Mineral composition of drinking water and daily uptake

Conductivity gives a rough idea of the amount of dissolved ions in water (mS/m) or (µS/cm). Distilled water is <1 µS/cm, Reverse Osmosis treated 1-10 µS/cm, water from some sorts of sandstone or from granite (soft water) 5-15 µS/cm, and water from limestone (hard water) 20-200 µS/cm. Thus, the variation of the contribution of minerals from drinking water is large. A Swedish study on well waters, bottled waters and municipal waters showed the following contributions to the daily intake (2 L consumption): Ca 0-72%, Mg 0-69%, Na 0-65%, Cu 0-250%, Fe 0-46%, without considering that minerals in water generally are more readily absorbed in the intestines than minerals from food. Some springs and bottled waters with elevated concentrations of especially Ca, Mg and HCO3 may be regarded medical waters and used by people suffering from acidosis and subsequent diseases.