contains rice with excessive heavy metal cadmium content. Humans and animals cannot eat it because the long-term use of industrial wastewater to irrigate the soil is no longer cultivated land and can only be used for other purposes.
3. Solid waste storage
In addition, the pollution in this area caused by the irrational application of chemical fertilizers and pesticide spray coverage is also quite serious
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Local The soil environment, protection and environmental protection regulations, institutional policies, the demand of the Chinese market and soil pollution are facing a severe situation. The problems faced by soil across the country are serious in some areas. Different types of soil pollution are serious. Soil pollution, the most existing New and old pollutants, inorganic and organic composite pollution, and soil pollution pathways are complex (the first nationwide soil pollution prevention and control work conference of the State Environmental Protection Administration was held in Beijing. The distribution of contaminated areas is unclear and the foundation is weak. Based on the degree of pollution prevention and control measures and direction, the situation of local soil and water resources protection work is not optimistic. It faces many challenges. At the same time, there is a very lack of laws to prevent soil pollution and a soil environmental standard system has not yet been formed. , the main law to prevent soil pollution is the most important way to achieve soil protection, environmental protection, and land quality protection, which is of great significance to maintain. From a legal perspective, the analysis of soil pollution situations includes the following three aspects :
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.
At that time, 368 people in 2 villages in Shuiyang Township, County, were tested for lead breakthroughs in their blood, including 149-year-old children. An investigation by the Environmental Protection Department found lead in the local soil near two smelters. Villages, air and water pollution create significant sources of pollution. The factory was later ordered to close, but how to effectively compensate the villagers14. But it is a thorny problem to fundamentally change the extensive growth model where pollution harms public health and even their lives. (Qiu Lin, 1/5 Star of Cultivated Land, China’s Pollution Prevention and Control Situation is Severe to Improve Soil Environmental Quality, Ministry of National Action, In addition, in rural environmental litigation, the real problem is farmers from disadvantaged groups in society burdened with the cost of litigation, they are victims of urban development and suffer long-term economic difficulties, their incomes barely make ends meet (Diego Legal Countermeasures for Soil Pollution Prevention and Control in Rural Areas), and at the same time, the long-term losses for farmers are Caused a huge amount of soil pollution, China's judicial practice, litigation subjects, litigation costs, cannot achieve direct contact, legal fee prepayment system, farmers are possible because they cannot afford the litigation costs and judicial protection (rural soil pollution prevention and legal issues of control.) On December 20, 1999, Daqing Municipal Court of Honggang District, Daqing City, Xinggangji Village 13 sued the defendant to compensate the plaintiff for land pollution damages of 51843113 yuan 06 "in the case of land pollution, Daqing Oilfield Co., Ltd. The company was liable in 1993, but later the plaintiff Qingmiao compensation was paid to the farmers. The lawsuit was only known to the farmers before 1999 due to the pollution of the land, but a petition appeared to find a settlement agreement between the town government, the bureau and the defendant unit, But on November 4, 1999, instead of the actual performance in December 1999, the plaintiff applied sampling to the contaminated farmland for identification. In January 2000, the Daqing Municipal Agricultural Bureau sent the agricultural samples to the Provincial Quality Supervision Bureau. The Supervision and Inspection Center tested the test results and organized experts to conduct an on-site investigation of secondary salinization of farmland soil slopes by the Municipal Agriculture Bureau. Expert opinion: In May 2001, it has caused serious damage to crops. Under Article VII of the Environmental Protection Law of the People's Republic of China, the National Commission for Environmental Protection of the People's Republic of China unifies the supervision and management of environmental protection work around the country, and the unified supervision and management of environmental protection work of the local environmental protection management department, the people's government In the case of implementation details of the "Water Quality Pollution Prevention and Control Law" of the People's Republic of China, Paragraph 2 of the People's Republic of China, from December 1999 to December 2003, the final court mediation, 2 courts Four years after the hearing, the defendant compensated the plaintiff 159,607.38 yuan for the loss, and the litigation costs were borne by the defendant. It is worth pointing out that the court of the Daqing Intermediate People's Court ruled that the plaintiff's request was overturned. Action. The plaintiff refused to accept this sentence, but had no income for many years and no appeal fees. The farmers had uncultivated land. In order to protect the plaintiff's legal rights and interests, the farmers' legal rights and interests were paid by the agency $ 10,196.00 can get the final protection (land pollution damage is difficult to litigate), BR/gt; based on the existing soil pollution prevention legislation, soil pollution prevention and control, control system, or the formulation of special laws and regulations , strengthen legal supervision and management of soil pollution, the prevention and control of soil pollution should be refined and expanded, soil pollution irrigation, mining waste, municipal solid waste, chemical fertilizers, pesticides and other pollutants, pollution-related acts, through the law means to prevent soil pollution. In addition, laws and regulations should streamline the management system for soil pollution prevention and control, establish a dynamic soil pollution monitoring and evaluation system, develop specific soil pollution prevention and control planning systems, soil pollution, and environmental protection standards, and establish soil pollution emergency measures and systems. and legal liability system and other related systems.
(Analysis of Soil Pollution Prevention and Control Law” (document).
Soil environment protection work experience and policy suggestions for typical models
Potential soil pollution, irreversible, long-term characteristics and severity of consequences, "prevention is better than cure" The basic principles that should be followed in the protection of the soil environment adhere to the principle of "putting prevention first, combining prevention and control, and comprehensively treating unpolluted soil, taking preventive measures to control or eliminate sources of pollution, and taking active control measures for contaminated soil to reduce pollution." To the minimum (research status and prospects) to protect our environment, soil pollution, which is quite difficult to control, behavior of pollutants in soil-plant systems, biogeochemical cycles, toxicology, metabolic patterns and research on heavy metals There is a big gap in the content of the epidemic, soil pollution control and management, and most treatment methods are still in the experimental stage. In addition, taking into account issues such as the cost of treatment, mature methods can be applied under normal circumstances. There are very few. Summary types of soil pollution prevention and control methods can be divided into the following four categories:
1. Engineering measures (including foreign soil, cultivated soil, topsoil, isolation, heat treatment, electrochemical methods )
This is a measurement of the effect of free radicals applicable to most contaminants and under a variety of conditions, but usually in a small area, is more practical and expensive, and can lead to potential In recent years, the introduction of groundwater or other media, sewage, and air pollution control technologies has opened up new channels to prevent soil contamination during soil remediation, such as magnetic separation technology, anion and cation substitution methods (soil pollution control methods). p>
lt; Measures/applications of chemical modifiers, inhibitors to reduce pollutants in heavy metal-contaminated soil, adding alkaline substances such as water-soluble, diffusible and bioavailable, thus reducing the entry of labeled pollutants into the food chain, And reduce the risk to the soil ecological environment (). For example: heavy metals such as lime, slag, and heavy metals in the soil generate hydroxide precipitation. The exchange capacity of heavy metals in the soil is passivated or bentonite is added to synthesize zeolite. Biological control methods have incomparable advantages over biological measures, physical treatments and chemical treatment methods. Their advantages are mainly reflected in the following aspects: (1) Reduce treatment costs. The treatment costs are equivalent to only one-third of those of physical and chemical treatments. Half of the method; ② Treatment effect, no impact on the environment, no secondary pollution, no damage to the soil environment for plant growth; ③ Very simple, on-site treatment. Based on these advantages, it has become a popular method of treating soil pollution. Bioremediation The study of applied control technologies in bioremediation. The use of biological measures to absorb or degrade specific animal, plant and microbial contaminants, an emerging field of "environmental biotechnology". As a pollution control measure, in March 1989, oil pollution on the coast of Alaska in the United States used two groups of lipophilic microorganisms to double the speed of the purification process. Early bioremediation technologies utilized the main group of microorganisms. Recently, phytoremediation has become one. Highlights of biological control measures in repair shops are in three areas: plant fixation of plant volatiles and plant absorption of contamination. Research shows that with the correct use of plants, not only remove organic matter in the soil environment, you can also remove heavy metals and radionuclides. Hyperaccumulators of plants and hyperaccumulators are excellent screening targets and have become a sought after environmental pursuit. Beginning (Review and Prospects of Soil and Water Conservation Research). For example, phytoremediation technology for cadmium-contaminated soil has been found through extensive screening studies that Brassica plants of the Brassicaceae family (Brassica spp.) have strong cadmium accumulation characteristics in various genotyping characteristics and are widely grown in Chinese rapeseed (Brassica rapa). ) There are certain species or genotypes that may be high-accumulating and low-cadmium-accumulating cadmium crops, planting food varieties (low absorption or low transmission), intercropping, rotation crop interaction () to reduce crop cadmium uptake by phytoremediation Research needs to do further research on the pollution characteristics (technical mechanism of phytoremediation of cadmium-contaminated soil in contaminated soil).
Agricultural measures /gt; organic fertilizers to improve environmental capacity, control soil moisture, and choose appropriate forms of fertilizers and select crop varieties with resistance