What are the 8 major polluted water resources and what are the main causes of water pollution?

The main causes of water pollution are twofold:

1: Natural pollution. It is due to the change of natural laws and the pollution of water sources by minerals in the soil.

2: Anthropogenic pollution. It is the pollution caused by human life and production activities, and the water pollution generally refers to man-made pollution. It includes industrial wastewater pollution, agricultural pollution, domestic sewage pollution, and water pollution caused by municipal solid waste.

Increasing water pollution has posed a major threat to human survival and security, and has become a major obstacle to human health, economic and social development. According to the world's authoritative survey, in developing countries, 80% of all kinds of diseases are transmitted by drinking unhygienic water, and drinking unsanitary water causes at least 20 million deaths worldwide every year, so water pollution is called"The number one killer in the world"。

Water pollution affects industrial production, increases equipment corrosion, affects product quality, and even makes production impossible. Water pollution also affects people's lives, destroys the ecology, and directly endangers people's health, causing great damage.

Water pollution is water that pollutes the environment by reducing or losing the use value of water caused by harmful chemicals. Acids, alkalis, oxidants, as well as compounds such as copper, cadmium, mercury, arsenic, benzene, dichloroethane, ethylene glycol and other organic poisons in sewage will poison aquatic organisms and affect drinking water sources and scenic landscapes. When the organic matter in the sewage is decomposed by microorganisms, the oxygen in the water is consumed, affecting the life of aquatic organisms, and after the dissolved oxygen in the water is exhausted, the organic matter is anaerobic decomposed, producing unpleasant gases such as hydrogen sulfide and mercaptan, which further deteriorates the water quality.

1) Industrial wastewater: Industrial wastewater is the main cause of pollution worldwide. Residual wastewater can be generated at all stages of the industrial production process. The industrial wastewater with greater impact mainly comes from metallurgy, electroplating, papermaking, printing and dyeing, tanning and other enterprises.

2) Domestic sewage: refers to people's daily life washing waste and boiling water and fecal and urine sewage. Sewage from medical units is a special type of domestic sewage, and the main hazard is to cause intestinal infectious diseases.

3) Agricultural sewage: mainly contains nitrogen, phosphorus, potassium and other chemical fertilizers, pesticides, manure and urine and other organic matter, and human and animal intestinal pathogens.

4) Others: The solid waste generated in the production process of the industrial and air tourism industry contains a large amount of inorganic and organic matter that is easily soluble in water, and the water body is polluted by rainwater.

Water pollution is mainly caused by pollutants produced by human activities, which includes three major parts: industrial pollution sources, agricultural pollution sources and domestic pollution sources.

Industrial wastewater is an important source of pollution in waters, which has the characteristics of large quantity, wide area, complex composition, high toxicity, difficult to purify, and difficult to treat. According to the 1998 China Water Resources Bulletin, the total amount of wastewater discharged in the country was 53.9 billion tons (excluding thermal direct current cooling water), of which 40.9 billion tons were discharged from industrial wastewater, accounting for 69%.

In fact, the amount of sewage discharged is far more than that, because it is difficult to calculate the amount of industrial sewage discharged by many township enterprises.

Agricultural sources of pollution include livestock manure, pesticides, fertilizers, etc. In pesticide sewage, one is high in organic matter, plant nutrients and pathogenic microorganisms, and the other is high in pesticides and fertilizers. According to relevant data, 100 million hectares of cultivated land and 2.2 million hectares of grassland are used every year.

China is one of the countries with the most severe punishment for soil erosion in the world, with an annual topsoil loss of about 5 billion tons, resulting in a large number of pesticides and fertilizers flowing into rivers, rivers, lakes and reservoirs with the topsoil, and the subsequent loss of nitrogen, phosphorus and potassium nutrients makes 2 3 lakes suffer from different degrees of eutrophication pollution, causing abnormal reproduction of algae and other organisms, causing changes in water transparency and dissolved oxygen, resulting in deterioration of water quality.

The main sources of domestic pollution are all kinds of detergents and sewage, garbage, feces, etc. used in urban life, most of which are non-toxic inorganic salts, and domestic sewage contains more nitrogen, phosphorus, sulfur, and more pathogenic bacteria. According to the survey, in 1998, China's domestic sewage discharge was 18.4 billion tons.

About 1 3 of China's industrial wastewater and more than 90% of domestic sewage are discharged into the water area without treatment every year, and among the more than 1,200 rivers monitored in the country, more than 850 are currently polluted, and more than 90% of the urban waters are also polluted, resulting in the extinction of fish and shrimp in many river sections, and the rivers that meet the national first-class and second-class water quality standards only account for. Pollution is moving from shallow to deep, groundwater and coastal waters are also being polluted, and the amount of water we can drink and use is decreasing imperceptibly.

The Daliao River is seriously polluted, the Haihe River system, the main stream of the Huai River and the main stream of the Yellow River are severely polluted, the Songhua River is moderately polluted, and the Yangtze River and Pearl River are second (also intensifying).

The seven major water systems in China are all polluted to varying degrees, so please rank them in order of the severity of the pollution.

In order: Liao River, Hai River, Huai River, Yellow River, Songhua River, Pearl River, Yangtze River.