The three big killers of daily use of water

Human beings are facing the critical challenge of water pollution. Water pollution is mainly caused by the pollutants generated by human activities, including industrial pollution, agricultural pollution and life pollution. The increasing water pollution has posed a major threat to human survival and has become a major obstacle to the sustainable development of human health, economy and society. According to the world authority survey, in developing countries, 80% of all kinds of diseases are transmitted by drinking unhealthy water, and at least 20 million people are killed every year because of drinking unhealthy water. Therefore, water pollution is called the "world No. 1 killer".

Industrial pollution

Industrial waste water is an important source of water pollution. It has the characteristics of large volume, wide area, complex components, high toxicity, difficult to purify and difficult to handle. In eighteenth Century, Thames River in Britain was once completely lost of its value due to a large amount of industrial waste water. The famous European Rhine river caused the fishes in the river to disappear as a result of industrial pollution; 75% of Volga River's industrial waste water was discharged into the river without treatment; in China, there are more than 8 billion kilograms of nitrogen and 2 billion kilograms of phosphorus discharged to water each year. Among the most polluted rivers, Ganges river has about 2000000 tons of industrial waste discharged directly into rivers.

Agricultural pollution 

The main source of agricultural pollution is agricultural sewage, especially by irrigation or rainwater, the chemical pesticides and chemical fertilizers applied by the farmland are brought into the water body to cause pesticide pollution or eutrophication. In addition, the aquaculture industry uses antibiotics and hormones to ensure the production, but the water pollution caused by the residual harmful substances in the water is the common tap water which cannot be removed, so these hormones into daily life, become a hidden killer affecting the development of children. The discharge of agricultural pollutants has a great impact on the water environment. Its chemical oxygen demand emissions are 13 million 240 thousand and 900 tons, accounting for 43.7% of the total chemical oxygen demand. Agricultural sources are also the main sources of total nitrogen and total phosphorus emissions. Their emissions are 2 million 704 thousand and 600 tons and 284 thousand and 700 tons, respectively, accounting for 57.2% and 67.4% of the total emissions respectively. In the agricultural source pollution, the pollution of livestock and poultry farming is more prominent. The total nitrogen and total phosphorus of the chemical oxygen demand in livestock and poultry industry accounted for 96%, 38% and 56% of the agricultural sources respectively. Experts warn that agricultural pollution may cause more damage to water resources and environment than industrial pollution.

Life pollution

The main sources of life pollution are all kinds of detergent and sewage, waste and feces used in urban life. Most of them are non-toxic inorganic salts. There are more nitrogen, phosphorus and sulfur in the domestic sewage. The total amount of pollutants discharged is proportional to the total population. With the increase of urban population, everyone is the manufacturer of pollution, so the worse the water quality in large cities with population concentration; in addition, the polluted water in the upstream cities will also affect the water source of the downstream cities, causing "continuous pollution".