Traces of effects of acid rain, sedimentation, in the re-dissolution of cave dripstones
ENDINS, n.O 13. 1987. Ciutat de Mallorca.
TRACES OF EFFECTS OF AClD RAlN
(SEDIMENTATION) IN THE RE-DISSOLUTION OF
CAVE DRIPSTONES
by László JAKUCS (Hungary)
Resurn
Des del 1980 vaig cornencar a observar que certs espeleoternes (especialrnent estalagrnites) de
coves carstiques d'Hungria presentaven fenornens de redissolució, els quals no havien estat visibles
en aquestes coves 5-10 anys abans. Aquestes deforrnacions inqüestionablernent es deuen als efec-
tes corrosius de les aigües carstiques que alimenten els esrnentats espeleoternes. Arnb la intenció
de clarificar les causes d'aquest efecte, els rneus cornpanys i jo rnateix cornencarern les investiga-
cions no tan SOIS
a Hungria sinó tarnbé en coves de Txecoslovaquia, Rumania, Bulgaria, lugoslavia i
Austria. Fou possible establir que I'extensió del fenornen es universal a Europa Central, encara que
en diversos graus depenent de les particulars condicions naturals de cada cova.
Signes de la sindrome de degradació recent dels espeleoternes: craters irregulars de voreres
agudes i dentades; calderes arnb els costats soscavats; solcs de drenatge poc fondos, arnb voreres
tallants; redissolució superficial de I'espeleoterna en la zona d'esquits produits per degotarnents des
d'una certa altura; sovint, el subseQüent reblanirnent del material dels espeleotemes, que presen-
ten, aixi, un aspecte crernós.
Les investigacions que he realitzat fins ara indiquen que una gran gruixa de la coberta edafica
bioactiva i perrneable que reposa sobre la roca carstificable, aixi corn la rnajor profunditat de les
arrels de la rnacrovegetació (arbres de fulla caduca) desenvolupada sobre I'esrnentat sol, són res-
ponsables d'una gran incidencia i extensió d'aquest nou tipus de redissolució d'estalagrnites i espe-
leotemes en general. En base a les dades disponibles, pareix probable que els boscos de pins tin-
guin un paper una mica diferent en aquest aspecte, en cornparació arnb el paper desenvolupat pels
boscos d'arbres de fulla caduca, per exernple, roures, faigs, etc.
Es pot cornprovar un cert grau de proporcionalitat inversa entre la freqüencia de la sindrorne de
degradació dels espeleoternes i la profunditat de la cova en qüestió respecte de la superficie. A una
cova situada a rnenys profunditat arnb relació a la superficie, li correspon una presencia rnés proba-
ble d'aquest nou tipus de degradació d'espeleoternes.
Subsegüentrnent, vaig realitzar una serie d'analisis per establir de quina manera la sindrorne de
degradació observada es correlaciona arnb el pH del sol drstic i arnb els parametres rnicrobiologics
i de cornposició del sol. Foren documentades les tendencies en els canvis quirnics de les aigües
carstiques que penetren en les coves.
Es pot constatar que, en cornparació arnb les dades d'analisis d'aigües realitzats el 1929, els
quals foren ernprats corn a base de referencia, hi ha hagut un increment del 400-600 % en el contin-
gut de sulfats de les aigües carstiques que gotegen en identics punts de les coves; foren obsewats
tarnbé petits incrernents en els continguts de nitrats i clorurs. En aqueixes coves i, en particular, en
les zones on la redissolució dels espeleoternes era especialrnent intensa, el contingut de sulfats de
les aigües carstiques era mes alt que la rnitja.
Les rneves investigacions suggereixen, per tant, que aquesta degradado dels espeleotemes pot
ser induida pel recent i fort increment de la concentració de sulfats en les aigües carstiques, o indi-
rectament per qualsevol dels factors responsables de I'esmentat increment en el contingut de sulfats.
Sumrnary
Frorn 1980 on, I began to discover that certain dripstones (rnainly stalagrnites) in karstic cave
systerns in Hungary were exhibiting re-dissolution phenornena which had not been visible in the
caves 5-10 years previously. These deforrnations unquestionably arise frorn the corrosional effects
of karst-waters permeating onto the dripstones. With a view to clarifying the causes of this effect,
my colleagues and I comrnenced researches in situ not only in Hungary, but also in caves in Cze-
choslovakia, Rumania, Bulgaria, Yugoslavia and Austria. We established that the spreading of the
phenornenon is universal throughout Central Europe, though to different extent in caves with diffe-
rent natural features.
Signs of the recent dripstone degradation syndrome: sharp, jagged-edged, irregular-shaped cra-
ters; ((calderas)) with underrnined sides; sharp-edged, basin-like drainage trenches; areal dripstone

surface re-dissolution in the splash-spray zone of the water drops falling from the heights; in certain
cases alrnost total dripstone dissolution; ofien, the subsequent softening of the material of the
dripstones, which become crearn-like.
M y investigations to date indicate that, the thicker the bioactive and permeable soil layer cove-
ring the karst rock, and the deeper the roots of the rnacrovegetation (deciduous treesi growing in
this soil, the more frequent or the more extensive the new type of dripstone re-dissolution. On the
basis of the available data, it seerns probable that pine woods play a sornewhat different role in this
correlation systern frorn the role of deciduous woods, e.g. oak, beech, hornbearn, etc.
A certain degree of inverse proportionality can be documented between the frequency of occu-
rrence of the dripstone degradation syndrorne and the depth of the cave zone in question beneath
the surface. The srnaller the depth of a cave systern beneath the surface, the more likely the occu-
rrence of this new type of dripstone degradation in it.
I subsequently rnade a wide-ranging analysis of how the obsewed degradation syndrorne is co-
rrelated with the pH of the karst soil and with the rnicrobiological and soil-cornposition parameters.
The trends in the chemical changes of the karst-waters entering the caves were documented.
It turned out that, cornpared to the water analysis data frorn 1929, which were used as refe-
rente basis, there had been an increase of 400-600 % in the sulphate content of the karst-water
dripping in at the sarne points of the caves; srnaller increases were also obsewed in the nitrate and
chloride contents. In those caves and on those dripstones where the dripstone re-dissolution was
particularly extensive, the sulphate content of the karst-water was higher than average.
M y researches therefore suggested the result that the recent dripstone degradation rnay be in-
duced either by the recent strong increase in the sulphate concentration of the karst-waters, or indi-
rectly by one or other of the factors res~onsible
for the increase in the sulphate content.
In karst caves one can encounter extensive
signs of dripstone degradation processes induced
by some form of corrosion, ¡.e. the re-dissolution
of the material of the dripstone. There may natura-
Ily be numerous causes of corrosional dripstone
degradation, and the system of the mechanism of
action, involving the correlations between the in-
ducing factors and the resulting degradation symp-
toms, are fairly well known. A number of types of
corrosional dripstone degradation are known
which have age-independent genetics, ¡.e. which
may occur in al1 phases of the development of a
cave system; the system of conditions for their for-
mation were present in the distant past of the cave
(or in certain periods in the distant past) in the
same way as in the present day. Unfortunately,
however, the results of my researches indicate that
there are also certain corrosional processes which
are causing the degradation of cave dripstones
only in the present; prior to the period covering the
past 10-20 years, these processes have not been
manifested anywhere or at any time in cave for-
mations.
The first group, ¡.e. the group of corrosion va-
riants manifested independently of the age, include
co rrosion by unsaturated cave waters, mixing co-
rrosion, hurnidity condensation dripstone corro-
sion, the corrosion of cave soils and karst-water
clay, guano corrosion and the corrosion of dripsto-
Photo 1. A stalagmite that has been degrading seriously for se-
veral years in the charnber ~Magyarok-bejovetelen
in
nes of cave entrances. These are the traditional or
the Baradla Cave in Hungary. The recent corrosion by
permanent types of corrosional dripstone degra-
the continuously dripping karst-water has etched away
dation.
the outermost (youngest) dripstone layers.

These may be clearly distinguished frorn a cha-
racteristic group of syrnptoms of dripstone degra-
dation which were earlier never observed anywhere
in caves. The latter have appeared in the second
half of the twentieth century, and I have therefore
named this phenomenon the recent dripstone de-
gradation syndrome.
Frorn 1980 on, I began to discover that certain
dripstones (mainly stalagmites) in karstic cave sys-
tems in Hungary were exhibiting re-dissolution
phenomena which had not been visible in the ca-
ves 5-10 years previously. These deformations un-
questionably arise from the corrosional effects of
karst-waters permeating onto the dripstones. With
a view to clarifying the causes of this effect, my
colleagues and I commenced researches in situ not
only in Hungary, but also in caves in Czechoslova-
kia, Rumania, Bulgaria, Yugoslavia and Austria. We
established that the spreading of the phenornenon
is universal throughout Central Europe, though to
different extents in caves with different natural
features.
Signs of the recent dripstone
degradation syndrome
Sharp, jagged-edged, irregular-shaped craters;
(ccalderas)) with undermiiied sides; sharp-edged,
Photo 2. The altered character and effects of the water dripping
onto the dripstones are indicated by the sharp-edged
basin-like drainage trenches; areal dripstone sur-
corrosion pits at several sites on the sides of the sta-
face re-dissolution in the splash-spray zone of the
lagmites. The photo was taken in the «Meseország»
water drops falling from the heights; in certain ca-
section of the Aggtelek Cave in Hungary.
ses alrnost total dripstone dissolution; often, the
subsequent softening of the material of the drips-
years and very brief, ((post-soot)) active degrada-
tones, which become crearn-like (See Photos 1-3).
tion period lasting at most a few decades (but in
It must repeatedly be emphasized that the re-
m y view probably rather only a few years), which
cent dripstone degradation syndrorne I have inves-
has left active recorrosional (re-dissolution) traces
tigated and described involves damage to dripstones
on the surfaces of rnany cave dripstones, and which
that has occurred for at most few years (possibily
has even led in one or two cases to the total des-
around a decade). This darnage is observed virtua-
truction of the dripstone formation (see Photo 4).
Ily exclusively at those points in the dripstone ca-
ves that are subject to the most continuous drip-
ping; similar changes are never to be seen in or on
the long ago forrned layers or surfaces of the sarne
Research into the causes of the
formations. This correlation can be checked parti-
degradation syndrome
cularly easily in those caves which have long been
known and visited, and in which, in the period of
This recent dripstone re-dissolution is genera-
visits by torchlight (right up to the beginning of the
Ily displayed by the youngest dripstone forma-
twentieth century), a layer of soot of various thick-
tions, which are ;ti11 active as regards water-
nesses was deposited from the torch smoke onto
dripping, and which in the vast majority of the ca-
the dripstone and the rock surfaces. To outline the
ses are light in colour (frequently white). The phe-
essence: the dripstone degradation syndrome 1
nomenon is to be observed only in certain zones of
was studying is not present anywhere under the
the caves. The degradation usually exhibits group
soot layer. This rneans that in the course of deve-
occurrence, but stalagmites not showing signs of
lopment of these caves a clear distinction may be
re-dissolution may be encountered in the immedia-
made between a rrpre-soot)), symptom-free deve-
te vicinity of degrading dripstones. Research into
lopmental period lasting for man y thousands of
the causes of the symptorns is still continuing, but

Amateurska
JavoriEko Cave
Oemanova -Cave
Demanova -Cave
VazeC - Cave
Gombaszog -Cave
Katerinska
(N. Moravian Karstl
upper levels
lower levels
(Moravian Karst)
rnean depth o f cave
b e l o w surface
pine forest
$ $ 9
' * i o m p a c t deciduous woods
.U q w x rneadow, pasture
extent o f degradation of
n e w type (suibjectivei
Figure 1. Assurned correlation systern between depths of some
c z e c h o s l o v a k cave systerns below the s u r f a c e , the
type of surface vegetation, and the degree of present
dripstone degradation ( o r i g i n a l ) .
HUNGARY
YUGOSLAVIA
YUGOSLAVIA
YUGOSLAVIA
YUGOSLAVIA
AUSTRIA
CerovaEke - Cave
CerovaCke - Cave
Baradla -Cave
Ponojanska -Cave
Skocjanska - Cave
lower leve1
upper level
Eisriesenwelt
.Yu,,%,
karstic bush woods
2oo
6 4 4 pine forest
1 99
rnean depth of cave
2
deciduous woods
b e l o w surface
bare, cold karst
0
extent o f degradation of
free f r o m vegetation
n e w type (subjective)
and soil
Figure 2. Assurned correlation systern between depths of sorne
hungarian and foreign cave systerns below the sur-
face, the type of surface vegetation and the degree of
present dripstone degradation (original).

Photo 3. A stalagmite about 30 cm high in the Gombaszog Cave
Photo 4. In recent years the dripping karst-waters have in some
in Czechoslovakia. Within a few years, one side of the
places become strongly aggressive towards lime. They
previously intact, smooth-surfaced stalagmite has
no longer build up the stalagmites, but degrade them
been totally degraded by the phreatic water permea-
to their component layers. The dripstone has degraded
ting through the wood-covered soil.
to a loose structure, and the outer residues break away
from the disintegrating figure. The photo also reveals

how the rebounding karst-water spray is re-dissolving
the dripstone layers of the rock walls too (Gombaszog
it appears that sufficient data are already available
Cave, Czechoslovakia).
for some assumptions to be made concerning the
correlations. These are as follows:
1. In al1 cases, the re-dissolution of the drips-
and the deptli of the cave zone in question beneath
tone is caused by the same water-dripping as that
the surface. The smaller the depth of a cave sys-
which earlier caused the build-up of the dripstone
tem beneath the surface, the more likely the occu-
(primarily stalagmites are involved). The fact of de-
rrence of this new type of dripstone degradation in
gradation is therefore evidence that a change has
it.
occurred in the chemical or physicochemical pro-
The correlations referred to in points 2 and 3
perties of the water dripping onto the stalagmite.
are illustrated in Figs 1 and 2 on the example of
2. My investigations to date indicate that, the
some caves in Czechoslovakia, Hungary, Rumania
thicker the bioactive and permeable soil layer co-
and Austria.
vering the karst rock, and the deeper the roots of
I subsequently made a wide-ranging analysis
the macrovegetation (deciduous trees) growing in
of how the observed degradation syndrome is co-
this soil, the more frequent or the more extensive
rrelated with the pH of the karst soil and with the
the new type of dripstone re-dissolution. On the
microbiological and soil-composition parameters.
basis of the available data, i t seems probable that
The trends in the chemical changes of the karst-
pine woods play a somewhat different role in this
waters entering the caves were documented.
correlation system from the role of deciduous
It turned out that, compared to the water ana-
woods, e.g. oak, beech, hornbeam, etc.
lysis data from 1929, which were used as reference
3. A certain degree of inverse proportionality
basis, there had been an increase of 400-600 % in
can be documented between the frequency of oc-
the sulphate content of the karst-water dripping in
currence of the dripstone degradation syndrome
at the same points of the caves; smaller increases

were also observed in the nitrate and chloride con-
in the composition of the karst soils and in their
tents. In those caves and on those dripstones
microbiological conditions are correlated with the
where the dripstone re-dissolution was particularly
atmospheric acid sedirnentation. On this basis it
extensive, the sulphate content of the karst-water
appears to be proved that the rnodifications in the
was higher than average.
chemical characteristics of the karst-water are con-
My researches therefore suggested the result
nected with the trends in the physicochernical
that the recent dripstone degradation may be indu-
changes in the karst soil and with the present dis-
ced either by the recent strong increase in the sul-
tortions in the ecological conditions of the soil
phate concentration of the karst-waters, or indirectly
micro-organisms. The recent dripstone degrada-
by one or other of the factors responsible for the
tion syndrome therefore provides an overall indica-
increase in the sulphate content.
tion of the effects of acid rain or sediments in the
With the help of my colleague llona Bárány-Ke-
complex concatenation of correlations in the dee-
vei, I was similarly able to document how the trends
perkarst levels (see Tables 1-4 and Figs 3-5).
examination
PH
7.1
7.3
6.6
7.2
7.0
7.2
7.1
7.0
6.9
6.91 7.5
7.2
7.0
6.9
Ca++ mgll
103.0 124.0 86.0 92.0 83.0 101.0 122.0 99.0 92.2 98.6
54.2 106.0 111.0 83.8
Mg++ mg/l
1.0
2.2
1.4
4.5
2.2
1.9
1.9
3.7 12.2 11.3
3.2
2.1
3.1
3.3
HC0,- mgll
298.0 370.0 281.0 322.0 267.0 288.0 380.0 235.0 238.0 226.0 174.0 303.0 310.0 266.0
SO,-- rngll
14.0
9.2 47.0
8.5 33.4 12.2 17.0 27.7 307.0 250.0 16.1
8.9 24.1
29.9
CI- rngll
3.0
3.6
8.2
4.1
6.8
2.3
2.1
16.1
11.0 11.0
3.6
5.0
14.3
6.5
NO,- rngll
16.2 14.8 43.2 13.7 40.9 12.2 14.2
9.7
5.9
2.2
1.0
4.2 20.3
23.5
1, 2, 3 = Baradla - Cave, Lace Well (Jakucs)
4, 5 = Baradla - Cave, Chinese Pagoda (Jakucs)
6, 7, 8 = Béke - Cave, Arnphora (Jakucs)
9 = Létrási -vizes - Cave, Point 4. (Lénárt)
10 = Létrási - vizes - Cave, Point 7 (Lénárt)
1 1 = Baradla - Cave, Dessewfiy Well (Maucha)
12, 13 = Postojanska - Cave, Calvary (Jakucs)
14 = Dornica- Cave, Hall of lndian Pagodas (Jakucs)
Table 1. Cornparative chemical analyses of various cave dripwaters at different and identical times





1
2
3
4
6
19.83
19.07
24.68
23.58
23.51
2.37
3.34
0.97
1.03
0.69
6.95
9.3
2.55
9.66
22.29
66.80
69.88
69.26
71.38
53.16
72.82
^I
1 = 30.07.1929 (dota of Maucha)
C_L_LLe Ca'.
2 = 30.03.1984 (data of Csernavolgyi - Major)
ó á
3 = 15.03.1985 (original)
Mg*
E
4 = 26.04.1985 (original)
5 = 20.08.1985 (origina l)
6 = 27.10.1985 (original)
HCOr
v o
SOa -
Figure 3. Water of okirálykúto dripstone basin (Baradla - Cave at
Aggtelek)
30.07.1929.
30.03.1984.
15.03.1985.
21.03.1985.
26.04.1985.
20.08.1985.
27.10.1985.
mg/I
(Maucha)
(Csernavólgyi-
(Jakucs-
(Jakab-
(Jakucs-
(Jakucs-
Jakucs-
REFERENCE
Major)
Franczia)
Major)
Franczia)
Franczia)
Franczia)
++
Ca
93.4
63.4
87.0
64.3
114.4
98.2
88.6
Mg ++
2.7
2.6
1.7
12.7
0.5
3.3
2.4
HCO3 -
282.4.
.
143.0
331.0
267.3
325.0
246.0
321.7
SO4--
9.9
59.9
44.0
46.9
47.0
34.4
43.2
NO3-
12.3
- ?
20.2
- ?
11.4
17.9
8.2
Cl -
2.7
25.4
7.1
1.8
14.4
21.0
5.8
Tabla 2. Analyticall data on ions expressing the trends to change in the water composition of the "Királykút" dripstone basin in the Baradla cave
55

1 = 29.10.1929 ievels (data of Mauchal
2 = 15.03.1985 (original)
3
= 26.04.1985 (original)
4 = 20.08.1985 (original)
5 = 27.10.1985 (original)
Figure 4. Water of vkéregeto - koldusn stalagmite (Baradla -
Cave at Aggtelek)
1 = Amateurska - Cave, Moravian Karst, 05.06.1965 (original)
2 = JavoriCko - Cave l., N. Moravian Karst, 06.06.1985 (original)
3
= JavoriCko -Cave II., N. Moravian Karst, 06.06.1985 (original)
4
= Deminova - Cave, Low Tatra, 06.07.1985 (original)
5 = Vazetka -Cave, High Tatra, 06.08.1985 (original)
Figure 5. Waters of degrading stalagmites (Czechoslovak caves)

29.1 0.1 929.
15.03.1 985.
26.04.1 985.
20.08.1 985.
27.10.1985.
mg/l
(Maucha)
(Jakucs-Franczia)
(Jakucs-Franczia)
(Jakucs-Franczia)
(Jakucs)
REFERENCE
Ca+
66.7
96.0
130.8
104.2
98.7
+
Mg++
2.0
1.5
1.7
20.2 (?)
1.4
HC03-
204.0
41 5.0
406.0
41 0.0
392.8
SO4--
12.4
42.0
43.2
28.6
45.3
NO3-
8.5
14.2
1.8
17.5
8.2
CI-
1.5
7.8
6.8
9.3
4.5
Table 3. Analytical data on ions expressing the trends to change in the water composition of the "Kéregeto-koldus" stalagmite
in the Baradla cave
AMATEURSKA-
JAVORICKO-
JAVORICKO-
DEMANOVA-
VAZECKA-
mg/l
CAVE
CAVE l.
CAVE II.
CAVE
CAVE
05.06.1 985.
06.06.1 985.
06.06.1 985.
07.06.1 985.
08.06.1 985
Caf + Mg++
80.1
95.8
70.5
30.8
57.2
+
HC03-
372.0
421 .O
249.0
237.0
300.0
SO4--
73.0
99.0
94.0
26.0
23.0
NO3-
4.77
11 .O
15.0
6.03
1.8
CI-
10.65
8.88
8.88
3.55
5.33
Table 4. Analytical data on karst waters collected from dripstone formations attacked by recent corrosion in some czechoslovak caves