Vol.2, No.11, 1260-1263 (2010)
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
Problems with classification of spa waters used in
Csaba Varga
Department of Environmental Health, University of Pécs, Pécs, Hungary; chemsafety@freemail.hu.
Received 14 September 2010; revised 25 September 2010; accepted 30 September 2010.
Recently, several measurements have indicated
the presence of biologically active organic mi-
cropollutants or trace components in different
types of waters, including spa and medicinal
waters. The wide spectrum and abundance of
organic components of spa waters in the Car-
pathian basin and other European regions has
been demonstrated by gas-chromatographic ana-
lyses. These components may have main role in
the therapeutic and preventive mechanisms.
Considering the new analytical data, traditional
European classification of spa waters based on
the quality and quantity of inorganic ions (salts)
should be reevaluated. The association of inor-
ganic components and the therapeutic effects is
also necessary to reconsider.
Keywords: Spa Water; Medicinal Water;
Classification; Organic Compounds; Balneotherapy;
Therapeutic use of spa (thermal) waters has been a
part of the cultural and medical traditions of the Euro-
pean and especially the Central European (CE) nations.
Frequent visits of middle-class people and the aristoc-
racy at the famous spas were social events, as well. That
is why successor countries of the former German Empire,
Italy and Austro-Hungarian Monarchy have preserved
this unique culture and their scientists are overrepresented
in balneological science and mineral water chemistry,
even today.
In spite of the expansive research, we are not aware of
the exact mode of action of the different spa waters. Only
few countries have specific regulations or acts in this
field. Based upon the regulations of CE countries (e.g.
Hungary, Slovakia, and Romania) a simple analytical
study is enough for qualification as “mineral water” [1-
3]. However, medical observation is also needed for qua-
lification as “medicinal water”, that is, a specific thera-
peutic effect should be proved in a comparative study, by
using treated and placebo groups of patients [3-5]. Its
exact way is to perform a double or triple blind (inter-
ventional) epidemiological study [6-8]. In brief: the law
in the CE countries declares that medicinal waters should
be mineral waters, but mineral waters are not definitely
medicinal ones.
The effects of spa waters were already well-known in
the 16th century [9]. At the turn of the 20th century, a
series of scientific books mapped the most important
spas in the Carpathian Basin (Hungarian Kingdom) from
the Highland (recently Slovakia) to Transylvania (recently
Romania) from point of view of geology, chemistry and
therapeutic effects [10,11]. The inorganic analysis of wa-
ters has been performed accurately since the 18th-19th
centuries, therefore their medical effects have also been
tried to explain with the salt content. Traditionally, me-
dicinal (or healing) waters in the European literature are
categorized into the following groups [12,13] indicated
in Table 1.
The healing effects of balneotherapy in wide range of
diseases are well described [14], however, exact mecha-
nism of the healing spa cure is completely unknown, at
least its relationship to the presence of certain chemical
ingredients. The well-known physical (thermal, mecha-
nical) features affect the circulation and locomotor or-
gans (disorders). But same effects can also be detected
using simple hot water as a consequence of the similar
hydrostatic and thermal circumstances.
The chemical effects may be caused by the substances
forming real aqueous solutions or colloidal systems.
Their absorption takes place through the skin, or in case
of volatiles, by inhalation. The classical theory tries to
explain the therapeutic efficiency exclusively with the
presence of inorganic ions (salts) and gases. That is why
C. Varga / HEALTH 2 (2010) 1260-1263
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Table 1. Classification of medicinal waters (modified Papp’s
Category Main features
Simple thermal waters 25
Simple acidic (carbonized)
waters 1 g/L free CO2
Alkaline (Na-K-bicarbonated)
1 g/L total dissolved solid,
dominant anion: HCO3-
Ca-Mg-bicarbonated waters
1 g/L total dissolved solid,
dominant cations: Ca2+, Mg2+
dominant anion: HCO3-
Chloridated (saline) waters
1 g/L total dissolved solid,
dominant cation: Na+
dominant anion: Cl-
Ironic (ferrous) waters 10 mg/L Fe2+ or Fe3+
Sulphuric waters Total sulphur 1mg/L (HS- or
S2O32- or S2- or H2S)
Sulphated waters 1 g/L total dissolved solid,
dominant anion: SO42-
Iodated-bromidated waters 1 mg/L I- or 5 mg/L Br-
Radioactive waters Radon or toron content
the presently used classification of spa waters are based
on the inorganic contents.
The basic problem of balneology (balneotherapy, bal-
neoprevention) can be outlined with a simple formal lo-
gical approach. If A contains B too (that is the spa water
contains salts too) and A cures C (that is water is effec-
tive in some diseases), it does not mean that B cures C.
Therefore not definitely the salts which are effective in
the water, since other components are (may be) also pre-
sent in it, not just salts. In this study we try to collect the
direct and indirect evidences for an unconventional ex-
planation on the mode of action of spa waters used in pre-
vention and therapy.
3.1. Why Medical Trial is Necessary for
Qualification of Spa Water as
“Medicinal Water”?
Because, the exact inorganic analytical study cannot
predict the therapeutic efficiency. We have no exact data
whether redissolution of the total salt content in distilled
water can recover the therapeutic effects. Sometimes, even
the complete redissolution of salts is impossible without
3.2. All Known Medicinal Water Contain
Organic Fraction
Results of science and practice of organic water analy-
tics cannot be neglected by balneology, either. Recently,
several measurements have indicated the presence of bio-
logically active organic micropollutants or trace compo-
nents in different types of waters, especially in disin-
fected drinking waters [15,16]. Observed concentrations
are very low: pg/L, ng/L or μg/L, but biologically active
compounds may have stochastic effects without thresh-
old dose. The wide range of organic components of spa
waters in the Carpathian Basin [17] and other European
regions [18,19] is also demonstrated by the state-of-art
analytical methods. Hot spring or deep artesian well wa-
ters may contain many identified and unidentified com-
pounds from the simple aliphatic through the simple aro-
matic hydrocarbons to the heteroaromatics and sophisti-
cated polycyclic aromatic compounds. A simple gas-chro-
matogram can characterize the unique spa water or its
springs and wells, like a fingerprint [20-22] (Figure 1).
These components either may have main role in the
therapeutic mechanism or/and probable toxicity [23].
3.3. Biological Activities
Even biological activities of the single aquatic organic
compounds are not known, but we are not aware of their
possible interactions, in particular. At least one biologi-
cally active organic compound has, however, been well-
known for a long while. Water and mud of some Hun-
Figure 1. Gas-chromatogram of a drinking water sample (up)
and a Hungarian medicinal water sample (Hajdúszoboszló)
(down). (Etanol extraction, temperature programming, FID).
C. Varga / HEALTH 2 (2010) 1260-1263
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Openly accessible at
garian spas contain natural estrogens of geochemical ori-
gin and are highly effective in gynecological postopera-
tive states and disorders [12]. In this case, salt quality and
concentration is probably indifferent.
3.4. Dissolution and Absorption
Organic fraction can also promote dissolution of inor-
ganic compounds and their absorption into the human
body. Therefore, modeling of absorption using inorganic
isotopes alone is not valid if the organic complexes pro-
mote this process.
3.5. Blood Analyses
Chemical analysis of patients’ blood samples for the 4
main cations could not show any evidence of absorption
during bathing in spa waters. A Hungarian study suggests
that the main inorganic cations (Na+, K+, Ca2+, Mg2+)
cannot have any effect, if they are absorbed at all, be-
cause their concentrations in the human body is higher
with several order of magnitude [24].
3.6. Mode of Action
Organic fractions of medicinal waters may have cru-
cial issue in the mode of action. Considering the new ana-
lytical data, traditional classification of spa waters based
upon the quality and quantity of inorganic ions (salts)
should be revaluated. The relationship of inorganic com-
ponents and the therapeutic effects is also necessary to
reconsider, excepting some specific waters used in drink-
ing cures (sulphated, alkaline, fluoridated, iodated waters).
3.7. Importance of Inorganic Analyses
The presence of the inorganic components and not least
the pH, however, can strongly affect the hydrophilic and
hydrophobic characteristics of organics, inhibiting or pro-
moting the absorption. Therefore inorganic analyses are
also crucial in assessment of the possible effects.
Spa (medicinal) waters should be reclassified in the
scientific literature related to their therapeutic and pre-
ventive characteristics. The new categories should also
be based upon the state-of-art methodological armament
of water analytics and therapeutic evidences, meeting
requirements of the 21st century. At present, we have li-
mited data to establish such a new system due to the lack
of organic analyses. Complete set of data needs to be re-
gistered in case of medicinal waters, involving determi-
nation of all chemical (inorganic and organic), geo-phy-
sical, hydrobiological, microbiological and toxicological
parameters, representing the particular medicinal water.
Quality assurance of therapeutic elements should also be
in close correlation with the parameters mentioned above.
On the other hand, a new logical possibility should be
ruled. Namely, if the therapeutic efficiency of particular
water is caused by organic compound(s), mineral content
as a necessary condition is not a valid parameter for
“medicinal water” qualification [25,26]. The chance for
the absence of the necessary salt concentration—re-
quired by the acts—in medicinal waters is actually very
little, but cannot be excluded theoretically. This logical
conclusion should be accepted by the regulatory authori-
ties, as well.
This work was supported by the Faculty of Medicine, University of
Pécs (grant No. 34039).
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