Table 1.

Chemical characteristics of tap and natural mineral waters.

Characteristics	Tap water	Hypersaline sodium-rich naturally sparkling mineral water—Pedras Salgadas
Total mineralization (mg/L)	148–151	2855
pH	6.5–9.0	6.16
Sodium (mg/L)	200	591
Calcium (mg/L)	30.5–40.2	92.5
Magnesium (mg/L)	3.6–9.2	26.2
Potassium (mg/L)	2.6	29.9
Copper (mg/L)	2	0.0013
Zinc (µg/L)	∗	1.1
Selenium (µg/L)	10	<2.0
Bicarbonate (mg/L)	∗	2013
Chloride (mg/L)	250	30.8
Sulphate (mg/L)	250	6.4

∗: no need for control (Portuguese Act 306/2007, from 27th of August).