Nitrite in repeatedly boiled water will increase. Nitrite is a strong blood poison. After it enters the human body in large quantities, it can oxidize the ferrous iron in hemoglobin into trivalent iron, which makes the blood lose its oxygen-carrying function and leads to hypoxia and suffocation. Nitrite has another dangerous potential toxicity. It can be materialized with amines in the stomach to synthesize nitrosamines, which are a strong carcinogen.
Because boiled water contains a certain amount of nitrite, the question of whether boiled water can be drunk cannot be generalized. It should be analyzed according to the specific situation. Old people say that according to customs, boiled water can't be drunk, which has no scientific reason. Because ancient sages have experienced such a thing, such as stomach pain and diarrhea after drinking boiled water repeatedly, they come to the conclusion that water cannot be drunk overnight. Over time, this.
Nitrite is a toxic substance, too much intake will destroy the oxygen carrying capacity of hemoglobin, leading to hypoxia in the body; Moreover, nitrite is a carcinogen, and long-term intake may cause cancer. Water itself contains nitrate, and people think that water will decompose into nitrite after many times of boiling, which is actually unreliable. Because some nitrates are very stable and will not decompose easily. Moreover, repeated heating of water will only reduce minerals, and has no effect on the water quality itself. After heating, it will also play a bactericidal role. As long as it is not cold boiled water for a long time, repeated boiling water will not affect our health, so it is also drinkable, and nitrite has not increased.
How long can cold boiled water be preserved? When the water temperature is above 80 degrees, it can kill microorganisms, and when the water temperature drops to 60 degrees, it is very suitable for bacterial reproduction, so at this time, try to drink the water before bacterial reproduction, preferably not more than 4 hours, so that you don't have to boil the cold water for a day.