1. Spain Turkey Italy Germany Poland

2. Results of the research on the ion content in the natural waters in the individual countries.

3. Results of overall hardness KH and GH carbonate of natural waters from individual countries. The hardest water comes from Turkey.

4. “Water, has no taste, no color, no odor, it cannot be defined, art relished while ever mysterious. Not necessary to life, but rather life itself, it fills us with a gratification that exceeds the delight of the senses.” A. Saint-Exupery

5. Water, though commonly occurs in nature, has remarkable properties. Occurs in three states, which mekes it extremaly important in many biochemical processes taking place in the environment.

6. Water covers 70% of the surface of the globe, most of it is salt water, fresh water only takes up 2% of the Earth's surface, of which a significant part is in the form of the ice of Antarctica and Greenland. Results of the research on the ion content in the natural waters in the individual countries.

8. Class AA High-quality water for preservation of recreational and ecological interests. No discharges of any kind, no impoundment. Habitat natural and free flowing. Aquatic life as naturally occurs. Class A High-quality water with limited human interference. Impoundment allowed. Discharges must be of equal or better quality than receiving water. Habitat natural. Aquatic life as naturally occurs. Class B Good quality water. Discharges of well-treated effluents with ample dilution permitted. Habitat unimpaired. Ambient water quality sufficient to support life stages of all indigenous species. Only non- detrimental changes in community composition allowed. Class C Lowest quality water. Fishable and swimmable. Ambient water quality sufficient to support life stages of all indigenous fish species. Change in community composition may occur, but structure and function of community must be maintained.

9. As the results show, in all countries a high content of nitrates has been reported and, in Germany, Spain and Poland, the standard level has been exceeded. Nitrates in large concentrations are hazardous to your health, particularly for infants, potentially causing cyanosis-methemoglobinemia. The main source of inorganic nitrogen are sewages and used nitrogen fertilizers.

11. Water is a precious and irreplaceable substance and its presence on the globe is the guarantor of life and environmental development. Mismanagement of natural water resources can lead to irreversible degradation, which can minimize drinking water sources.

12. Water supply for the population all over the world is the main problem of this century. It is estimated that by 2025 the population will grow to 8 billion while water resources will remain the same. Therefore, it is important to take steps to find more effective ways of saving, treatment and management of its resources