Water quality and protection
Water is a unique and irreplaceable natural resource of limited quantities and uneven spatial and temporal distribution. All life forms and all human activities are more or less related to water, clearly showing the importance of the relationship with water. It is a necessary resource in households as drinking water, washing and food preparation, in agriculture for irrigation, and in industry it plays an important role in almost all industrial processes. Economic development and urbanization lead, on the one hand, to a large increase in water demand, and on the other hand to the threat to water resources and the aquatic environment. Water can thus become a limiting factor in development, a threat to human health and the sustainability of natural ecosystems. Until recently, there was a centuriesold illusion of water inexhaustibility, and the concept of minimum investments for the purification of used water and water protection in general appeared. Much of the water used is not purified before it is discharged into watercourses and thus pollutes the water mass and reduces the resources of drinking water. Providing enough drinking water is one of the world's most important issues today. Therefore, it is especially important for every society to balance these relations and devise policies and strategies for the regulation, exploitation and protection of water resources.