Natural water most times is not that simple water molecule (H20) often depicted in elementary chemical textbooks, but a complex mixture of many constituent with different concentrations. As water goes through its cycle and flows across the earth’s surface, it takes on minerals along with it, these minerals dissolve and contribute to the dissolved salts that are normally found in water. At the same time, organic matter from decomposed vegetation or from the soil with also dissolve and be saturated with dissolved oxygen, contain gases, like sulphur and nitrogen oxides etc, as such water contains many natural impurities.