Drinking overnight water is not good for health. Although the tap water is disinfected and filtered, there are still some bacteria. When the water is boiled overnight and at 37 ℃, it is easy for bacteria to grow and reproduce. At the same time, the content of nitrite in the water will rise overnight. Drinking this kind of water is easy to cause disease. Therefore, drinking a pot of water for three days is a bad habit.
No overnight water
Many people have a cool bottle of water, which can be drunk at any time. However, this convenience may bring health risks. If you don't finish drinking that day, be sure to pour it out.
This is because the nitrogen-containing organic matter in the long-standing boiled water will be continuously decomposed into nitrite, and at the same time, the intervention of microorganisms will inevitably accelerate the decomposition of nitrogen-containing organic matter. The harm of nitrite to the body is well known. It has a strong ability to combine with hemoglobin in the body, which will hinder the normal oxygen transport function of the blood. Therefore, it's better to drink all the boiled water on the same day.
In addition, many families are used to drinking bottled water now, and the bottled water that seems to be well sealed should also be consumed within three or four days. Because the barreled water has been opened for a long time, bacteria will slip in along the water inlet, and the water dispenser will form a negative pressure when it comes out of the water, and it is inevitable to inhale part of the air, and the bacteria and microorganisms in the air will also 'take advantage of the emptiness'. If you don't finish drinking in a short time, the bacteria will exceed the standard, and the purified water will no longer be pure.
Boiling water takes three minutes
Water needs to boil for 3 minutes before drinking, because drinking water that is not completely boiled is easy to get cancer. People in boiled water cities drink tap water. After ordinary river water is sent to the waterworks, it needs to be chlorinated to remove microorganisms and other impurities. But at the same time, chlorine interacts with the residual organic matter in water, which will form toxic carcinogenic compounds such as halogenated hydrocarbon and chloroform.
The results show that the content of halohydrocarbon and chloroform is closely related to the change of water temperature and the duration of boiling. When the water temperature reached 90 ℃, the content of halogenated hydrocarbon increased from 53 micrograms per liter to 191 micrograms, and the content of chloroform increased from 43.8 micrograms per liter to 177 micrograms, which were two times higher than the national standard. When the water temperature rises to 100 ℃, the content of halohydrocarbon and chloroform will drop to 110 μ g and 99 μ g respectively, which still exceeds the national standard. If boiling continues for 3 minutes, the content of halohydrocarbon and chloroform will be reduced to 9.2 μ g and 8.3 μ g respectively, then it will become safe drinking water.
Of course, boiling water is not the longer the better, because the longer the water is burned, there are no volatile harmful substances and nitrites in the water, which will be concentrated due to the evaporation of water, and the content is relatively high. Drinking such water is also harmful to the body.
No repeated boiling of drinking water
Reboiled boiling water will cause the content of nitrite in the water to exceed the standard. As we all know, the excessive or excessive nitrite in the water can cause people to be tired, tired, drowsy, comatose, blue and purple all over the body, blood pressure drop, abdominal pain, diarrhea, vomiting, and malignant diseases for a long time. The way to prevent boiled water pollution is very simple: resolutely put an end to the reuse of boiled water, and repeatedly boil. In particular, the five types of boiled water mentioned below are not drinkable.
1. After burning on the stove for a whole night or a long time, the boiled water is not cold or hot when drinking;
2. The boiled water in the automatic water heater that is re boiled overnight;
3. Residual boiled water that has been repeatedly boiled for many times;
4. The boiling water not in the same day in the thermos bottle;
5. Boiled water left over from steamed food.
Boiled water should not be drunk after more than three days
If water is stored for a long time, it will be infected by bacteria to produce nitrite. Once a large number of nitrite enters the human body, it can cause tissue hypoxia, nausea, vomiting, headache, palpitation and other symptoms, and even death due to hypoxia. Nitrite can also form nitrosamines in human body and promote the development of liver cancer and gastric cancer. When the boiling water in the thermos changes temperature, the bacteria will propagate faster and the reduced nitrite will be more.