First, aged water: commonly known as "stagnant water", that is, water that cannot be stored for a long time. Drinking this kind of water often will obviously slow down cell metabolism for minors and affect the growth and development of the body; Middle-aged and elderly people will accelerate aging; The incidence of esophageal cancer and gastric cancer is increasing in many places. According to the research of medical scientists, this may be related to drinking aged water for a long time. Relevant data show that the toxic substances in aging water also increase with the increase of water storage time.
2. Thousands of boiling water: Thousands of boiling water refers to the water that has been boiled on the stove for a night or a long time, and the water that has been repeatedly boiled in the electric water heater. Because this kind of water takes a long time to boil, the content of heavy metals such as calcium and magnesium and nonvolatile substances such as nitrite in the water is high. Drinking this water for a long time will interfere with people's gastrointestinal function and cause temporary diarrhea and bloating; Toxic nitrite can also cause hypoxia in the body, which can lead to coma, convulsion and even death in severe cases.
Third, boiler water: boiler water is leftover boiler water such as buns, especially boiler water that has been reused many times, and the nitrite concentration is very high. Drinking this water often, or cooking porridge with this water, will cause nitrite poisoning; Scale often enters the human body with water, and it can also cause digestive, neurological, urinary and hematopoietic diseases, and even cause premature aging.
Fourth, the water that can't be boiled: the tap water that people drink is chlorinated and sterilized. 13 A variety of harmful substances can be separated from chlorine-treated water, among which halogenated hydrocarbons and chloroform also have carcinogenic and teratogenic effects. When the water temperature reaches 90℃, the content of halogenated hydrocarbons increases from 53 micrograms per kilogram to 177 micrograms, which is twice as high as the national sanitary standard for drinking water. Experts point out that drinking raw water increases the possibility of bladder cancer and rectal cancer by 2 1%-38%. When the water temperature reaches 100℃, these two harmful substances will be greatly reduced with the evaporation of steam. If boiling lasts for 3 minutes, it is safe to drink.
5. Boil water again: Some people are used to boiling the remaining warm water in thermos bottles before drinking, in order to save water, coal (gas) and time. But this "saving" is not enough. Because water burns again and evaporates, nitrite will rise. If you drink this water regularly, nitrite will accumulate in the body and cause poisoning.