The dangers of soil pollution

Hazards of soil pollution

1. Threat to national food security and food security. Soil pollution has brought about a decline in the quality of cultivated land, directly threatening the red line of 1.8 billion acres of cultivated land, leading to excessive levels of heavy metals in grain and agricultural products, affecting food safety.

2. Endangering human health. After heavy metals in the soil enter the human body through the food chain, they can cause cancer, teratogenesis, and mutagenesis.

3. Affect social stability. Soil pollution prevention and control involves the resettlement of workers from relocated industrial and mining enterprises, compensation for economic damage to farmers and damage to people's health, etc. If not handled properly, it will affect social harmony and stability.

Extended information

Methods to prevent and control soil pollution:

1. Change the concept and establish an ecological civilization assessment system. It is necessary to combine soil pollution prevention and control with the transformation of development methods and the development of modern agriculture. It is necessary to speed up the improvement of the evaluation index system for ecological civilization construction, promote its inclusion in cadre performance assessment, and further give full play to the "baton" role of assessment.

2. Mobilize the whole people and establish a public participation mechanism. Soil nurtures all things and is the foundation for the survival and development of the Chinese nation from generation to generation. It is necessary to form a general pattern of soil pollution prevention and control with nationwide mobilization, local responsibility, and departmental support. To prevent and control soil pollution and protect people's health, time and no time waits for us.

People's Daily Online - People's Daily: Prevent soil pollution? Protect people's health

Five major hazards of air pollution

Hazards of air pollution:

1. Harm to the human body: When the concentration of pollutants in the atmosphere is very high, it can cause poisoning of the human body, or worsen the condition, and even kill thousands of people within a few days.

2. Harm to plants: When the concentration of pollutants is very high, it will cause acute harm to plants, causing lesions on the surface of plant leaves, causing branches and leaves to wither and fall off.

3. Impact on climate: Air pollution will reduce the amount of solar radiation reaching the ground, increase atmospheric precipitation, and also increase the probability of acid rain. Acid rain can destroy large areas of forests and crops, and can cause Corrosion and fragmentation of paper products, textiles, leather products, etc. can cause the anti-rust coating of metals to deteriorate and reduce the protective effect, and can also corrode and pollute buildings.

The impact of air pollution source conditions:

The impact of air pollution source conditions can be viewed from two aspects: source strength and source height. Source intensity refers to the emission rate of pollutants. The concentration of pollutants is directly proportional to the source intensity, that is, the greater the source intensity, the more serious the pollution.

Source height refers to the height of pollution source emissions. Source height has a great influence on the concentration distribution of pollutants. The farther away from the pollution source, the lower the concentration of pollutants, but for elevated sources, the situation is more complicated. Taking the chimney as an example, the concentration of ground pollutants is very low very close to the chimney, gradually increases as the distance increases, reaches a maximum value, and then gradually decreases.

Main harms of soil pollution

The main harms of soil pollution are:

1. It leads to reduced crop yields and reduced quality of agricultural products.

2. Contamination of groundwater and surface water.

3. Affect the quality of atmospheric environment.

4. Harmful to human health.

Pollutants entering the soil mainly have different destinations such as fixation, volatilization, degradation, dispersion and leaching due to their different types and properties. Heavy metal ions are mainly ions that can stably adsorb soil inorganic and organic colloids.

Including ions specifically adsorbed by oxides and tightly bound to humins, as well as insoluble metal hydroxides, carbonates and sulfides produced in the chemical equilibrium of soil solutions, most of which will be fixed It is in the soil and difficult to eliminate; although some chemical reactions can alleviate its toxic effects, it is still a potential threat to the soil environment.

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1. Causes of soil pollution

1. "Three wastes" emissions from industrial and mining industries. Waste residues are leached by rainwater and pollute the soil, wastewater is polluted by rivers and farmland, and waste gases accumulate in the soil through atmospheric deposition.

2. Agricultural non-point source pollution. The excessive use of chemical fertilizers, pesticides, and mulch films has caused pollutants to remain in the soil for a long time. Livestock feed contains additives such as copper, zinc, and arsenic, and long-term use of livestock manure as organic fertilizer can also cause soil pollution.

3. Garbage surrounds cities and villages, polluting the soil.

2. Measures to prevent and control soil pollution

1. Change the concept and establish an ecological civilization assessment system.

The frequent occurrence of soil pollution incidents is one of the manifestations that my country's environmental capacity has reached a critical point. We must attach great importance to it and effectively change the development concept of GDP first.

2. Improve the system, revise laws and regulations, and improve various standards. my country's current soil environmental quality standards are imperfect and are still blank in some aspects. It is necessary to take people's health and sustainable development as the fundamental principles to comprehensively review, revise and improve soil pollution standards, restoration standards, sewage treatment standards, agricultural product and feed safety standards, etc. as soon as possible.

3. Deepen reforms and rationalize the soil pollution prevention and control management system. Soil pollution prevention and control work is managed by multiple departments and "multiple heads". Establish a unified coordination mechanism for soil pollution prevention and control, a total discharge control system in the river basin, and a compensation and compensation system for soil environmental damage.

4. Strengthen research and development and carry out major restoration projects. The control and remediation of soil pollution is difficult, physical and chemical methods are costly, and biological methods are time-consuming. It is necessary to encourage scientific research institutions to accelerate research on soil management and restoration technologies that are low-cost and easy to be promoted on a large scale, and to reward scientific researchers who have achieved significant results.

Baidu Encyclopedia-Soil Pollution

China Communist Party News Network-Qian Guanlin: Preventing and controlling soil pollution to protect people’s health

Main causes of soil pollution What is the reason?

Causes of soil pollution

1. Pollution of soil from sewage irrigation

Domestic sewage and industrial wastewater contain nitrogen, phosphorus and potassium and other nutrients needed by many plants, so rational use of sewage to irrigate farmland generally has the effect of increasing production. However, sewage also contains many toxic and harmful substances such as heavy metals, phenols, and cyanides. If the sewage is directly used for farmland irrigation without necessary treatment, the toxic and harmful substances in the sewage will be brought to farmland and pollute the soil. For example, industrial wastewater such as smelting, electroplating, fuel, and mercury compounds can cause pollution by heavy metals such as cadmium, mercury, chromium, and copper; industrial wastewater such as petrochemical industry, fertilizers, and pesticides can cause pollution by organic matter such as phenol, trichloroacetaldehyde, and pesticides.

2. Soil pollution caused by air pollution

The harmful gases in the atmosphere are mainly toxic waste gases emitted from industry. They have a large pollution area and can cause serious pollution to the soil. Industrial waste gas pollution is roughly divided into two categories: gas pollution, such as sulfur dioxide, fluoride, ozone, nitrogen oxides, hydrocarbons, etc.; aerosol pollution, such as solid particles such as dust, soot, and liquid particles such as smoke and fog. It enters the soil through sedimentation or precipitation, causing pollution. For example, the waste gas discharged from non-ferrous metal smelting plants contains heavy metals such as chromium, lead, copper, and cadmium, which pollutes nearby soil; factories that produce phosphate fertilizers and fluoride can cause dust pollution and fluorine pollution in nearby soil.

3. Soil pollution from chemical fertilizers

The application of chemical fertilizers is an important measure to increase agricultural production, but unreasonable use can also cause soil pollution. Long-term and large-scale use of nitrogen fertilizers will destroy the soil structure, cause soil hardening, deteriorate biological properties, and affect the yield and quality of crops. Excessive use of nitrate nitrogen fertilizer will cause feed crops to contain too much nitrate, which will hinder the transport of oxygen in the body of livestock, causing them to become sick and seriously lead to death.

4. The impact of pesticides on soil

Pesticides can prevent and control diseases, insects, and weeds. If used properly, they can ensure an increase in crop yields, but they are very harmful. Soil pollutants, improper application will cause soil pollution.

Except for part of the pesticides sprayed on crops being absorbed by plants or escaping into the atmosphere, about half is scattered on farmland. This part of the pesticides and the pesticides directly applied to the fields constitute the pesticides in farmland soil. basic source. Crops absorb pesticides from the soil and accumulate in roots, stems, leaves, fruits and seeds, harming human and livestock health through food and feed. In addition, while pesticides kill insects and prevent diseases, they also harm microorganisms, insects, and birds that are beneficial to agriculture, destroy the ecosystem, and cause indirect losses to crops.

5. Soil pollution by solid waste

Industrial waste and municipal garbage are solid pollutants of soil. For example, various agricultural plastic films are widely used as greenhouse and mulching films. If management and recycling are not good, a large number of residual film fragments will be scattered in the fields, which will cause "white pollution" of farmland. Such solid pollutants are neither easy to evaporate, volatilize, nor easily decomposed by soil microorganisms. They are pollutants that remain in the soil for a long time.

Soil pollution prevention and control

Soil pollution prevention and control are activities to prevent soil from being polluted and to improve and treat contaminated soil. Soil protection should focus on prevention. The focus of prevention should be on controlling the concentration and total amount of emissions from various pollution sources; conducting regular monitoring and supervision of agricultural water use to ensure that it meets farmland irrigation water quality standards; rational application of chemical fertilizers and pesticides, and careful use of sewage sludge and river mud. , pond mud; the use of urban sewage for irrigation must be purified; promote biological control and comprehensive control of pests, diseases, and weeds, and renovate mines to prevent mine poisonous pollution, etc. In terms of improvement and treatment, heavy metal polluters use soil discharge, soil improvement or chemical amendments, and change the redox conditions of the soil to convert heavy metals into insoluble substances and reduce their activity; organic pollutants such as trichloroacetaldehyde can be treated with Measures such as loosening the soil, applying alkaline fertilizer, plowing and drying the ridges, irrigation and flushing can be used to control it. Strengthen environmental legislation and management. For example, Japan regulates specific harmful substances such as cadmium, copper, arsenic, etc. according to soil pollution legislation. Any area that meets the following conditions is designated as a control area, and control measures need to be taken by the local government: areas where the cadmium concentration in brown rice exceeds or may exceed 1mg/kg; the copper concentration in paddy fields is extracted and measured with 0.1N hydrochloric acid, and exceeds 125mg/kg Areas; areas where arsenic concentration in paddy fields is above 10-20mg/kg.

Types of pollution

Air pollution

[airpollution] There is a large amount of dust, smoke, gas, fog, odor, smoke or steam in the outdoor atmosphere. One or more contaminants whose characteristics and persistence are sufficient to damage human health or animal or plant life.

Air pollution When the content of certain substances in the air exceeds the normal content, it will harm animals and plants and affect their survival. The normal contents of substances such as CO, NH3, SO2, H2S, Cl2, 03 and N02 in the atmosphere are all below one part per million, and have no obvious adverse effects on animals and plants.

However, since the 19th century, due to the development of industry and transportation, large amounts of the above substances have been discharged into the atmosphere, making air pollution increasingly serious, affecting the life activities of animals and plants and even human health. Some sources of pollutants come from nature, and some come from human activities. Among them, waste gas generated by industry and transportation is the main source of pollution. Can turn into water pollution and soil pollution.

Exhaust pollution

Air pollution caused by harmful gases emitted by cars. The main harmful gases are carbon monoxide, nitrogen oxides, hydrocarbons, sulfur dioxide, etc. Can cause photochemical smog, etc. The quantity and type vary due to factors such as gasoline type, vehicle load capacity, engine performance, road conditions, weather conditions, etc. Since automobile exhaust is at a high level in the human respiratory zone, exhaust pollution is very harmful to human health.

Combustion pollution

Common pollutants during the combustion process include carbon monoxide, sulfur dioxide, nitrogen oxides and smoke. Combustion also produces noise pollution, heat pollution and lead pollution.

The noise caused by combustion mainly comes from the intake duct, exhaust duct and burner. Controlling noise sources, attenuating transmission, using mufflers, etc. can reduce noise

Radioactive pollution

The main pollutant caused by radioactive substances is the emissions from nuclear industry enterprises , radioactive fallout produced by nuclear tests, natural cosmic rays, radioactive mineral deposits and natural radioactive isotopes, etc. It can cause harm to the human body through the food chain or directly.

Heavy metal pollution

Environmental pollution caused by heavy metals or their compounds. It is mainly caused by human factors such as mining, waste gas emissions, sewage irrigation and the use of heavy metal products. For example, Minamata disease and Itai-itai disease in Japan are caused by mercury pollution and cadmium pollution respectively. The degree of harm depends on the concentration and chemical form of heavy metals in the environment, food and organisms.

Radio frequency pollution

Environmental pollution caused by radio frequency electromagnetic radiation. Common sources of pollution are high-altitude television transmission towers, medium-short-wave and microwave transmitting equipment, high-frequency heating equipment, and short-wave or ultra-short-wave physiotherapy machines.

Soil pollution

The phenomenon of soil quality deteriorating due to contamination. Pollutants mainly come from sewage irrigation, pesticide application, fertilization, waste accumulation and atmospheric deposition. It not only hinders the development of agriculture, forestry, fishery and animal husbandry, but also affects human health.

Common soil pollution includes

1. Chemical pollutants. Including inorganic pollutants and organic pollutants.

The former include heavy metals such as mercury, cadmium, lead, arsenic, excess nitrogen and phosphorus plant nutrients, oxides and sulfides, etc.; the latter include various chemical pesticides, petroleum and its cracking products, and other types of organic synthesis products. .

2. Physical pollutants. Refers to solid waste from factories and mines such as tailings, waste rock, fly ash and industrial waste.

3. Biological pollutants. It refers to municipal garbage containing various germs and wastewater, waste and manure discharged from sanitary facilities.

4. Radioactive pollutants. It mainly exists in areas where nuclear raw materials are mined and nuclear explosions occur in the atmosphere. It is mainly composed of radioactive elements with long survival times in the soil, such as strontium and cesium.

Extended information

Soil pollution is hidden and lagging. Problems such as air pollution, water pollution and waste pollution are generally relatively intuitive and can be discovered through the senses. Soil pollution is different. It can often be determined by analyzing soil samples and detecting residues in crops, or even by studying the impact on human and animal health.

1. Cumulative

Pollution substances are generally more likely to migrate in the atmosphere and water than in soil.

2. Irreversibility

The pollution of soil by heavy metals is basically an irreversible process, and the pollution of many organic chemicals also takes a long time to degrade.

3. Difficult to control

If the atmosphere and water bodies are polluted, the pollution problem may continue to be reversed through dilution and self-purification after cutting off the pollution source.

4. High radiation

A large amount of radiation has polluted the land, making the contaminated land contain a kind of poison. This poison will make the plant unable to grow and stop growing!