When boiling water that contains nitrates, what happens to the concentration of nitrates?

When water that contains nitrates is boiled, the concentration of nitrates actually increases. This occurs because boiling water causes some of the water to evaporate, leading to a decrease in the overall volume of the water while the amount of nitrates remains constant. As the water volume decreases due to evaporation, the remaining nitrates are present in a smaller volume of water, resulting in a higher concentration of nitrates.

It's important to note that boiling does not remove or break down nitrates; instead, it concentrates them further. This realization highlights the need for alternate methods of treatment for nitrate contamination, such as reverse osmosis or ion exchange, instead of relying solely on boiling, which can inadvertently exacerbate the problem.