How important is water? To what extent is our water pollution or lack of water in China now? 10

The main source of pollution.

Water pollution is mainly caused by pollutants produced by human activities, and it 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 data of the 1998 China Water Resources Bulletin, in this year, 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.

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. China does not monitor agriculture, and according to relevant data, 100 million hectares of arable land and 2.2 million hectares of grassland are used every year with 100 million tons of pesticides.

China is one of the countries with the most serious 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.

Every year, about 1 3 of China's industrial wastewater and more than 90% of domestic sewage are discharged into the water area without treatment, and more than 850 of the more than 1,200 rivers monitored in the country are 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 only the rivers that meet the national first-class and second-class water quality standards are accounted 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.

Answer: Hello, I am happy to answer for you, water pollution includes industrial wastewater, domestic sewage, agricultural sewage, industrial wastewater includes production wastewater, production sewage and cooling water, refers to the wastewater and waste liquid generated in the industrial production process, which contains industrial production materials, intermediate products, by-products and pollutants generated in the production process that are lost with water.

Domestic sewage refers to the wastewater discharged from residents' daily life, mainly in residential, building and public buildings and residential institutions, schools, hospitals, shops, public places.

Agricultural sewage pollution refers to the sewage and precipitation discharged from agricultural and animal husbandry production or irrigation water flowing through farmland, or water discharged through farmland leakage, and the large-scale use of agricultural fertilizers and pesticides has made agricultural production activities with a very small impact become the main water pollution.

(1) After water pollution that endangers human health, pollutants enter the human body through drinking water or food chain, causing acute or chronic poisoning. Arsenic, chromium, ammonium, benzo(a)pyrene, etc., can also induce cancer. Water contaminated with parasites, viruses or other pathogenic bacteria can cause a variety of infectious and parasitic diseases.

Water polluted by heavy metals is harmful to human health. Water and food contaminated by cadmium can cause kidney and bone lesions after human diet, and ingestion of 20 mg of cadmium sulfate will cause death. Poisoning caused by lead, causing anemia and nervous disorders.

Hexavalent chromium is very toxic, causes ulcers, and has carcinogenic effects. Drinking arsenic-containing water can cause acute or chronic poisoning. Arsenic inhibits or inactivates many enzymes, causing metabolic disorders, keratinization, and cancer.

Organophosphorus pesticides can cause neurotoxicity, and organochlorine pesticides will accumulate in fat, causing harm to the endocrine, immune function and reproductive function of humans and animals. Most of the fused aromatic hydrocarbons have carcinogenic effects. Cyanide is also a highly toxic substance, and after entering the bloodstream, it binds to the cell's pigment oxidase, interrupting breathing, causing respiratory failure and suffocation.

We know that 80% of the world's diseases are water-related. Typhoid, cholera, gastroenteritis, dysentery, and infectious liver are the five major human diseases, all of which are caused by the uncleanness of water.

2) After the water pollution of industrial and agricultural production, more treatment costs must be invested in industrial water, resulting in waste of resources and energy, and the water requirements for food industry are more stringent, and the water quality is unqualified, which will bring production to a standstill. This is also a factor that the efficiency of industrial enterprises is not high and the quality is not good. The use of sewage in agriculture reduces crop yields, reduces quality, and even harms people and animals, pollutes large areas of farmland, and reduces soil quality.

The consequences of marine pollution, such as oil pollution, which kills seabirds and marine life, are also severe.

3) The hazard of eutrophication of waterUnder normal circumstances, oxygen has a certain solubility in water. Dissolved oxygen is not only a condition for the survival of aquatic organisms, but also an important reason why natural water has the ability to self-purify by participating in various redox-reduction reactions in water and promoting the transformation and degradation of pollutants. The discharge of domestic sewage containing a large amount of nitrogen, phosphorus and potassium will reduce a large amount of organic matter in the water to release nutrients, promote the growth of algae in the water, the growth of plants, the poor ventilation of the water body, the decline of dissolved oxygen, and even the appearance of an oxygen-free layer.

As a result, a large number of aquatic plants die, the water surface turns black, and the water body stinks to form "dead lakes", "dead rivers", "dead seas", and then turn into swamps. This phenomenon is called eutrophication of water. The eutrophication water has a large odor, dark color, and many bacteria, and the water quality is poor, and it cannot be used directly, and a large number of fish die when the water is interrupted.

4) The harm of drinking water pollution: the impact of common drinking water quality items on human healthLead: harmful to the kidneys and nervous system, highly toxic to children, carcinogenic has been proven cadmium: acute damage to the kidneys.

The current situation of water pollution in China is not optimistic, relevant data show that about 3.6 million tons of domestic sewage and industrial wastewater flow into rivers, lakes and seas in China every year, 95% of which have not undergone any treatment, and 1?500 million tonnes of fecal sewage. More than 90% of the country's urban waters are seriously polluted, and nearly 300 million urban residents are facing the worldwide problem of water pollution.

According to the 2007 Bulletin on the State of China's Environment, surface water pollution remains serious across the country. The seven major river systems are moderately polluted, among which the Pearl River and the Yangtze River have good overall water quality, the Songhua River is slightly polluted, the Yellow River and Huai River are moderately polluted, and the Liao River and Haihe River are severely polluted.

For example, the Zhangze Reservoir, the main source of drinking water for 300,000 people in Changzhi City, Shanxi Province, is no longer in use due to severe pollution, and it has been forced to build another water plant to divert water from long distances. The water of the Zhanghe River is seriously polluted, the water sample of the river section of Xiangyuan County is black, a variety of toxic substances in the water float but do not sink, the chemical oxygen consumption exceeds the standard by 100, the biochemical oxygen demand exceeds the standard by 50, and the ammonia nitrogen content exceeds the standard by 667. Volatile phenol exceeds the standard by 16 percent

7. Fluoride exceeds the standard 20. In Xiangyuan County alone, more than 10,000 people drink the river water, and all the people who drink the river water in the two townships feel the peculiar smell, and 40 percent of the drinking people suffer from intestinal diarrhea, powdered teeth, and tooth loss.

Among the 28 national monitoring key lakes (reservoirs), 2 meet the second-class water quality, accounting for 7?1%；6 in the third category, accounting for 21?4%；4 of the four categories, accounting for 14?

3%；5 of the five categories, accounting for 17?9%；11 were inferior to the fifth category, accounting for 39 percent3%。

Among them, Taihu Lake: the overall inferior five categories, and the water quality of the rivers around Taihu Lake is generally moderately polluted; Dianchi Lake: Generally inferior five categories, the water quality of the rivers around Dianchi Lake is generally heavily polluted; Chaohu:

In general, there are five categories, and the water quality of the rivers around Chaohu Lake is generally heavily polluted; Other large freshwater lakes: Jingpo Lake, Dongting Lake, Poyang Lake and Xingkai Lake are four categories, Nansi Lake is five categories, and Baiyangdian, Dalai Lake and Hongze Lake are inferior five categories; Inner lakes in the city: In addition to Kunming Lake (Beijing), West Lake (Hangzhou), East Lake (Wuhan), Xuanwu Lake (Nanjing) and Daming Lake (Jinan) are all inferior to the fifth category.

The water quality of coastal waters in China is generally slightly polluted. Most of the offshore areas are clean; The water quality in the open sea area is good. Coastal waters of the country.

The proportion of Class I and Class II seawater is 62?8%, down 4% from the previous year9 percentage points; The third category is 11?

8%, up 3?8 percentage points; The fourth category and the inferior four categories are 25?4%, up 1?

1 percentage point. Among the coastal waters of the four major sea areas, the coastal waters of the South China Sea and the Yellow Sea have good water quality, but the Pearl River Estuary and Jiaozhou Bay are heavily polluted. The Bohai Sea is slightly polluted, but Liaodong Bay and Bohai Bay are heavily polluted. The East China Sea is heavily polluted, and the Yangtze River Estuary and Hangzhou Bay are heavily polluted. Red Tide:

A total of 82 red tides occurred in the whole sea. Of these, 25 were toxic red tides. The specific distribution is 7 times in the Bohai Sea, 5 times in the Yellow Sea, 60 times in the East China Sea, and 10 times in the South China Sea. It covers an area of 11,610 square kilometers, of which 1,906 square kilometers are toxic red tides.

The red tide disaster caused a direct economic loss of 6 million yuan throughout the year.

This paper makes a brief analysis of the prevention and control of urban domestic sewage in China, and on this basis, the principles and methods that can be followed in the prevention and control of urban domestic sewage are proposed.

1. Overview of urban domestic sewage.

Among all the natural elements that sustain human existence, economic construction and social development, the importance of water cannot be overstated. However, with the acceleration of industrialization and urbanization, the world is facing the challenges of water shortage and serious pollution.

China is particularly serious, is one of the world's 13 water shortage countries, more than 600 cities in the country is currently about half of the city water shortage, the deterioration of water pollution has made the water shortage worse: China's rivers and lakes are generally polluted, 75% of the country's lakes have varying degrees of eutrophication; 90%

Urban waters are seriously polluted, with 60%-70% of the total water shortage in southern cities

is due to water pollution; According to the groundwater survey of 118 large and medium-sized cities in China, 115 cities have been polluted, of which about 40% are severely polluted.

Water pollution reduces the use function of water bodies, aggravates the shortage of water resources, and has a negative impact on the implementation of China's sustainable development strategy.

China's water pollution mainly comes from two aspects, one is the excessive discharge of industrial wastewater from industrial development, and the other is the serious lack of urban sewage discharge and centralized treatment in urbanization, and a large amount of domestic sewage directly enters the water body without treatment, causing environmental pollution.

In recent years, although industrial wastewater has been treated and reduced, urban domestic sewage has increased unabated, accounting for more than 51% of water pollution. According to the monitoring of the environmental department, in 1999, nearly 80 percent of the country's domestic sewage went directly into rivers, lakes and seas without treatment, and the annual sewage discharge reached 40 billion cubic meters, causing more than one-third of the country's water areas to be polluted.

With the development of industry and the continuous expansion of the population, China is facing a very severe water pollution situation, and the water quality in some areas has even continued to deteriorate.

1. The eutrophication level of lakes in China has been reached, and the area of lake reservoirs in eutrophication and mesotrophic states accounts for the total area of lake reservoirs. Environmental monitoring showed that the eutrophication degree of large freshwater lakes was further aggravated.

The main pollutants are total phosphorus and total nitrogen. The western half of Chaohu Lake and Dianchi Lake are heavily polluted. The permanganate index of Taihu Lake is high, and the pollution of the river channel into the lake is heavy.

Sudden accidents occur from time to time in Hongze Lake.

2. According to the statistics of 110 key river sections of the country's seven major river systems and inland rivers, 32 percent of them meet the "Surface Water Environmental Quality Standards," 29 percent of them belong to the third category, and 39 percent of them belong to the category. The main pollution indicators were ammonia nitrogen, permanganate index, volatile phenols and biochemical oxygen demand. The downstream sections of large and medium-sized cities are generally polluted by coliform bacteria.

3. In recent years, the inorganic ammonia and inorganic phosphorus in the coastal sea areas have generally exceeded the standard, the pollution degree has increased, the nutrient content of local sea areas has exceeded the national water quality standard of Class 3, and the oil pollution has been reduced, but the pollution in the Pearl River Estuary, Dalian Bay, Jiaozhou and other sea areas is still serious. The frequency and area of red tides in China's coastal waters have increased.

The first thing that affects is the organisms near the water source, of course, including us humans, everything has a causal cycle, and the sins planted by human beings are borne by human beings.

Among the water pollution caused by human production activities, the water pollution caused by industry is the most serious. For example, industrial wastewater, which contains many pollutants and complex composition, is not only difficult to purify in water, but also difficult to treat.

Industrial wastewater is the most important cause of water pollution caused by industrial pollution. It accounts for the majority of pollutants emitted by industry. The pollutants contained in industrial wastewater vary greatly depending on the type of plant, and even the quality and quantity of pollutants contained in similar factories with different production processes are different.

In addition to the direct injection of wastewater into water bodies to cause pollution, solid waste and exhaust gases can also pollute water bodies.

Agricultural pollution is first caused by the loosening of the land surface by farming or land reclamation, and when the soil and topography are not stable, a large amount of sediment flows into the water, increasing the suspended solids in the water. Another important reason is that the use of pesticides and fertilizers has been increasing in recent years, and only a small amount of pesticides and fertilizers used are attached or absorbed, and most of the rest remain in the soil and float in the atmosphere.

The source of urban pollution is caused by the concentration of urban population, and the pollution of water bodies caused by urban domestic sewage, garbage and exhaust gas. The pollution of water bodies by urban pollution sources is mainly domestic sewage, which is a mixture of various sewage produced in people's daily life, including the sewage discharged from kitchens, washing rooms, bathrooms and toilets.