Surely at least once in your life happen to boil water, you forget that you have done it and put the water to boil again.
Probably you are thinking that in this way you get rid of harmful substances or at least reduce their concentration, but the fact is that in this way the healthy minerals will become harmful.
Here’s what increases with prolonged boiling water:
The World Health Organization claims that the greatest danger in water for drinking is arsenic which involve poisoning, problems with organs and even cancer.
The high temperature converts nitrates into nitrosamines which are carcinogenic. They affect harm to the ovaries, intestines, stomach and can give rise to leukemia.
Some research suggests that fluoride affects the reduction of neurological and cognitive functions, reduces fertility and intelligence in children.