Polluted water will reach human body through drinking or food chain, which will eventually lead to acute or chronic poisoning. Common ones are methyl mercury poisoning, cadmium poisoning, cyanide poisoning and other metal poisoning, organic poisoning and pesticide poisoning. A large number of elements such as lead and barium will also pose a threat to the human body.
Second, carcinogenicity.
According to relevant statistics, there are more than 2,000 kinds of organic compounds in water bodies around the world, among which 769 kinds are found in drinking water, including 26 kinds of carcinogens, 8 kinds of carcinogens/kloc-0 and 45 kinds of mutagens. Water also contains a lot of toxic inorganic substances and heavy metals, such as chlorinated hydrocarbons produced in the process of tap water treatment. Different carcinogens will stimulate different cancer cells to varying degrees and cause diseases. If residents drink substandard water containing these substances for a long time, it will greatly increase people's cancer rate and busy death rate.
Third, water-borne infectious diseases.
Biological pollutants such as feces discharged from domestic sewage enter the human body, which will greatly increase the probability of people suffering from bacterial intestinal infectious diseases, such as typhoid fever, dysentery and cholera. According to the statistics of the World Health Organization, more than 5 million people die each year from infectious diseases caused by water pollution such as cholera and dysentery. As far as China is concerned, the number of people who die of diarrhea due to drinking unclean water reaches100000 every year. These data can vividly describe the harm of water pollution to people's health. Some parasitic diseases can also spread through water flow, posing a threat to human safety and health.
Fourth, indirect effects.
In addition to the above direct effects, the pollution of water resources will also cause a series of indirect effects. For example, some pollutants are controlled in a certain standard of water resources, although they are not directly harmful to human health, they will affect the taste and color of water, cause odor, abnormal color and other problems, and hinder the normal use of water. At the same time, the content of copper and zinc under the relevant standards will affect the growth and reproduction of microorganisms, thus reducing the self-purification ability of the whole water system and causing related problems.