Thermal waters: classification based on the saline concentration

A first classification of thermal waters takes place on the basis of the concentration of certain minerals. The latter is expressed in mg/l and takes the name of fixed residue , defined as the solid substance remaining after having evaporated a quantity of filtered water. We therefore speak of waters:

• Slightly mineralized : the fixed residue is less than 80 mg/l ;
• Oligominerals : the fixed residue is between 80 mg/l and 200 mg/l ;
• Mediominerals : the fixed residue is between 200 mg/l and 1 g/l;
• Minerals : the fixed residue is between 1 g/l and 30 g/l;
• Salted : the fixed residue is higher than 30 g/l;

Thermal waters: classification based on the saline composition

Thermal waters are also divided according to the content of certain chemical elements. The classification is as follows:

• Sulphurous waters: this is the most common type of thermal water in our country. Among the spa resorts where sulphurous waters abound, we mention Saturnia, Sirmione, Tabiano, Bagno di Romagna, Riolo Terme and Acqui Terme. They are waters rich in sulfur (S), a chemical element belonging to non-metals which is present in a bivalent form  and gives them their characteristic penetrating smell. They are indicated for the treatment of bone disorders, respiratory disorders and skin disorders. The sulfur is inhaled or absorbed by the skin through contact with the mud;
• Sulphate waters : unlike sulphurous waters, sulfur is present in the hexavalent form in sulphate waters . Thanks to their laxative effect, these waters are recommended for disorders of the digestive and gastrointestinal systems, as well as those of the liver. Among the localities that host sulphate water springs are San Pellegrino Terme, Boario and Chianciano Terme. It is possible to take sulfur by applying the mud of the waters to the skin or by drinking it directly.
• Chloride-sodium waters : they are characterized by the presence of chlorine (Cl) and sodium (Na), elements that make them suitable for the treatment of rheumatic disorders, bone disorders and cardiovascular system disorders. In Montecatini Terme and on the island of Ischia there are some of the most famous sources of sodium-chloride waters. The treatment usually involves inhalation, but it is also possible to drink them or apply the mud to the skin;
• Salty-Bromo-Iodine waters : they are rich in sodium chloride (NaCl), bromine (Br) and Iodine (I). In Italy the most renowned places for thermal springs of this type are Salsomaggiore Terme, Sirmione, Bacoli and Sassuolo. They are characterized by the typical saline taste of the waters and are recommended for their anti-inflammatory and antimicrobial action on the female reproductive system, but they are also used in treatments against osteoarticular disorders. They can be drunk, inhaled or come into contact with the skin through the sludge;
• Bicarbonate waters : as the name suggests, magnesium carbonates (MgCO₃) and calcium carbonates (CaCO ₃ ) abound in these waters . There are numerous brands of bicarbonate water on the market, which can therefore also be drunk at home.
• Radioactive waters: these are waters that contain certain quantities of natural elements with radioactive properties such  as radium (Ra), actinium (Ac), uranium (U) and radon (Rn). If dangerous at high concentrations, at low concentrations these substances seem to stimulate the activation of the immune system, act on the nervous system as sedatives and analgesics, and be useful in the treatment of gout and hyperuricemia. There are spas with radioactive water in Ischia, Bormio, Merano, Lurisia, Latronico, Abano Terme and Montegrotto.

Thermal waters: classification based on temperature

Thirdly, thermal spring waters can also be classified according to their temperature. In this case, therefore, we are talking about water:

• Cold : the temperature is lower than 20°C ;
• Hypothermal : the temperature is between 20°C and 30°C ;
• Thermal or Homeothermal : the temperature is between 30°C and 40°C ;
• Hyperthermal : the temperature is higher than 40°C ;

The benefits of thermal waters on human health

Thermal waters can bring enormous benefits to human health due to the substances contained in them.

Inhalation treatments with thermal water are often prescribed to those suffering from respiratory system disorders. Simple inhalation is recommended against chronic rhinosinusitis-bronchial syndromes, chronic laryngopharyngitis, chronic sinusitis, while for subjects affected by simple chronic or chronic obstructive bronchitis, the combination of inhalation treatments and pulmonary ventilation is often opted for . Inhalation treatments can also be used in combination with other treatments for hearing disorders, such as chronic catarrhal otitis or chronic purulent otitis ( source ).

Mud-based therapy (or balneo -mud therapy ) is instead recommended for osteoarthritis and rheumatic diseases, while ablutions in thermal water (or balneotherapy ) serve to mitigate skin diseases such as seborrheic dermatitis , atopic dermatitis , eczema and psoriasis.

Against gynecological disorders such as non-specific vaginitis, dystrophic vaginitis or recurrent leucorrhoea, vaginal baths and irrigations are prescribed in thermal springs with salty-bromine-iodine waters .

The hydromassage with thermal water helps to mitigate the symptoms of various types of chronic phlebopathies, i.e. pathologies affecting the veins located in the lower limbs. Finally, taking some types of thermal water orally ( mineral water treatment ) is recommended against gastrointestinal disorders such as constipation, dyspepsia (difficulty digesting food) or irritable bowel syndrome.