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Statement 1: After the water is boiled, it should be boiled for 3 minutes to remove the chloride in tap water.
Truth: After the tap water is boiled, you should continue to boil, but you don't need to wait for 3 minutes, almost one or two minutes. Because tap water will be disinfected with chlorine when it is treated, it is beneficial to the volatilization of residual chlorine after boiling. Tap water itself contains some organic matter, which will form calcium in the process of boiling, but the calcium itself will not float away with the steam, but will always be in the water. The longer the combustion time, the more favorable it is for the precipitation of calcium in water.
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Statement 2: Thousands of boiling water is water that has been boiled on the stove for a night or a long time, and it is water that has been boiled repeatedly in the electric water heater. This kind of water will lead to the increase of harmful substances such as nitrite due to repeated boiling. Toxic nitrite can also cause hypoxia in the body, which can lead to coma, convulsion and even death in severe cases.
Truth: Repeated heating will not damage the water quality itself, but can only play the role of heating, sterilization and disinfection, and will not affect the water quality. As for the claim that nitrite causes cancer, there is no basis at all.
? Nitrite? It is the floorboard of a class of inorganic compounds, mainly sodium nitrite. Sodium nitrite is slightly salty, soluble in water, and similar in appearance and taste to salt. Widely used in industry and construction, but also allowed to be used as a colorant in meat products. Because of the high probability of food poisoning caused by nitrite, the state has strict control over the use of nitrite.
How can there be this substance in tap water? The reason is that the water people drink comes from natural surface water or groundwater. Because nitrate and nitrite are easily soluble in water, nitrate and nitrite in surface water may also slowly penetrate into groundwater; In addition, the nitrate contained in the water source may also be contaminated by microorganisms and become nitrite.
Although nitrite causes cancer, it is not easy to cause cancer through nitrite in water. Generally, the one-time safe intake of nitrite in human body is 0.2 mg per kilogram of body weight. In the Hygienic Standard for Drinking Water, it is stipulated that the content of nitrite should not exceed 10 mg/L, and it is safe to drink it once.
As for the statement that boiling water leads to an increase in nitrite content, it is only a guess. Because the authoritative media disclosed before, the nitrite content of boiled water is even lower than that of mineral water.
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Statement 3: The longest life span of a glass of water is 16 hours, and the total number of bacteria in overnight water is higher than that in tap water.
Truth: Water above 80 degrees is absolutely safe. Because temperatures above 80 degrees can kill microorganisms. When the water temperature drops below 60 degrees, the water environment is very suitable for the growth and reproduction of bacteria. However, there is no fixed time when it will deteriorate and become unfit for drinking, because it is also affected by the objective environment. For example, the outside temperature, the summer temperature is more than 30 degrees, the air humidity is high, bacteria multiply quickly, and it is easy to be polluted, causing human diarrhea. Therefore, it is best not to drink overnight water in summer, and it is best to put overnight water in a covered container in winter, such as a thermos bottle.
The shelf life of boiled water circulating on the Internet is only 16 hours. At present, there are no relevant experiments and data to prove it, but boiling water should not be kept for too long. Even if there is no shelf life, it is best not to drink boiled water after several days. It is recommended to drink bottled purified water within one week. When using the water dispenser to drink water, it is best to drink boiled water, because the number of microorganisms in cold water is likely to exceed the standard if the drinking water is left for a long time.
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Having said that, it's actually very simple. Tadpole Jun's suggestion is that boiled water is best to drink on the same day. Cover it if you can't finish eating it. It is best not to drink it if it is cold and cooked for more than 3 days. (Nobody likes to drink aged water ~ ~)
For more knowledge about drinking water, please poke >>& gt& gt72 What will happen to your body if you don't drink water for 72 hours?
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Author: Tadpole Jun