The main sources of water pollution are industrial waste, the use of agricultural pesticides, fertilizers, and domestic use. Water is considered polluted when it can no longer be used for its natural function as hydration, or because its chemical or biological properties have been radically altered
Overall, water loses its potability for everyday consumption by way of domestic, industrial or agricultural activities. Approximately 70 % of the Earth’s sweet water used is for agriculture, another 20 % is used by the industry and the remaining 10 % goes to domestic use.
Since the beginning of civilization, the sea has effectively worked as a natural spillway ensuring biodegradation and absorption of pollutants in the purification of sewage. For the last 100 years, increasingly frequent imbalances have endangered the marine environment due to accumulation of pollutants.
Water makes up two-thirds of the total weight of our body and is an essential element of life on the planet. Water covers about 70 % of the surface of the Earth which is a truly great volume. However, keep in mind that the planet's water is unique and can´t be reattached. It is true that water can be "made" through a process called hydrolysis, but it requires a lot of energy. Thus, it is very expensive, and impossible to rely on for the quantities that humanity requires.
Among the many properties of water, one of the most important is its melt ability. Pollutants such as chemical residues, gasoline or oil can contaminate the water surface and soil when they are mixed into some stage of the water cycle. Because the molecules are constantly moving in their liquid and gaseous states, water transports pollutants from one part to the other on the planet, whether or not there are dissolved or suspended contaminants. In other words, the pollutants will travel around the world many times.
Chemical pollution affects us by way of organic products such as anionic detergents, fatty acids and inorganic form of sulfates, phosphates, nitrates, chlorides and bicarbonates. Several of the pollutants that have a toxic effect on the body are pesticides, hydrocarbons, arsenic, mercury, lead, selenium and cadmium.