Water is essential for human life, but when we drink it, have we ever considered which types of water should not be consumed?
Raw water: Raw water contains various bacteria, viruses, and zoonotic parasites that are harmful to the human body. Drinking raw water can easily cause acute gastroenteritis, viral hepatitis, typhoid fever, dysentery, and parasitic infections. Especially nowadays, rivers, reservoirs, and well water are all contaminated to varying degrees by industrial waste, domestic sewage, and pesticide residues, making it even easier to get sick from drinking raw water.
Aged water: Commonly known as "stagnant water," this is water that has been stored for a long time without moving. Drinking this water often can slow down the metabolism of cells in minors, affecting physical development; in middle-aged and elderly people, it can accelerate aging. The incidence of esophageal and stomach cancer is increasing in many places, and according to medical research, it may be related to long-term consumption of aged water. Relevant data shows that the concentration of toxic substances in aged water also increases with the storage time.
Re-boiled water: This is water that has been boiling on a stove all night or for a long time, as well as water in an electric water heater that has been boiled repeatedly. Because it has been boiled for too long, this water contains high levels of non-volatile substances such as heavy metals like calcium and magnesium, and a high nitrite content. Drinking this water for a long time can interfere with gastrointestinal function, causing temporary diarrhea and bloating; toxic nitrites can also cause hypoxia in the body, and in severe cases, it can lead to coma, convulsions, and even death.
Steamer water: Steamer water is the leftover water from cooking foods like steamed buns. Especially when reused multiple times, the nitrite concentration in steamer water is very high. Drinking this water often, or using it to cook porridge, can cause nitrite poisoning; the scale that often enters the body with the water can also cause diseases of the digestive, nervous, urinary, and hematopoietic systems, and even premature aging.
Unboiled water: The tap water people drink is disinfected and sterilized by chlorination. Chlorinated water can separate into 13 harmful substances, some of which, like halogenated hydrocarbons and chloroform, are carcinogenic and teratogenic. When the water temperature reaches 90°C, the content of halogenated hydrocarbons increases from 53 micrograms per kilogram to 177 micrograms, exceeding the national drinking water hygiene standard by 2 times. Experts point out that drinking unboiled water increases the risk of bladder and rectal cancer by 21% to 38%. When the water reaches 100°C, these two harmful substances will greatly decrease with the evaporation of steam; if boiling continues for another 3 minutes, the water is safe to drink.
Re-boiled water: Some people are in the habit of re-boiling the leftover warm water in a thermos to save water, coal (gas), and time. However, this kind of "saving" is not advisable. Because the water is boiled again, the water evaporates further, and nitrite levels rise. Drinking this water often can cause nitrites to accumulate in the body and lead to poisoning.