Water is the source of life. Without water, there is no life. The water content in adult human body accounts for 65% of body weight, and 80% of human blood is water. When the water content in human body decreases 10%, it will cause diseases, and when it decreases by 20% ~ 22%, it will die. Human life, industrial production and agricultural irrigation are all inseparable from water. However, with the development of industry and the increase of population, water pollution has become more and more serious, and has aroused widespread concern all over the world.
So, what is water pollution mud? People's Republic of China (PRC) Water Pollution Prevention Law promulgated by 1984 has a clear definition of "water pollution", that is, the phenomenon that the chemical, physical, biological or radioactive characteristics of a water body are changed due to the intervention of a certain substance, thus affecting the effective use of water, endangering human health or destroying the ecological environment, and causing the deterioration of water quality is called water pollution.
Water pollution has brought serious harm to our lives. Untreated urban domestic sewage, industrial sewage, farmland sewage, etc. When discharged into clean water, it will consume dissolved oxygen in the water, lead to hypoxia in the water, endanger the survival of fish, lead to the death of microorganisms that need oxygen, and seriously make the water black and smelly, accumulate toxins and endanger people and animals. In addition, wastewater and farmland sewage discharged from some chemical plants and pharmaceutical factories also contain a large number of toxic organic chemicals, which will poison aquatic organisms or cause ecological damage if they enter rivers and lakes. At this time, even human beings will suffer.
At present, more than 420 billion cubic meters of sewage is discharged into rivers, lakes and seas every year, polluting 5.5 trillion cubic meters of fresh water, which is equivalent to more than 14% of the total global runoff. Water pollution in China is also very serious. In China, about 36 billion tons of domestic and industrial wastewater are dumped into rivers, lakes and oceans every year, 95% of which are untreated. More than 90% of urban water bodies in China are seriously polluted, and nearly 300 million urban residents in China are facing the worldwide water pollution problem.
Water is the milk that nourishes human life. Water is limited, water is precious and water is non-renewable. Each of us should consciously establish the consciousness of saving water, tighten the faucet, save every drop of water, reduce and put an end to man-made water pollution. Now, scientific and rational use of water resources and water conservation have formed * * * knowledge in all countries of the world. 1993 65438+1October 18, the 47th UN General Assembly made a resolution to designate March 22nd as World Water Day every year. In a word, saving water, preventing sewage and ensuring the sustainable utilization of water resources are the common cause of mankind and everyone's responsibility!