-Hazards caused by water pollution
Some people say that the color of the earth is green, which breeds life and indicates the birth and future of mankind. I said, she is the cradle of life and the mother of mankind. She gave all her love selflessly to the children and grandchildren of mankind. She is indeed very big and has a vast territory, but it is not endless; She is really beautiful, beautiful, but she will not be young forever; She is indeed rich and rich in resources, but she is not inexhaustible.
Nowadays, the ecological environment of the earth has been seriously damaged by human activities. In particular, water pollution is more prominent. Water is the lifeblood of everything on earth. Water nourishes everything, breeds life and creates civilization. The distribution of water resources in China is extremely uneven. China's per capita water resources are less than 500 cubic meters, far below the internationally recognized critical value of per capita 1 000 cubic meters. Many large and medium-sized cities in the north stopped production or limited production due to lack of water, resulting in an annual loss of 654.38+0.2 billion yuan, and some cities in the south also experienced water shortage. At present, more than 300 cities in China are short of water, of which the serious water shortage is 108, and the water shortage is about100000 tons/day. Millions of people lack domestic water.
How is the water polluted? There are two main reasons: one is natural and the other is man-made. Due to the dissolution of various minerals by rainwater, a large amount of dust produced by volcanic eruption and wind erosion in arid areas falls into water bodies to cause water pollution, which belongs to natural pollution. A large number of untreated industrial wastewater, domestic sewage and various wastes are discharged into the water body, causing water quality deterioration, which belongs to man-made pollution. People usually say that water pollution mainly refers to the latter, which is also the most important.
Water pollution affects industrial production, increases equipment corrosion, affects product quality, and even makes production impossible. Water pollution affects people's lives, destroys ecology, directly harms people's health and causes great damage.
(1) is harmful to human health
After water pollution, pollutants enter the human body through drinking water or food chain, causing acute or chronic poisoning. Arsenic, chromium, ammonium, benzopyrene, etc. It can also induce cancer. Water polluted by parasites, viruses or other pathogenic bacteria will cause many infectious diseases and parasitic diseases.
Water polluted by heavy metals is harmful to human health. Water and food polluted by cadmium will cause kidney and bone diseases after people eat it. Ingestion of 20 mg of cadmium sulfate can cause death. Lead poisoning can lead to anemia and insanity. Hexavalent chromium is very toxic, which can cause skin ulcers and cause cancer. Drinking arsenic-containing water can cause acute or chronic poisoning. Arsenic inhibits or inactivates many enzymes, leading to metabolic disorders, skin keratinization and skin cancer. Organophosphorus pesticides can cause neurotoxicity, while organochlorine pesticides can accumulate in fat, which is harmful to endocrine, immune and reproductive functions of human beings and animals. Most polycyclic aromatic hydrocarbons are carcinogenic. Cyanide is also a highly toxic substance. After entering the blood, it combines with the pigment oxidase of cells, which interrupts breathing and causes respiratory failure, suffocation and death.
We know that 80% of the diseases in the world are related to water. Typhoid fever, cholera, gastroenteritis, dysentery and infectious liver disease are the five major diseases of human beings, all of which are caused by unclean water.
(2) Harm to industrial and agricultural production
After the water quality is polluted, industrial water must be put into more treatment costs, resulting in a waste of resources and energy. The food industry has stricter requirements for water. If the water quality is unqualified, it will stop production. This is also a factor of low efficiency and poor quality of industrial enterprises. The use of sewage in agriculture will reduce crop yield and quality, even harm people and animals, pollute large areas of farmland and reduce soil quality. The consequences of marine pollution are also very serious, such as oil pollution, which causes the death of seabirds and marine life.
(3) Harm of water eutrophication
Under normal circumstances, oxygen has a certain solubility in water. Dissolved oxygen is not only the survival condition of aquatic organisms, but also participates in various redox reactions in water, promoting the transformation and degradation of pollutants, which is an important reason why natural water bodies have self-purification ability. The discharge of domestic sewage containing a large amount of nitrogen, phosphorus and potassium leads to the degradation of a large number of organic substances and the release of nutrients in the water, which promotes the excessive growth of algae and plants in the water, makes the water body poorly ventilated, reduces dissolved oxygen and even appears anaerobic layer. A large number of aquatic plants die, the water surface turns black, and the water stinks to form a "dead lake", "dead river" and "dead sea", which in turn becomes a swamp. This phenomenon is called water eutrophication. Eutrophicated water has an unpleasant smell, dark color and many bacteria. This kind of water is of poor quality and can't be used directly, which prevents the fish from dying.
Since ancient times, human beings have been nourished by water and will continue to exist and develop in the future. No matter how the society progresses and the times develop, we can't exchange temporary economic development at the expense of the deterioration of the water environment, because that will have unbearable consequences for mankind and eventually lead to the extinction of all human civilizations. If the water environment problem in the past was caused by human ignorance, today, we have gradually realized the seriousness of the problem; If we say that water pollution and the destruction of water ecological environment are the result of our neglect of management, then today, we have taken a solid step on the road of water environment management; If the completed governance work has played a gratifying and positive role in curbing the deterioration of the water environment, then the future work will be more arduous and arduous, requiring more perfect legislative support, more extensive social participation and more lasting all-round investment. The present situation of water environment requires us to persist in governance, and the achievements have inspired us to be more confident in governance.
Water pollution control is more difficult than flood control and drought relief, because the occurrence of floods is accidental in time and limited in geography, while water pollution is everywhere. Floods and droughts are natural disasters. In the face of natural disasters, human beings are more United, more diligent, more helpful and more enthusiastic. The Yangtze River flood in 1998 is an example. Water pollution is a man-made disaster, which is caused by people. Pollution control will affect the interests of some people and involve all aspects of society. In short: water saving starts from scratch!