Why does water in essence represent essentially a chemical solution? What determines the composition of water?

Of particular importance for human life is the liquid form of water. Absolutely chemically pure water (without any impurities of chemicals and suspended particles) does not occur in nature. Passing through the atmosphere, water absorbs chemicals, dust particles and microorganisms from it. Settling on the surface of the earth, water flows into various bodies of water: rivers, lakes, seas. On its way, it additionally incorporates various substances. It turns out a kind of chemical solution, the composition of which is very complex and depends on the amount of absorbed chemicals, microorganisms and various particles.