Land pollution refers to the pollutants produced by human activities enter the soil through various ways, and its quantity and speed exceed the capacity of the soil to hold and purify, so that the nature, composition and characteristics of the soil change, so that the accumulation process of pollutants gradually occupy the advantage, destroy the natural ecological balance of the soil, and lead to the natural dysfunction of the soil and the deterioration of soil quality.
1. Solid waste pollution: production and domestic waste are important sources of soil solid pollution. Industrial waste is piled up arbitrarily and untreated, and under the action of rain erosion, heavy metal elements will release the active components into the soil, which increases the harm to groundwater erosion. Industrial solid waste in our country comes mainly from the extractive industry. Chemical raw materials, chemical products, etc.
2. Chemical fertilizer and pesticide pollution: For a long time, the use of chemical pesticides is not scientific, not only pollute agricultural products, but also remain in the soil.
3. Sewage irrigation: Urban sewage and industrial wastewater contain nitrogen, phosphorus, potassium and other nutrients required by a variety of plants, and the rational use of sewage irrigation has a certain effect on increasing production. However, the discharge rate of China's sewage treatment industry is low, and the sewage contains a lot of toxic heavy metal pollutants. In addition, petrochemical. Chemical fertilizers, pesticides and other industrial wastewater can also cause phenol. Trichloroacetaldehyde and other organic pollution.
4. Atmospheric deposition pollution: harmful gases such as sulfur dioxide, fluoride, nitrogen oxides and hydrocarbons emitted by industry are the main sources of atmospheric acid deposition.
Hazards of soil pollution:
1. Soil pollution is harmful to human health.
Land pollution can cause pollutants to accumulate in plants (crops), and through the food chain to enrich the human body and animals, causing harm to human and animal health, causing cancer and other diseases. Longling Village, Guapo Town, Huaxian County, Shaanxi Province, is an independent natural village, located 8000 meters away from the county seat of Huaxian County, a dragon ridge shaped Tumao. Since the discovery of the first case of esophageal cancer in the village in 1974, a total of 55 people have died in the village, of which 30 died of cancer, the rest died of pulmonary heart disease, cerebrovascular disease, and so on, without a natural death. The population of the whole village dropped from 154 to 77, and the number of cancer patients and deaths increased year by year, and was younger. Longling Village has been shrouded in cancer for decades, and the soil pollution in the village was eventually found to be very serious.
2. Soil pollution has caused significant direct economic losses.
Crops are polluted and yields fall. At present, there is a lack of systematic survey data on the economic losses caused by various types of soil pollution. In terms of soil heavy metal pollution alone, the country has to reduce production of more than 10 million tons of grain every year, which is caused by heavy metal pollution. In addition, as many as 12 million tons of grain are polluted by heavy metals every year, with a total economic loss of at least 20 billion yuan.
3. Soil pollution causes other environmental problems.
After the soil is polluted, the pollution with high concentration of heavy metals is easy to enter the atmosphere and water body separately due to wind and water power, causing atmospheric pollution. Surface water pollution, groundwater pollution and other secondary ecological environment problems such as ecosystem degradation.
4. Soil pollution causes the decline of biological quality.
The soil in the suburbs of most cities in China is polluted to varying degrees, and there are many local foods. Such as vegetables, fruits and other agricultural products cadmium. Chromium, arsenic, lead and other heavy metals exceed the standard, close to the critical value. In addition to affecting the quality of food hygiene, soil pollution also has significant effects on other crop qualities.
Solutions to land pollution include:
1. Strengthen pollution control and reduce or eliminate the emission of pollution sources.
2. Rational use and protection of land resources, such as rational cultivation, crop rotation and other measures.
3. Promote environmental protection technologies and products to reduce soil pollution.
4. Strengthen monitoring and supervision to detect and deal with pollution problems in a timely manner.