BIOINDICATION – IMPORTANT INSTRUMENT
FOR UNDERSTANDING OF POLLUTION LOAD IN FORESTS CLOSE
TO NATURE
Blanka MAŇKOVSKÁ
Forest Research Institute Zvolen, Masarykova 22, SK – 960 92 Zvolen, SLOVAK REPUBLIK, mankovska@fris.sk
Abstract
MAŇKOVSKÁ, B.: Bioindication – important instrument for understanding of pollution load in forests close to
nature.
The mosses Pleurozium schreberi and Hylocomium splendens were used as biomonitors to study the
atmospheric deposition of heavy metals over the territory of Slovakia. The samples of mosses were collected
in 86 permanent sites in accordance of the pan–European network (1616 km). The collection of moss was
performed during the first half of August 2000. A total of 44 elements were determined, including most of
heavy metals using instrumental neutron activation analysis (INAA) at the reactor IBR–2 in Dubna and
atomic absorption spectrometry VARIAN SPECTRA A–300 and mercury analyser AMA–254) in Zvolen.
Comparison with the limit values from Norway considered the pristine area shows strong pollution of the
examined areas of Slovakia with most of the heavy metals. The maximum level of pollution by heavy metals
was observed in the region Central Spiš. In comparison with the 1991 survey, the median values in 2000 for
Cd, Cu and Pb are ~50 % lower and for Zn even ~70 %. Fe and Hg showed practically no change. During the
same period concentration of such elements as Ni and V increased by ~50 %. This reflects falling–off the
production of steel and non–ferrous metals in Slovakia and decrease in using leaded gasoline. The main
source of increase of nickel and vanadium in air is gradually growing combustion of heavy oil and products
of its refining.
Key words: Biomonitors, Mosses, Lime wood, Atmospheric Deposition, Heavy Metals.
Introduction
The control of the atmospheric air quality is one of the most important tasks of the environmental
protecting program. Atmospheric air is one of the basic components of the human environment.
Cleanness of the air reservoir is a basic factor for the ecological balance and human health.
Between many pollutants heavy metals are the most toxic component for all living organisms.
Heavy metals are present in the atmosphere in organic and also in inorganic forms, in the form of dust
and aerosols. They can be transported to large distances from the source and where they fall out they
have a very negative impact on the environment.
Systematically surveys of the atmospheric deposition of heavy metals are performed in several
European countries every 5 years by means of the bio monitoring technique (Rűhling et al., 1998). It is
well established that the terrestrial mosses are among the most effective types of organisms for bio
monitoring due to a number of their biological features, widespread occurrence, and tendency to
accumulate and retain pollutants.
The last decade in the Slovak Republic extensive studies in this direction have been done during by
B. Mankovska. For analysis of environmental samples sophisticated equipment for atomic absorption
spectrometry (AAS) are used. Activities of the laboratory include multielemental analysis of soils, plants,
mosses, tree bark, humus and other environmental matrices Isoline maps of atmospheric deposition of
1
metals including the Slovak Republic territory were presented in a report issued by the Nordic Council of
Ministers (Rühling et al. 1998) and in the Geochemical atlas of Slovakia (Maňkovská, 1996).
Materials and methods
The samples of mosses were collected on 86 permanent plots situated in Slovakia at the intersections
of 16x16 km pan–European network. Moss samples (Pleurozium schreberi and Hylocomium splendes)
were collected according to the procedures used in deposition surveys in the Scandinavian countries.
The collection of samples was performed during the first half of August 2000 and was executed by a
specialist of the Forest Research Institute in Zvolen. The samples were subjected to analysis without
preceding washing, after drying at a temperature not exceeding 60 C for 24 hours.
The samples consisted of the last three years’ annual segments and represented the deposition of
heavy metals for the years 1998, 1999 and 2000. The concentration of Pb, Cd and Cu was determined
(with a precision of ~ 5%) in the Forest Research Institute, Zvolen, by flame atomic absorption
spectrometry with VARIAN SPECTRA A–300 and Hg by the mercury analyser AMA–254
manufactured by ALTEC, Prague. Elementary analyser LECO SC 132 was used for the determination
of the total concentration of sulphur in the mosses. The sample was weighed into a ceramic vessel and
burnt in oxygen atmosphere in induction furnace at the temperature 1371 C. Sulphur concentration
(as SO2) in gas was measured by infrared detector and compared with standard samples. The other 39
elements were determined by neutron activation analysis at the reactor IBR–2 (FLNP JINR Dubna,
Russia), which is equipped the fast pneumatic transfer system REGATA (Peresedov et al., 1996).
Moss samples of about 0.3 g were packed in aluminium cups for long–term irradiation or heat–
sealed in polyethylene foil bags for short–term irradiation in the IBR–2 reactor, Dubna, Russia. The
irradiation facilities used are briefly described in (Frontasyeva, Pavlov, 2000).
Elements yielding long–lived isotopes, 29 in all, were determined using the Cd–screened channel
1 (Ch1) (epithermal neutron activation analysis, ENAA). Samples were irradiated for 5 days, re–
packed, and then measured twice after 4–5 and 20 days of decay, respectively. Measurement time
varied from 1 to 5 hours. To determine the short–lived isotopes of Na, Mg, Al, Cl, K, Ca, Mn, Cu
(66Cu) I, and Br (80Br), channel 2 (Ch2) was used (conventional NAA). Samples were irradiated for 5
min and measured twice after 3–5 min of decay for 5–8 and 20 min, respectively.
Concentrations of elements yielding long–lived isotopes were also determined using certified
reference materials: SDM sediment (International Atomic Energy Agency, Vienna), Montana Soil
(NIST) and moss DK–1, prepared for calibration of laboratories participating in the corresponding
1990 survey in Northern Europe.
The induced activity can be measured using –spectrometers with Ge(Li) and HPGe detectors and
ORTEC electronics. The software developed at FLNP JINR is used for data processing (Ostrovnaya
et. al., 1993). The mentioned method can determine up to 45 elements. The concentration of elements
was determined with a precision of 8% – 18% (depending on the element), only for Br it was as high
as 25%.
It should be added that the INAA technique does not require sample dissolution, and therefore has
a great advantage if the total concentration is the aim of the analysis. Not all the above trace elements
are strictly relevant as air pollutants, but they come additionally from the multielement analyses with
insignificant extra cost, and most of them can be used as air mass tracers. Previous experience in
analysing environmental samples at JINR allows use of the epithermal neutron activation to determine
a considerable number of rare–earth elements as tracers of geochemical processes.
2
Results
The total concentrations of 44 individual elements were determined in 86 samples of mosses. The
mean, median, standard deviation and range values was determined (Tab. 1) for each elements. To the
best of our knowledge, such a large association of elements has never been studied before in
environmental samples from Slovakia.
Table 1. Concentration of elements (mg/kg) in mosses “Slovakia–2000”
Element
x
STD
Median
xmin
xmax
Ag
0.1
0.1
0.12
0.04
0.65
Al
3848
3408
2470
751
As
0.8
0.4
0.71
Au
0.0
0.0
Ba
61
Br
Element
x
STD
Median
xmin
xmax
Mn
437
291
350
64
1510
17400
Mo
1.1
0.6
0.91
0.20
2.87
0.34
2.21
Na
514
449
361
131
2423
0.002
0.00
0.015
Ni
3.9
2.9
3.2
0.7
12.6
45
51
11.9
343
Pb
32.8
21
28
9.7
109
3.7
1.3
3.5
1.38
6.6
Rb
16.9
10.2
13.4
4.8
53
Ca
5308
2673
4925
2080
16400
S
2013
191
2030
1190
3280
Ce
3.9
4.0
2.5
0.62
23
Sb
1.5
2.3
0.87
0.23
14.3
Cd
0.6
0.3
0.59
0.11
1.49
Sc
0.6
0.6
0.38
0.1
3.6
Cl
281
138
249
89
754
Se
0.4
0.2
0.33
0.14
1.13
Co
1.5
1.5
0.85
0.31
8.16
Sm
0.4
0.4
0.24
0.06
1.9
Cr
8.7
7.2
6.5
1.1
43
Sr
86
69
62
7.9
328
Cs
0.5
0.6
0.41
0.14
5.44
Ta
0.1
0.1
0.06
0,02
0.50
Cu
9.8
4.6
8.8
3.9
37
Tb
0.1
0.1
0.045
0.01
0.47
Fe
2211
2089
1561
430
13750
Th
0.5
0.5
0.31
0.10
3.2
Hf
0.7
0.7
0.39
0.10
3.95
Ti
57
53.4
35
10.2
304
Hg
0.4
0.7
0.18
0.06
3.44
U
0.1
0.1
0.10
0.03
0.66
I
2.0
1.2
1.72
0.76
8.00
V
7.4
5.6
5.7
1.8
30
In
0.2
0.2
0.11
0.01
1.60
W
0.3
0.2
0.25
0.06
0.70
K
7075
1971
6989
3464
15440
Yb
0.3
0.3
0.16
0.02
1.36
La
2.5
2.5
1.54
0.41
14
Zn
57
25
50
22
159
Mg
1734
1105
1395
414
92
102
54
14.7
512
6000 Zr
Note: x– arithmetical mean; STD –standard deviation; xmin –minimal value; xmax– maximal value
In order to better distinguish between contribution from air pollution and from a crustal component
associated with windblown soil particles (Rahn, 1976, 1999) enrichment factors (EF =
(X/Sc)moss/(X/Sc)soil) were calculated from the moss data and plotted in Fig. 1. Typical crustal elements
such as Al, Sc, REE, Th, U, etc. show EF values near unity (colorless symbol), whereas values
appreciably above that level indicate that the element in question is either enriched in the moss by
active biological processes (K, Ca) or in stems from atmospheric deposition. The elements Ag, As, Br,
3
1000
EF=(x/Sc)moss/(x/Sc)crust
S
Se
Ag
100
Cl
K
Cu
Ca
Hg
Sb
I
Pb
Zn
Br
Mn
10
Cd
Mo
As
Cr
Au
In
Zr
Cs
Sr
Hf
W
Co S, Ni
Cd, Cu, Cl,
Hg, In, Mn, Mo, Pb,
Sb, Se, and
are significantly
Rb Zn (marked black symbol),
Mg
Tb
U
Ce
V
Ba
enriched in the moss, clearly indicating that these elements represent a regional pollution problem.
1
Clearly the
moss is Sc
a far better Fe
medium to express regional contamination Yb
from atmospheric
Al
Sm
Th
deposition than the surface soil, as also concluded in a recent study byLaFernandez and Carballeira
Ta
(2001).
Na
Ti
0,1
Fig. 1. Enrichment factor of elements in Slovakia mosses with respect to crust.
The median values of concentration (mg/kg) heavy metals in Slovakia for V, Cr, Ni, Cu, Zn, Pb,
Cd and As, are compared (Tab. 2) with relevant data from similar areas of Europe: South Ural
Mountans (Frontasyeva et al., 2002), Poland (Rühling et al., 1998), Poland – Copper Basin
(Grodzinska et. al.), Tula (Ermakova et al. 2002) and the median value in Norway 2000 (Steinnes et al.
2001).
Comparison with the current median level in Norway shows strong pollution of the examined areas
of Slovakia with the most of heavy metals. Strongly elevated Pb values with compare even South Ural
Mountans is evident. The Cd value is 1.5 to 9 times higher than in other Europens regions, only
concentration of Zn are aproximetly equelly.
Table. 2. The median values of heavy metals concentration in mosses (mg/kg) collected from different
areas of Europe
Element
Slovakia
Ural
Tula
Norway
Years
2000
2000
2000
2000
1995
Copper basin 2000
V
5.6
9.4
5.7
1.3
3.9
2.,5
Cr
6.5
9.5
3.7
0.69
1.5
1.43
Fe
1560
1511
1660
362
362
357
Ni
3.2
6.2
3.2
1.1
1.44
1.83
Cu
8,7
13,5
8
4,2
7,6
20
Zn
50
49
52
32
43
45
As
0.71
1.45
0.4
0.135
0.44
0.61
Cd
0.6
0.3
0.28
0.087
1.5
–
Pb
28.0
7.4
8.2
–
13.6
–
Poland
4
Table 3. Concentrations of heavy metals in mosses collected in 1991, 1995, and 2000
Median [mg/kg]
Year
V
Cr
Fe
Ni
Cu
Zn
Cd
Hg
Pb
1991
–
3,4
1571
1,7
19
162
1,35
–––
41
1995
1,2
13,2
1483
2,0
16
49
1,2
0,11
23
2000
5,6
6,5
1560
3,2
8,7
50
0,6
0,18
28
In Slovakia mosses were sampled in their natural habitats in 58 localities in 1991, 78 in 1995
(Maňkovská, 1997) and 86 localities in 2000. In comparison with the 1991 survey the median values
in 2000 for Cd, Cu and Pb were reduced by approximately 50 % and for Zn even ~70 %. During the
same period elements such as Ni and V increased by approximately 50 %. Fe and Hg showed
practically no change. (Fig. 2.) Decreasing concentrations are connected with decreasing production of
steel and non–ferrous metals in Slovakia and with facing out leaded gasoline. The main source of
increase of nickel and vanadium in air is gradually growing heavy oil combustion. Maps of localities
is in Fig. 1; distribution maps of element concentration As and Hg in Slovakia are in Fig. 4.
100
Zn
100
Cu
10
Pb
1
Concentration (mg/kg)
Concentration (mg/kg)
1000
V
10
Ni
1
Cr
0,1
Hg
Cd
0,1
0,01
1991
1995
2000
1991
1995
2000
Fig. 2. Temporal changes of content of heavy metals in Slovakia mosses.
Banská Bystrica
Košice
Bratislava
Km
North
50.00
Fig. 3. Map of localities (16x16 km).
5
As
(mg/kg
%)
<0.6
0.6 - 1.0
1.0 - 1.5
1.5 - 2.0
>2.0
14.0
72.4
10.7
2.8
0.1
Banská Bystrica
Košice
Bratislava
Km
North
50.00
Hg
(mg/kg
<0.6
0.6 - 1.2
1.2 - 1.8
1.8 - 2.4
>2.4
%)
86.5
5.7
3.7
2.8
1.4
Banská Bystrica
Košice
Bratislava
North
Km
50.00
Fig. 4. Distribution maps of element concentration As and Hg in Slovakia.
Conclusion
Collected samples contained 3–year–old segments of mosses and it represented a deposition of
heavy metals for the years 1998, 1999 and 2000. During this period 47 t of arsenic, 11 t of cadmium, 9
t of chromium, 64 t of copper, 3,4 t of mercury, 35 t of nickel, 84 t of lead and 73 t of zinc were
emitted annually in Slovakia (Burda et al. 1999). The region near the border between Slovakia, Poland
and the Czech Republic is considered as the second ”black triangle” of Central Europe with
substantially higher concentrations of heavy metals than the first ”black triangle” near the borders of
the Czech Republic, Poland and Germany. Information about the air pollution status in different parts
of the Slovakia is essential for a better understanding of environmental stresses. Biomonitoring
6
techniques allow monitoring of atmospheric deposition of heavy metals with a very high spatial
resolution.
The most important feature of the sampling is that it correlates with the European Moss–Survey–
2000, and the results obtained will be incorporated in the Atlas of Heavy Metal Atmospheric
Deposition in Europe.
This work was supported by the grant of the Plenipotentiary of Slovak Republic at Joint Institute
for Nuclear Research. Thanks go to Dr. M. Frontasyeva and her staff.
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