Natural mineral water is a product of the water cycle, which means that it is rain water that has been both enriched with minerals and cleaned thanks to many years of filtering through soil and rock layers. Some Austrian mineral water deposits are found up to 200 and more metres below the Earth’s surface. Mineral water contains all the natural elements of water (minerals and trace elements, also natural radionucleids and heavy metals), but also foreign substances, which are substances or derivates (through chemical or organic degradation) that get into the water as the result of human activities.
Contamination could have many reasons, beginning with poor well building (surface water infiltrates through the borehole), contamination during bottling, (e.g. anticorrosive), infiltration via agricultural land (infiltrated through sediment layers over decades), industrial and household chemicals, pharmaceutical substances and food ingredients and additives, as well as contaminated sites -- e.g. artificial radionucleids (cause: stratospheric nuclear tests of the 1950s and 1960s).