ITMS code of the project: 14420100026
ENVIRONMENTAL STATE AND SUSTAINABLE MANAGEMENT
OF HUNGARIAN-SLOVAK TRANSBOUNDARY
GROUNDWATER BODIES (ENWAT)
Name of the interim report:
Specific hydrogeochemical map (intergranular transboundary
groundwater body of Quaternary sediments of the Bodrog/Bodrogköz
watershed area)
Table of Contents
1. Introduction .................................................................................................................................... 2
2. Hydrogeochemical review of the area .......................................................................................... 3
3. Methods ........................................................................................................................................... 5
3.1 Data collection..........................................................................................................................................5
3.2 Processing of hydrogeochemical data ......................................................................................................5
4. Processes affecting groundwater chemistry formation ............................................................ 11
4.1 Primary (natural) factors ........................................................................................................................11
4.2 Anthropogenic factors ............................................................................................................................13
5. Characteristics and classification of groundwater chemical composition .............................. 14
6. Characteristics of groundwater quality ..................................................................................... 24
7. Conclusion .................................................................................................................................... 30
8. Literature ...................................................................................................................................... 32
1. Introduction
Specific hydrogeochemical map of Medzibodrožie region was compiled as a partial output of
the „Environmental state and sustainable management of Hungarian-Slovak transboundary
groundwater bodies (ENWAT) “project. Basis of the map compilation represents a methodology
given in the paper by Rapant – Bodiš (2003) amended in the Slovak Directive of the Environment
Ministry of the Slovak Republic no. 9/2004 – 7 on compilation of basic hydrogeochemical map at
a scale 1:50 000. Furthermore, geological background (Baňacký et al., 1987, 1988a,b, 1989;
Kaličiak et al., 1991, 1996; Žec et al., 1997a,b) and information from the hydrogeological
investigation were used for the map preparation. The main objectives of the hydrogeochemical part
of the report (map) are as follows:

description of genesis of groundwater chemical composition,

evaluation of qualitative properties of groundwaters including an assessment of anthropogenic
influence.
Qualitative and geochemical criteria of the first groundwater aquifer represent essential part of
the hydrogeochemical map. Some other significant properties of groundwater (such as
aggressively, degree of anthropogenic contamination, content of total dissolved solids etc.) are
introduced in special thematic maps at a scale 1:150 000 (Annex 1).
The report consists of the following chapters:
 Hydrogeochemical review of the area,
 Methods (data collection, processing of hydrogeochemical data),
 Processes affecting groundwater chemistry formation (including anthropogenic factors),
 Characteristics and classification of groundwater chemical composition,
 Characteristics of groundwater quality.
Within the ENWAT project, 12 groundwater samples were collected in order to analyse
inorganic components (routine parameters, trace elements). Analyses were realized in laboratories
GAL ŠGÚDŠ in Spišská Nová Ves and MÁFI in Budapest. Organic components were determined
in two samples and analysed in laboratory GAL ŠGÚDŠ in Spišská Nová Ves. Based on the archive
data, the complete hydrogeochemical dataset represents 135 analyses of groundwaters in total.
2. Hydrogeochemical review of the area
Hydrogeochemical investigation of Medzibodrožie region strongly coincides with
hydrogeological works in the area. It concerns the regional tasks associated with a compilation of
hydrogeological and hydrogeochemical maps of the Východoslovenská nížina lowland and adjacent
areas. Hydrogeological research aimed at locating of the groundwater resources for drinking and
household purposes for population and domestic animals or monitoring of water quality at specific
site (e.g. close to the potential contamination source), respectively, were among the main objectives
of the local investigations. Former hydrogeochemical investigation in the area focused mostly on
groundwaters of the quaternary aquifers. Only negligible attention was paid to hydrogeology of the
Zemplínske vrchy Mts.
A systematic hydrogeological investigation of the area started at the beginning of the 60´s of
the last century. Within this investigation the basic information about groundwater quality and in
less extent about surface water quality has been received.
The whole investigated area was studied within the project of a baseline hydrogeological map
compilation at a scale 1:200 000 – sheet 38 Michalovce (Škvarka, Ed., 1985) and compilation of a
baseline map of chemical composition at the same scale (Gazda, Ed., 1985). The text explanations
for the baseline hydrogeological and hydrogeochemical maps (Škvarka et al., 1976) consist of an
overview of individual works realized in the area by the year 1976 together with the data on water
chemical
composition.
Within
the
baseline
hydrogeological
investigation,
regional
hydrogeochemical characteristics were summed up also in the following reports: Michalík et al.
(1995), Divinec et al. (1989), Šindler – Petrivaldský (1985), Haluška et al. (1970). In the above
mentioned reports, the assessment of the groundwater chemistry in the main hydrogeological units
and structures of the area is described in detail. Genesis of the chemical content of groundwaters
and their classification scheme according to Gazda (1975) are particularly emphasized in these
reports.
The Geochemical atlas of the Slovak Republic – Part Groundwaters (Rapant et al., 1996) has
broken the new ground in hydrogeochemistry regarding not only the assessed groundwater body but
also the whole of Slovakia. The analyses from the Geochemical atlas were widely used for the
compilation of the specific hydrogeochemical map in this report. The wider area of the
Východoslovenská nížina lowland was investigated within the project dealing with a complex
evaluation of the abiotic compartments of the environment (Puchnerová et al., 2000), during which
partial water characteristics reported in „Natural Water Quality Map“ were carried out (Kordík –
Slaninka, 2000 in Puchnerová et al., 2000).
Within the national monitoring program of the Slovak Hydrometeorological Institute
(SHMI), selected groundwater resources are observed once or twice a year (SHMI national
monitoring program: Groundwater quality in the Slovak Republic). More detailed characterization
of the quality and quantity of the monitored groundwater sites is discussed in a special report within
the ENWAT project.
Local specific investigations were also carried out in the study area. They mainly focused on a
preliminary and additional hydrogeological research of potential groundwater resources for drinking
or household purposes – Frankovič et al. (1965), Frankovič (1967), Frankovič – Hornung (1967),
Šindler (1967a,b; 1968), Bajo (1971, 1979), Bajo – Banský (1972), Tometzová (1979), Hrabková
(1983), Polák (1997), Drahoš – Tometz (1995), Michalík – Petrivaldský (1992a,b), Kačmarik
(1992), Grech – Medveďová (1992), Šindlář – Ryšková (1991), Daňková – Karoľ (1990, 1991),
Pramuk – Karoľ (1990, 1991), Nováková – Polesňák (1990), Hrabková – Grech (1990), Daňková et
al. (1989), Medveď – Medveďová (1989), Jelínek – Medveďová (1989), Bindas – Medveďová
(1987a,b), Ostrolucký (1988), Ostrolucký – Karoľ (1988), Mosej (1987), Mosej – Karoľ (1987),
Tometzová (1985), Tometzová – Karoľ (1985) and others.
Many tasks mainly of local character were specialized in the investigation of influence of
anthropogenic factors on water quality, especially in the settlements areas. Monitoring of
groundwater chemical composition, proposal of protection areas or remediation measures in case of
existing pollution source were among the main purposes of such investigations. The studies of
Orvan (1998), Dluhá – Petrivaldský (1994), Ostrolucký et al. (1986), Šťastný (1986), Lokajová –
Karoľ (1988), Tometzová – Petrivaldský (1987) and others are among very recent works.
Chemical content and quality of surface waters (some irregular sampling and analyses of
surface waters under the projects of hydrogeological investigations) and precipitations were
investigated to less extent in the Východoslovenská nížina lowland and adjacent areas. Chemical
content of snow cover has been observed nearby the Slanec, Cejkov, Remetské Hámre and Vojany
villages since 1976 – 1 sample per year (Gazda  Lopašovský, 1983; Vrana et al., 1989; Klukanová
et al., 2003; Bodiš et al., 2000).
3. Methods
3.1 Data collection
Basic hydrogeochemical dataset consists mainly of chemical analyses of inorganic
components of groundwater. Within the ENWAT project, 12 groundwater samples were collected
and analysed (comprehensive analyses of inorganic and organic components). The chemical
analyses were realized in laboratories of GAL ŠGÚDŠ in Spišská Nová Ves and MÁFI in Budapest.
For the compilation of the specific hydrogeochemical map, the archival database of analyses from
the Geochemical atlas of the Slovak Republic – part Groundwaters (Rapant et al., 1996) was used –
135 samples in total analysed in laboratory of INGEO corporation Žilina between 1992 and 1993.
Groundwater samples were collected under stable climatic conditions and analysed by
standard analytical procedures. The measures in the field comprise: pH, water and air temperature,
conductivity, content of dissolved oxygen, alkalinity 8.3 and acidity 4.5. After the sampling
procedure, chemical stabilization of water samples was carried out meeting the laboratory claims. A
review of analytical techniques applied to individual variables is given in Tab. 3.1. The table also
shows detection limits of the techniques and reliability intervals of analytical results of Žilina-based
INGEO corporation laboratory. The accuracy of analytical data was assured by the system of
analytical quality assurance (AQA) corresponding to the European standards of the series EN 45
000 and to the principles of appropriate laboratory practice. Results of internal control analyses in
Žilina-based INGEO corporation laboratory showed very low variability between the concentrations
of individual routine parameters determined in the control analyses which coincide with accuracy
and sensitivity of used analytical methods and instruments.
3.2 Processing of hydrogeochemical data
A comprehensive assessment and description of chemical content and qualitative properties of
groundwaters are the main objectives of the hydrogeochemical synthetic map (Rapant – Bodiš,
2003). The map conveys basic scientific background for characteristic of groundwater quality and
status of groundwater contamination to serve the purpose of rational usage and protection of
groundwater. Topography (river system, level lines, settlements etc.) represents a base of the map.
The main spatial layers of the map are characterized by three basic hydrogeochemical criteria:

qualitative,

geochemical,

water management.
Tab. 3.1
A review of techniques, their detection limits, reliability intervals at concentrations
close to ten times their detection limit and used analytical instruments
Element
compound
Na
K
Mg
Ca
SiO2
NH4
F
Cl
NO3
SO4
HCO3
PO4
Fe
Mn
Cr
Cd
Pb
As
Se
Cu
Al
Zn
Hg
Sb
Ba
Li
Sr
CODMn
agress. CO2
Notes:
ICP – OES
AAS – F
SPFM
AAS – ETA
ISE
AAS – CV
ITPH
AAS –MHS
T
Detection limit
(mg.l-1)
0,1
0,1
1
1
0,5
0,05
0,1
0,1
0,5
0,3
0,1
0,05
0,01
0,005
0,0005
0,0005
0,001
0,001
0,001
0,0005
0,01
0,001
0,0002
0,0002
0,01
0,002
0,01
0,08
2,2
Method
AAS - F
AAS - F
ICP – OES
ICP – OES
SPFM
SPFM
ISE
T
ITHP
ITHP
T
SPFM
ICP - OES
ICP - OES
AAS - ETA
AAS - ETA
AAS - ETA
AAS - MHS
AAS - MHS
AAS - ETA
ICP - OES
AAS - F
AAS - CV
AAS -MHS
ICP - OES
ICP - OES
ICP - OES
T
T
Reliability interval
(mg.l-1)
± 0,2
± 0,2
± 0,5
± 0,75
± 0,55
± 0,02
± 0,015
± 0,3
± 0,4
± 0,5
± 2,1
± 0,01
± 0,01
± 0,005
± 0,0006
± 0,0004
± 0,001
± 0,0005
± 0,0006
± 0,0007
± 0,01
± 0,002
± 0,0002
± 0,0003
± 0,005
± 0,002
± 0,005
± 0,1
± 4,62
optical emission spectrophotometry – induction bounded plasma
fire atomic absorption spectrophotometry
spectrophotometry
atomic absorption spectrophotometry - electrothermic atomization
ion selective electrodes
atomic absorption spectrophotometry - cold vapour
isotachophoresis
atomic absorption spectrophotometry - hydride-generation method
acidobasic titrations
Dot signs indicating the groundwater sampling sites on the map specify also the type of
groundwater source and range of chemical analysis, respectively. Supplementary hydrogeochemical
characteristics (groundwater of anomaly quality, character of pollutants and significant components
in groundwater) are presented by specific symbols. Contours mark mainly areas exhibiting much
higher concentrations of contaminants than the drinking water standards, areas recommended for
more detailed investigation and others. Some other significant groundwater properties (aggressively,
contamination degree, distribution of dissolved solids etc.) are displayed in special contour maps at
a scale 1:150 000 (Annex 1).
Qualitative characteristics of groundwaters
Groundwater quality properties are represented by the quality classes A-H (8 different colour
shades in the hydrogeochemical map). Determination of groundwater quality classes is based on
concentrations of chemical parameters grouped according to their increasing toxicity and water
treatment processes. The standard values for determination of groundwater quality correspond to the
limit values under the Directive of the Slovak Government no. 354/2006 on demands on water for
human consumption. The specific groundwater quality of areas is based on the groundwater quality
of individual samples (minimum 80% of groundwater with the same quality is requested). A special
symbol is used to show the groundwater with significantly different quality in comparison to the
quality given for the surrounding area (difference of two or more classes). More detailed definition
of groundwater quality is given on the map legend.
Geochemical characteristics of groundwater
Characteristics of the groundwater chemistry are based on the determined hydrogeochemical
groups allocated on the map by black raster. The defined hydrogeochemical groups are subject to
the natural conditions of the groundwater regime and are based on :

Type of water genesis,

Water chemical type,

Content of total dissolved solids,

Character of geology and permeability of aquifer.
Groundwater genesis expresses origin of dissolved solids in water. Natural (Gazda, 1974)
and anthropogenic (Rapant, 2001) origin of concentration of elements and compounds is
distinguished as well. The chemical type of groundwater is characterized by prevailing ion content
via symbols of dominant elements/compounds based on the results of chemical analyses (routine
parameters Na, K, Ca, Mg, NO3, Cl, SO4, HCO3). Equivalent contribution of cations and anions
higher than 25 mmol.z % (of their sum 100%) is a significant criterion for determination of
chemical type. Every element/compound is arranged according to its equivalent rate (e.g. Ca-MgHCO3-SO4 with the highest Ca2+ content on the left side and the highest SO42- content on the right
side). Intervals of the total dissolved solids content are based on the mathematical-statistical
processing of the data.
Groundwater genesis is closely interconnected with the geological setting of the observed
areas. Determination and spatial delineation of hydrogeochemical groups was realized on the basis
of information collected from the geological mapping programmes and a compiled digital
geological map (Baňacký et al., 1987, 1988a,b, 1989; Kaličiak et al., 1991, 1996; Žec et al.,
1997a,b).
Database of groundwater chemical content
Database of groundwater chemical content is a key part of the hydrogeochemical map. The
information from the database is interactively connected with the map (dot entities on the map
represent locations of groundwater sampling). Basic principles of hydrogeochemical database
processing were elaborated by Kordík & Slaninka (2005a, 2006 unpublished, respectively). Several
limitations had to be taken into consideration when dealing with the database (e.g. classification &
structuring of the fields) – different sources of information, different timing of the chemical
analyses, different laboratories applying various methods of chemical analyses etc. Because of
complex character of geochemical information it is very beneficial if a relational database is built
up.
The database of groundwater samples used for the hydrogeochemical map compilation
consists of 135 chemical analyses with more than 5000 records stored and processed by MS Access
software package.
Graphical execution of hydrogeochemical map
The overall map output (original) is elaborated in MapInfo Professional software package.
The program itself enables to handle the data input, storage, processing and analyses as well as
interactive relation of graphical information with the database system (MS Access).
Creating of contour maps
The final output of contour maps of selected chemical parameters at a scale 1:150 000 was
processed in MapInfo Professional software package. Interpolation was calculated in Surfer for
Windows software package using the inverse distance method (1/D2) with a searching radius of 10
km. Surflink interface was used to transfer the interpolated data into the MapInfo Professional.
Statistical analysis
Basic statistical analysis of groundwater data was executed in MS Excel and SPSS software
packages. Graphical visualization of some statistical results was made in Grapher software package.
In case of concentrations of chemical parameter below quantification limit of the analytical method,
half value of the limit was involved in the statistical calculation. In case of repeated measurements
(monitoring) at the groundwater sampling site, a median from all laboratory measurements was
taken into consideration when processing the data (median gives the value more resistant to
influence of outliers). Statistical analysis consists of:

Basic statistical evaluation,

Comparative statistics – correlation analysis of selected chemical parameters.
Typical statistical parameters such as mean, median, standard deviation, minimum and
maximum, determine basic characteristics and verification of the data set. Frequency table and
histogram verifying the distribution character of the total dissolved solids content are also presented
for all groundwater resources.
Correlation analysis to assess a relationship of chemical compounds and other selected
parameters in groundwaters was also carried out. Since distribution character of most chemical
parameters doesn’t meet normality criteria and results of linear Pearson correlation can be partially
distorted, nonparametric Spearman correlation was also calculated. The correlation analysis was
calculated for all groundwater sampling sites.
Calculation of contamination index
Apart from groundwater quality in the hydrogeochemical map (colour in area), the
contamination character of groundwaters is also presented through so called contamination index Cd
(Backman et al., 1998):
n
C  C
d
where
i 1
fi
where
C
fi

C
C
Ai
 1,
Ni
Cd – level of sample contamination (contamination index),
Cfi – contamination factor for the i-th component,
CAi – analytical value of the i-th component,
CNi – normative value of the i-th component.
Contamination factor is calculated for each analysed compound according to the Directive of
the Slovak Government no. 354 from 10 May 2006 on demand to water intended for human
consumption and quality control of water intended for human consumption. Overall calculation of
contamination degree (sum of contamination factors of individual compounds) consists only of the
parameters exceeding the normative values (i.e. positive values only). For the sampling sites with no
chemical parameter exceeding the normative value, the zero value was assigned.
4. Processes affecting groundwater chemistry formation
4.1 Primary (natural) factors
Groundwater chemistry formation of the study area is a complex process that takes place in
different phases of the hydrological-hydrogeological water cycles. Chemical composition of
meteoric waters (precipitations) and surface waters represents the initial stage of the entire system of
the groundwater chemistry formation. Particular stages, where the chemical compositions of initial
water are modified, include vegetation, soil profile and rock environment. Moreover, compounds of
an anthropogenic origin are significant and common in the investigated area. Generally, the most
important natural factors controlling the formation of groundwater chemistry are as follows:
 amount and physico-chemical properties of precipitations or surface waters, respectively, the
waters entering the groundwater system,
 character of vegetation and soil cover (composition of soil atmosphere, content of organic
substances, mineralogical structure and microorganism activity),
 mineralogical-petrographic properties of the rock environment and character of its
permeability (mostly intergranular permeability),
 hydrodynamic, thermodynamic, oxidation-reduction conditions of natural water regime and
duration of its water-rock interaction,
 secondary processes of water alteration – that is mixing and ion-exchange processes.
Precipitation quality
Chemical composition of precipitations in the area was observed in winter snow cover. The
whole profile of snow cover is usually sampled and determines a chemical content of aqueous
solutions originating from melted snow, including dry deposition. Dissolved and suspended
substances in precipitations predominantly reflect: dissolving of atmospheric gases of natural origin,
composition of aerosols of marine origin and terrigenous dust and products of anthropogenic
activities.
In the existing geographic-climatic conditions of the region, chemical composition of
precipitations mostly reflects origin of air masses, global and local contamination of the atmosphere
and character of dry fallout.
Snow quality within the monitoring program of snow cover of Slovakia (Vrana et al., 1989;
Bodiš et al., 2000; Bodiš et al., 2003 in Klukanová et al., 2003) is not directly observed in the area.
On the other hand, nearby the region, the snow cover is regularly monitored in the vicinity of
Cejkov, Vojany and Slanec villages.
Mixed chemical composition is very typical of snow precipitations and series of Ca-NH4-NaMg-HCO3-Cl-NO3-SO4 ions were set up according to their occurrence at the monitoring sites.
Winter precipitation usually shows a significantly strong acid reaction (pH is mostly within the
range of 4,4 to 4,9). This, so called acid rainfall, consists of free acids and potentially impacts
mineralization processes in the rock environment. The chemical composition of the precipitation in
the area corresponds mainly to global content of the atmosphere. Anthropogenic influence on
dissolved solid contents from the corresponding atmosphere conditions was observed in snow
locally (Kordík – Slaninka, 2000 in Puchnerová et al., 2000).
Soil cover
Chemical composition of infiltrated rain waters is significantly modified in the soil layers.
The alteration of chemistry strongly coincides with permeability and thickness of soil cover, soil
type, altitude, season, content of organic substances, presence of chemical parameters etc. Based on
several experimental measurements (e.g. Mayer, 1971; Bublinec, 1973; Rapant, 1994; Pitter, 1990),
multiply increase of concentrations of the main cations and anions as well as serious rise in total
dissolved solids content in the water is expected after passing through the soil structure.
Soil cover is a significant source of CO2 that is formed mostly as a result of biochemical
decomposition of organic material, life activity of microorganisms and production of root system in
plants and trees. Besides CO2, the soil is also the source of other inorganic (NH4, NO2, NO3) and
organic compounds (humid acids, fulvous acids). Partial dissociation of humin acids supplies
transition rain waters with other active ions H+ thereby increasing the total hydrolytic capacity.
Water-rock interactions
Groundwaters of the area and their genesis have a close relation to mineral composition of the
rock setting. It means, that the water-rock interactions form the major and typical part of the
groundwater chemical content. Consequent character of these reactions (dissolving of carbonate
minerals, hydrolytical decomposition of silicate minerals, oxidation-reduction processes etc.) is
conditioned by mineralogical-petrographic properties of the rock environment, which determine
genetical types and therefore also chemical composition of groundwaters in the region. Water-rock
interactions, their mechanism and kinetics were described in detail by many authors, e.g. Garrels
(1960), Gazda – Kullman (1964), Gazda (1965), Pačes (1983), Pitter (1990) and others.
Other natural genetical factors affecting the water chemistry formation (mostly hydrodynamic
conditions) are crucially influenced by specific physico-geographical conditions of the region
(mostly relief type). Relatively monotonous plain character of landscape results in slow groundwater
and surface water flow and consequently in relatively longs retaining period of natural waters and
more intensive water-rock interactions (significant increase of values of total dissolved solids is
typical).
4.2 Anthropogenic factors
Noteworthy increase in negative effects of anthropogenic activities on the natural environment
has been observed in the last decades. The most extent detrimental impact practically in the whole
area of the Východoslovenská nížina lowland is produced by intensive long-term agricultural
activity and livestock breeding. The activities result in a significant deterioration of groundwater
quality in the region (mostly due to high concentrations of nitrogen species in the natural system).
Emission of gas and solid contaminants is widespread in some parts of the region (e.g. effect
of the Vojany power plant and others). Negative impact of settlements on natural water quality is
likely to appear in the area. Sewage system is missing in many villages and in many cases drain
mouth of the canalization makes its way directly into the water body.
Dumping sites of municipal waste are among potential contamination sources. Many
registered waste deposits are unlicensed, without operational regime and service. Except from rough
intervention into the landscape morphology, the dumps pose potential threat to groundwater and
surface water quality as well. Potential contamination sources are discussed in detail in a special
report within the ENWAT project.
5. Characteristics and classification of groundwater chemical composition
Characteristics of groundwater chemical composition is based on the results of groundwater
chemical analyses and confronted by the knowledge of natural conditions of the investigated area.
Groundwater chemical composition of the quaternary fluvial aquifers of the Ondava, Laborec,
Uh, Latorica, Bodrog and Roňava rivers and strážňansko-trakanská depression in Bodrog region
was based on the archive analyses elaborated by Jetel et al. (1998). The results indicate significant
differences in levels of total dissolved solids among individual characterized areas, even within the
same aquifer (average values range in 350-650 mg.l-1). Certain decrease of groundwater
mineralization in the fluvial sediments down the Latorica river has not been explained yet. The
chemical composition of Ca-HCO3, in less extent Ca-Mg-HCO3 and Ca-Na-HCO3 water types
dominate the area. Furthermore, based on the results, a relatively high contribution of chlorides and
sodium was documented in groundwaters of the quaternary sediments. They likely originate from
raising the deeper horizons of Neogene formation characterized by higher Na-Cl contents. On the
other hand, anthropogenic influence can also support the above mentioned trend.
Groundwaters of the investigated area, especially of the first quaternary aquifer, are mostly of
an atmospheric origin, i.e. precipitation plays key role in their replenishing. Groundwater chemistry
is considerably controlled by the natural conditions as well as by the secondary (anthropogenic)
factors affecting the groundwater chemistry in the area. Generally two basic groundwater types are
formed in the region. The waters, the chemical compositions of which closely coincide with the
mineralogic-petrographic character of the particular rock settings of their circulation are qualified as
petrogenous, according to genetic classification of groundwaters of the Western Carpathian (Gazda,
1974), or groundwaters with petrogenous dissolved solids contents, respectively. The second
groundwater group prevailing in the area represents so-called fluvial waters of the main river
sediments of the Latorica, Tisa and Bodrog rivers. Surface waters characterized by temporal and
spatial variability of dissolved solids contents are considered as a main source of those
groundwaters.
Strong variability of values of total dissolved solids, evident in groundwaters, indicate a
complexity of hydrogeochemical conditions of groundwater chemistry formation. Values of total
dissolved solids in groundwaters of shallow regime mostly range between 400-1600 mg.l-1,
exceptionally reaching more than 2000 mg.l-1 (tab. 5.1, fig. 5.1).
Tab. 5.1
Frequency table of total dissolved solids values – data of all groundwater sampling
sites
Total dissolved
solids (mg.l-1)
400
650
800
1000
Frequency
Cumulative %
7
14
22
18
5,19
15,56
31,85
45,19
18
58,52
1200
Total dissolved
solids (mg.l-1)
1400
1600
1800
2000
More than
2000
Frequency
Cumulative %
18
14
9
6
71,85
82,22
88,89
93,33
9
25
100,00
120.0%
100.0%
20
80.0%
početnosť
15
60.0%
10
40.0%
5
20.0%
More
2000
1800
1600
1400
1200
1000
800
600
.0%
400
0
celková mineralizácia (mg.l -1)
Fig. 5.1
Histogram of total dissolved solid contents
Groundwaters with petrogenous mineralization
Chemical composition of groundwaters is formed chiefly as a result of dissolution of
carbonates and hydrolytical decomposition of silicate minerals, in less extent as a result of oxidation
of sulphides, dissolution of gypsum or halite, ion-exchange reactions and biochemical processes. As
a results the following hydrogeochemical groundwater groups with petrogenous mineralization can
be distinguished:
 groundwaters of silicatogenic dissolved solid contents with circulation in the Paleozoic rock
formation of the Zemlínske vrchy Mts. (north-west boundary of the area),
 groundwaters of silicatogenic, in less extent silicatogenic-sulphidogenic dissolved solid
contents with circulation in the Neogene volcanites (nearby the Kráľovský Chlmec town),
 groundwaters of carbonatogenic dissolved solid contents with circulation in the Mesozoic
carbonatic rocks of the Zemplínske vrchy Mts.
Groundwaters with petrogenous mineralization cover only a tiny part of the area. Dataset
consists of a small number of measurements (analyses) and thus no statistic evaluation is given in
the report.
Groundwaters with fluvial mineralization
Groundwaters with the fluvial mineralization occur in the fluvial flats of the all main rivers
(Bodrog, Latorica, Tisa) and dominate the area. The fluvial sediments (mostly gravels and sands
overlaid usually by clays and floodplain mud) of the Laborec, Ondava and Roňava rivers achieve
the highest thickness (up to 30-35 m) within the area of Eastern Slovakia. They are occasionally
even 60 m thick in the neotectonic depressions.
Formation of groundwater chemical composition has several specifics if compared to the
groundwaters with the petrogenous mineralization. As a main source of their replenishment we can
expect not directly penetrated rain waters but percolated surface and slope waters or waters from the
deeper horizons, respectively. Both significant temporal and spatial variability of dissolved solids
contents characterize that infiltrated waters. Moreover, a close hydraulic interconnection between
the fluvial groundwaters and the surface course is very typical resulting into the temporal and spatial
alteration of the regime. Presence of more or less independent parallel flows of that groundwater
with the river system is frequent as well. Surface course can sometimes contribute to the alluvial
sediments and next time has the draining effect. Consequently, the chemical composition of the
fluvial groundwater is then defined by mixing of waters with variable chemical composition as well
as by already mentioned mineralization processes running in the system of fluvial gravel (sand)water.
Summary statistics of the groundwater chemical composition of the complete dataset
(represented practically by the groundwaters with the fluvial mineralization) is given in Tab. 5.2.
Strong variability of all observed key chemical parameters is evident in groundwaters. This fact
reflects mostly heterogeneity of the rock environment of the corresponding groundwater circulation
as well as complexity of hygrogeological and hydrogeochemical conditions of the chemical
composition formation.
Unpolluted natural groundwaters of the Latorica, Uh, Medzibodrožie and Tisa fluvial
sediments (south-east part of the Východoslovenská nížina lowland) are predominantly of Ca-MgHCO3-(SO4) type with the contents of dissolved solids ranging between 500-800 mg.l-1. However,
chemical composition of the most of the groundwater samples is strongly metamorphosed (due to
man-made origin). Because of prevailing water-rock interactions, the main significant A2 and the
less significant Ca-HCO3, and Ca-Mg-HCO3 types of chemical content dominate (almost 40%
samples) the groundwater of the first aquifer. Average contribution of A2 component is 47.9
equivalent % - Tab. 5.2. In more than 1/3 of groundwater samples, a higher contribution of S2(SO4)
component (above 25 equivalent %) was observed. Around 20% of sampling sites is represented by
A2-S2(SO4) transient type of chemical composition. Anthropogenic influence on groundwater
chemical composition is indicated by abundant presence of groundwaters with the different transient
and mixed groundwater chemical types. Different contribution of chemical compounds Na-K-CaMg-HCO3-SO4-NO3-Cl is characteristic for those waters. Contents of total dissolved solids reach
values of about 1000-1500 mg.l-1 (with an average value of 1128.6 mg.l-1 for the whole dataset).
Origin of groundwaters with the mixed chemical composition in the investigated area relates
to the specific genetic factors – mostly a concurrent impact of more mineralization processes,
mixing of waters with a different origin, leakage of deep waters along the fracture zones and
tectonic lines etc. and last but not least significant influence of anthropogenic factors.
Deeper aquifers of neogene sediments are usually characterized by groundwaters of
hydrosilicatogenic dissolved solid contents. These petrogenous waters are formed in the conditions
of relatively shallow circulation and the Na-HCO3 chemical type. Groundwaters of Na-Cl-HCO3
and Na-Cl types of chemical composition originate exclusively in the deep aquifers and represent
relict sea water in different level of biogenic and petrogenous alteration (Michalíček, 1965a,b).
Occurrence of Na-Cl brines is specific feature of salty formations of the Karpat and Baden
geological structures. Occurrence of Na-HCO3 and Na-Cl water types can address a standard
vertical hydrogeochemical zonality considering: a) the genetic factors as a function of deep
temperature and pressure conditions, b) migration and conservation of water with allochtonous
origin in relation to the rock structure and c) factors of intrinsic evolution of stagnant solutions.
Following the archive documents, contents of total dissolved solids in waters of halogenous
mineralization reach up to 300 g.l-1. During the pumping test in the borehole Stretava-5 (horizon
2991-3013 m), the salt and water suspension with the content of total dissolved solids (liquid phase)
of about 464 g.l-1 was exploited (Michalíček, 1965a,b). The groundwater of the deeper aquifers is
not presented in the specific hydrogeochemical map.
Tab. 5.2
Basic statistical parameters of groundwater chemical composition of all samples used
for hydrogeochemical map compilation
All samples
Standard
n
average
median
deviation
minimum
physico-chemical parameters (except of displayed units and pH in mg.l-1)
135
13.2
12.8
1.8
10.4
Water temperature (oC)
135
7.05
7.03
0.33
6.32
pH
135
1128.6
1059.4
524.7
371.0
Total dissolved solids
135
4.99
4.36
2.64
0.97
Hardness (mmol.l-1)
135
4.5
4.3
2.1
0.8
O2
135
3.13
2.56
1.51
0.80
CODMn
135
0.021
0.013
0.024
0.002
Li+
135
61.28
51.00
44.00
10.60
Na+
135
74.05
11.80
107.70
0.30
K+
135
141.57
125.85
74.75
26.45
Ca2+
135
35.35
31.13
21.93
7.54
Mg2+
135
0.51
0.45
0.29
0.07
Sr2+
135
0.042
0.005
0.237
0.005
Fetotal
135
0.445
0.044
0.846
0.003
Mn
135
0.048
0.025
0.061
0.025
NH4+
135
0.128
0.110
0.083
0.050
F135
81.03
60.99
67.31
8.33
Cl135
164.17
149.25
108.86
3.83
SO42NO2135
135.42
86.70
155.39
0.25
NO3135
1.466
0.040
3.759
0.005
PO43135
404.6
388.7
172.6
70.8
HCO3135
22.45
19.50
9.39
6.58
SiO2
135
62.5
57.2
36.8
2.2
Free CO2
133
0.31
0.00
1.91
0.00
Aggressive CO2
135
0.0007
0.0003
0.0012
0.0003
Cr
135
0.0030
0.0021
0.0039
0.0003
Cu
135
0.7817
0.2210
1.6640
0.0020
Zn
135
0.0019
0.0005
0.0045
0.0005
As
135
0.0003
0.0003
0.0002
0.0001
Cd
135
0.0040
0.0020
0.0060
0.0002
Se
135
0.0009
0.0005
0.0009
0.0004
Pb
135
0.00011
0.00010
0.00007
0.00010
Hg
133
0.0805
0.0700
0.0455
0.0200
Ba
135
0.0776
0.0300
0.1651
0.0050
Al
135
0.0002
0.0001
0.0005
0.0001
Sb
Al filtered
Palmer-Gazda characteristics (%)
135
26.0
23.9
13.4
4.6
S1
135
22.8
19.5
21.4
0.0
S2
135
47.9
46.8
18.3
11.7
A2
135
15.4
17.6
12.8
0.0
S2(SO4)
characterization coefficients (-)
135
0.516
0.340
0.499
0.050
r(Na+rK)/r(Mg+rCa)
135
0.415
0.390
0.139
0.140
rMg/rCa
135
0.109
0.110
0.047
0.010
rSO4/M
130
8.541
5.042
9.515
0.094
Contamination degree
maximum
19.4
8.10
2747.7
13.36
9.8
8.32
0.203
215.00
520.00
405.61
116.74
1.74
2.088
4.513
0.430
0.620
334.65
559.31
794.60
20.500
989.7
63.73
275.0
17.60
0.0093
0.0380
11.7130
0.0410
0.0020
0.0310
0.0090
0.00090
0.3000
1.4500
0.0053
62.9
74.2
87.3
51.9
2.850
0.940
0.260
55.791
Correlation analysis
Relation between chemical parameters and selected chemical characteristics in groundwaters
is evaluated via correlation analysis. Apart from linear Pearson correlation (tab. 5.3) also
nonparametric Spearman correlation was calculated (tab. 5.4). Use of nonparametric methods in
statistics is recommended for data sets that don’t fit the normal distribution. It was shown that the
Spearman correlation is suitable statistical tool for the chemical parameters staying in
disequilibrium with deviation from the normal distribution character. Nonparametric Spearman
method is also more robust to influence of outliers or extreme values.
Correlation matrix was calculated for all the obtained data. Considering a large data set,
correlation coefficient K at the level of about 0.3 is statistically significant at two-tiled significance
level <0,01. Light grey colour raster emphasizes the correlation coefficients higher than 0.3 and
dark grey colour raster highlights the correlation coefficient lower than –0.3.
Correlation analysis demonstrates the following facts:
 Total dissolved solids contents in groundwaters is mostly affected by concentrations of the main
ions Na+, K+, Ca2+, Mg2+, Cl-, SO42-, NO3- and HCO3- (a strong linear cross correlation among
the parameters clearly supports this fact). These ions usually correlate also each other and
indicate their common origin as well as occurrence in groundwaters. No elimination of abovementioned dependence is obvious in Spearman nonparametric calculation. It can be assumed that
the outliers in the statistical dataset don’t play an important role in the correlation results.
 A close positive correlation was calculated between Cl- a NO3- components. Common occurrence
of these ions in low concentrations is nothing exceptional in groundwaters because of their
appearance in the source (rain) waters (marine origin or origin from the technosphere). Higher
contents of these ions particularly in the Východoslovenská nížina lowland are put down to manmade activities. Na-Cl component can also originate from the deeper aquifer horizons.

Significant correlation between K+ and PO43- reflects anthropogenic origin likely from the
agricultural activities (N, P, K from fertilizers). Although any meaningful correlation of NO3with those parameter has not been calculated, the fact that the nitrates significantly contribute to
content of dissolved solids in groundwaters, indicates an impact of agricultural activities on
groundwater quality.
 Influence of carbonate balance on groundwater pH values is evident in the negative correlation of
pH value with free CO2 concentration (mostly in Spearman correlation). Generally, presence of
free CO2 decreases the pH value of water. After CO2 is released from water, increase of pH
values is observed. Rise in tenths of pH units is typical mainly in surface waters.
 Significant correlations observed among some trace elements can be hardly interpreted due to
their very low concentrations (in most cases under the quantification limit).
 Values of contamination degree are mostly influenced by concentrations of Mn, Cl-, SO42and NO3-. (positive correlations were calculated).
Characteristic of chemical composition is displayed in fig. 5.2 as an adapted Piper diagram.
Relatively scattered values of total dissolved solids as well as variable concentrations of all main
components are typical of groundwaters in the investigated area.
Tab. 5.3
Linear (Pearson) correlation matrix of analyzed parameters from all groundwater samples
pH
O2
ChSK
Li
Na
K
Ca
Mg
Sr
Fe
Mn
NH4
F
Cl
SO4
NO3
PO4 HCO3 SiO2 vCO2 aCO2
Cr
Cu
Zn
As
Cd
Se
Pb
Hg
Ba
Al
Sb
S1
S2
A2
st.zn.
mineralizázia
1.00
pH
0.06
O2
-0.18
ChSKmn 0.61
Li
0.46
Na
0.78
K
0.51
Ca
0.75
Mg
0.78
Sr
0.73
Fe
-0.04
Mn
0.03
NH4
-0.03
F
0.21
Cl
0.84
SO4
0.84
0.06
1.00
0.05
0.21
0.15
0.05
0.20
-0.10
-0.06
-0.09
-0.01
-0.21
-0.02
0.18
-0.09
-0.03
-0.18
0.05
1.00
-0.28
-0.06
-0.16
-0.07
-0.11
-0.20
-0.13
-0.05
-0.17
-0.10
-0.06
-0.12
-0.13
0.61
0.21
-0.28
1.00
0.35
0.46
0.57
0.25
0.39
0.29
0.02
-0.01
0.19
0.21
0.41
0.40
0.46
0.15
-0.06
0.35
1.00
0.24
0.71
0.05
0.11
0.05
-0.02
-0.16
-0.02
0.15
0.30
0.18
0.78
0.05
-0.16
0.46
0.24
1.00
0.22
0.53
0.66
0.64
0.00
0.07
0.00
0.29
0.74
0.76
0.51
0.20
-0.07
0.57
0.71
0.22
1.00
-0.09
0.01
-0.08
0.01
-0.04
0.03
0.18
0.21
0.12
0.75
-0.10
-0.11
0.25
0.05
0.53
-0.09
1.00
0.79
0.86
-0.07
0.07
-0.06
-0.04
0.82
0.82
0.78
-0.06
-0.20
0.39
0.11
0.66
0.01
0.79
1.00
0.85
-0.02
0.07
-0.06
0.20
0.74
0.81
0.73
-0.09
-0.13
0.29
0.05
0.64
-0.08
0.86
0.85
1.00
-0.05
0.14
-0.06
0.13
0.77
0.81
-0.04
-0.01
-0.05
0.02
-0.02
0.00
0.01
-0.07
-0.02
-0.05
1.00
0.01
-0.01
0.07
0.00
-0.04
0.03
-0.21
-0.17
-0.01
-0.16
0.07
-0.04
0.07
0.07
0.14
0.01
1.00
0.31
-0.04
0.21
0.06
-0.03
-0.02
-0.10
0.19
-0.02
0.00
0.03
-0.06
-0.06
-0.06
-0.01
0.31
1.00
-0.04
0.06
0.01
0.21
0.18
-0.06
0.21
0.15
0.29
0.18
-0.04
0.20
0.13
0.07
-0.04
-0.04
1.00
0.00
0.07
0.84
-0.09
-0.12
0.41
0.30
0.74
0.21
0.82
0.74
0.77
0.00
0.21
0.06
0.00
1.00
0.82
0.84
-0.03
-0.13
0.40
0.18
0.76
0.12
0.82
0.81
0.81
-0.04
0.06
0.01
0.07
0.82
1.00
0.71
-0.01
0.02
0.25
0.31
0.50
0.22
0.69
0.57
0.57
-0.04
-0.11
-0.12
-0.10
0.66
0.65
0.09
0.15
0.12
0.25
0.24
0.06
0.40
-0.18
-0.17
-0.26
-0.02
-0.15
-0.03
-0.18
-0.03
0.00
0.61
0.16
-0.28
0.60
0.36
0.45
0.55
0.24
0.44
0.33
-0.03
0.05
-0.01
0.50
0.28
0.30
-0.24
-0.15
0.22
-0.14
0.06
-0.24
0.01
-0.26
-0.32
-0.35
0.07
-0.16
-0.07
-0.19
-0.20
-0.25
0.32
-0.40
-0.35
0.25
0.00
0.17
0.04
0.38
0.40
0.37
0.03
0.20
0.01
0.06
0.35
0.25
-0.14
-0.10
0.15
-0.05
-0.04
-0.12
-0.05
-0.12
-0.11
-0.17
-0.02
-0.08
-0.03
-0.10
-0.08
-0.09
0.09
0.05
-0.05
0.02
0.10
0.09
0.08
0.02
0.07
-0.04
0.05
-0.12
0.03
0.02
0.01
0.14
0.25
0.04
-0.01
0.38
0.21
0.17
0.37
0.00
0.07
0.02
0.01
-0.02
0.03
0.21
0.08
0.18
0.10
-0.14
-0.19
0.00
0.06
0.07
-0.04
0.11
0.15
0.12
-0.05
0.13
0.21
0.02
0.14
0.21
0.08
0.15
0.05
0.14
0.16
0.02
0.25
-0.07
-0.09
-0.15
0.08
-0.07
-0.06
-0.14
0.00
0.04
0.00
-0.22
-0.05
-0.10
0.03
-0.03
-0.06
0.07
0.02
0.04
-0.07
-0.09
-0.07
-0.02
0.05
0.03
0.24
-0.03
0.06
0.17
0.22
0.14
0.35
0.03
0.03
0.01
-0.09
-0.17
-0.06
0.04
0.05
0.11
0.14
0.08
-0.13
0.28
0.32
0.10
0.27
-0.07
0.04
-0.07
-0.03
-0.11
0.00
0.28
0.01
-0.04
0.06
-0.03
-0.16
0.06
0.09
0.00
-0.01
0.03
0.21
0.03
0.16
-0.06
-0.01
-0.01
0.00
0.12
-0.01
-0.21
0.08
-0.12
-0.02
-0.14
-0.08
0.13
0.02
-0.02
0.37
0.09
-0.07
-0.15
0.10
-0.06
-0.08
0.10
-0.06
-0.04
-0.05
-0.09
-0.01
-0.09
-0.07
-0.04
0.10
-0.08
-0.07
0.02
-0.12
-0.12
0.07
0.09
-0.06
0.12
0.06
0.04
0.07
0.04
0.02
0.00
0.07
-0.07
-0.04
-0.09
0.02
0.08
0.46
0.26
-0.15
0.53
0.48
0.51
0.75
-0.12
0.05
-0.03
0.10
-0.02
0.07
0.17
0.24
0.25
0.21
-0.23
0.04
-0.18
-0.15
0.11
-0.44
0.64
0.42
0.50
-0.04
-0.06
-0.03
-0.25
0.44
0.51
-0.60
0.05
0.10
-0.26
-0.32
-0.50
-0.23
-0.54
-0.44
-0.44
-0.01
0.10
-0.03
0.08
-0.62
-0.69
0.36
-0.12
-0.09
0.20
0.06
0.30
0.20
0.27
0.24
0.27
0.04
0.81
0.23
-0.13
0.46
0.33
NO3
0.71
PO4
0.09
HCO3
0.61
SiO2
-0.24
vCO2
0.32
agr.CO2 -0.14
Cr
0.09
Cu
0.25
Zn
0.10
As
0.08
Cd
0.00
Se
0.24
Pb
0.14
Hg
0.06
Ba
-0.01
Al
-0.08
Sb
0.07
S1
0.46
S2
0.21
A2
-0.60
stupeň zneč.
0.36
-0.01
0.15
0.16
-0.15
-0.40
-0.10
0.05
0.04
-0.14
0.15
-0.22
-0.03
0.08
-0.03
-0.21
0.10
0.09
0.26
-0.23
0.05
-0.12
0.02
0.12
-0.28
0.22
-0.35
0.15
-0.05
-0.01
-0.19
0.05
-0.05
0.06
-0.13
-0.16
0.08
-0.06
-0.06
-0.15
0.04
0.10
-0.09
0.25
0.25
0.60
-0.14
0.25
-0.05
0.02
0.38
0.00
0.14
-0.10
0.17
0.28
0.06
-0.12
-0.04
0.12
0.53
-0.18
-0.26
0.20
0.31
0.24
0.36
0.06
0.00
-0.04
0.10
0.21
0.06
0.16
0.03
0.22
0.32
0.09
-0.02
-0.05
0.06
0.48
-0.15
-0.32
0.06
0.50
0.06
0.45
-0.24
0.17
-0.12
0.09
0.17
0.07
0.02
-0.03
0.14
0.10
0.00
-0.14
-0.09
0.04
0.51
0.11
-0.50
0.30
0.22
0.40
0.55
0.01
0.04
-0.05
0.08
0.37
-0.04
0.25
-0.06
0.35
0.27
-0.01
-0.08
-0.01
0.07
0.75
-0.44
-0.23
0.20
0.69
-0.18
0.24
-0.26
0.38
-0.12
0.02
0.00
0.11
-0.07
0.07
0.03
-0.07
0.03
0.13
-0.09
0.04
-0.12
0.64
-0.54
0.27
0.57
-0.17
0.44
-0.32
0.40
-0.11
0.07
0.07
0.15
-0.09
0.02
0.03
0.04
0.21
0.02
-0.07
0.02
0.05
0.42
-0.44
0.24
0.57
-0.26
0.33
-0.35
0.37
-0.17
-0.04
0.02
0.12
-0.15
0.04
0.01
-0.07
0.03
-0.02
-0.04
0.00
-0.03
0.50
-0.44
0.27
-0.04
-0.02
-0.03
0.07
0.03
-0.02
0.05
0.01
-0.05
0.08
-0.07
-0.09
-0.03
0.16
0.37
0.10
0.07
0.10
-0.04
-0.01
0.04
-0.11
-0.15
0.05
-0.16
0.20
-0.08
-0.12
-0.02
0.13
-0.07
-0.09
-0.17
-0.11
-0.06
0.09
-0.08
-0.07
-0.02
-0.06
0.10
0.81
-0.12
-0.03
-0.01
-0.07
0.01
-0.03
0.03
0.03
0.21
-0.06
-0.07
-0.06
0.00
-0.01
-0.07
-0.07
-0.04
0.07
-0.03
-0.03
0.23
-0.10
-0.18
0.50
-0.19
0.06
-0.10
0.02
0.21
0.02
-0.14
-0.02
0.04
0.28
-0.01
-0.15
0.02
-0.09
0.17
-0.25
0.08
-0.13
0.66
-0.03
0.28
-0.20
0.35
-0.08
0.01
0.08
0.14
0.00
0.05
0.05
0.01
0.00
0.10
-0.12
0.02
0.24
0.44
-0.62
0.46
0.65
0.00
0.30
-0.25
0.25
-0.09
0.14
0.18
0.21
0.04
0.03
0.11
-0.04
0.12
-0.06
-0.12
0.08
0.25
0.51
-0.69
0.33
1.00
0.14
-0.04
0.01
-0.03
0.03
0.06
0.17
0.02
0.09
0.09
0.07
0.00
-0.03
0.13
-0.08
0.04
0.19
0.53
-0.71
0.32
0.14
1.00
-0.04
0.37
-0.21
0.31
0.25
0.11
-0.09
0.73
-0.07
0.26
-0.05
-0.02
-0.12
-0.04
0.35
0.47
-0.15
-0.23
0.30
-0.04
-0.04
1.00
-0.36
0.45
-0.26
0.02
0.18
0.01
-0.03
-0.11
0.30
0.29
0.09
-0.11
0.03
0.03
0.41
-0.41
0.05
0.03
0.01
0.37
-0.36
1.00
-0.24
0.22
0.04
-0.03
0.22
0.31
0.13
-0.07
-0.01
0.10
0.11
-0.03
0.20
-0.02
0.00
0.00
-0.01
-0.03
-0.21
0.45
-0.24
1.00
-0.07
-0.15
0.06
0.08
-0.10
0.16
0.12
0.06
0.08
0.09
-0.08
0.01
-0.10
0.08
-0.02
0.11
0.03
0.31
-0.26
0.22
-0.07
1.00
-0.03
0.03
-0.04
0.07
0.05
-0.01
-0.02
-0.01
-0.11
0.00
0.02
-0.03
0.20
-0.22
0.03
0.06
0.25
0.02
0.04
-0.15
-0.03
1.00
0.01
0.19
0.16
-0.05
0.19
-0.07
0.45
-0.09
-0.07
-0.01
0.08
0.04
-0.15
0.03
0.17
0.11
0.18
-0.03
0.06
0.03
0.01
1.00
0.06
0.03
0.04
0.10
0.26
0.02
-0.12
-0.08
0.00
0.34
-0.08
-0.22
0.08
0.02
-0.09
0.01
0.22
0.08
-0.04
0.19
0.06
1.00
-0.10
0.26
-0.08
0.09
0.43
0.12
-0.03
-0.05
-0.01
0.21
-0.24
0.11
0.09
0.73
-0.03
0.31
-0.10
0.07
0.16
0.03
-0.10
1.00
-0.07
0.12
-0.08
-0.01
0.04
-0.04
0.76
0.27
-0.05
-0.15
0.27
0.09
-0.07
-0.11
0.13
0.16
0.05
-0.05
0.04
0.26
-0.07
1.00
0.00
0.19
-0.06
0.08
-0.02
-0.04
-0.11
0.25
-0.21
-0.09
0.07
0.26
0.30
-0.07
0.12
-0.01
0.19
0.10
-0.08
0.12
0.00
1.00
0.14
-0.08
-0.10
-0.06
-0.01
0.25
-0.11
-0.16
-0.02
0.00
-0.05
0.29
-0.01
0.06
-0.02
-0.07
0.26
0.09
-0.08
0.19
0.14
1.00
0.00
-0.13
0.02
-0.05
0.12
-0.12
-0.09
-0.12
-0.03
-0.02
0.09
0.10
0.08
-0.01
0.45
0.02
0.43
-0.01
-0.06
-0.08
0.00
1.00
0.11
-0.02
0.03
-0.01
0.01
0.00
-0.05
0.13
-0.12
-0.11
0.11
0.09
-0.11
-0.09
-0.12
0.12
0.04
0.08
-0.10
-0.13
0.11
1.00
0.00
0.01
-0.22
0.14
0.03
0.09
-0.08
-0.04
0.03
-0.03
-0.08
0.00
-0.07
-0.08
-0.03
-0.04
-0.02
-0.06
0.02
-0.02
0.00
1.00
-0.03
0.00
-0.12
0.11
-0.08
0.04
0.35
0.03
0.20
0.01
0.02
-0.01
0.00
-0.05
0.76
-0.04
-0.01
-0.05
0.03
0.01
-0.03
1.00
0.09
0.00
-0.06
0.11
0.19
0.47
0.41
-0.02
-0.10
-0.03
0.08
0.34
-0.01
0.27
-0.11
0.25
0.12
-0.01
-0.22
0.00
0.09
1.00
-0.45
-0.29
0.23
0.53
-0.15
-0.41
0.00
0.08
0.20
0.04
-0.08
0.21
-0.05
0.25
-0.11
-0.12
0.01
0.14
-0.12
0.00
-0.45
1.00
-0.67
0.10
-0.71
-0.23
0.05
0.00
-0.02
-0.22
-0.15
-0.22
-0.24
-0.15
-0.21
-0.16
-0.09
0.00
0.03
0.11
-0.06
-0.29
-0.67
1.00
-0.26
0.32
0.30
0.03
-0.01
0.11
0.03
0.03
0.08
0.11
0.27
-0.09
-0.02
-0.12
-0.05
0.09
-0.08
0.11
0.23
0.10
-0.26
1.00
Pearson
min
Tab. 5.4
Spearman correlation matrix of analyzed parameters from all groundwater samples
Spearman min
pH
O2
ChSK
Li
Na
K
Ca
Mg
Sr
Fe
Mn
NH4
F
Cl
SO4
NO3
PO4 HCO3 SiO2 vCO2 aCO2
mineralizázia
1.00
pH
0.13
O2
-0.19
ChSKmn 0.63
Li
0.62
Na
0.84
K
0.44
Ca
0.71
Mg
0.80
Sr
0.67
Fe
0.01
Mn
-0.03
NH4
0.07
F
0.25
Cl
0.86
SO4
0.82
NO3
0.65
PO4
0.12
HCO3
0.68
SiO2
-0.26
vCO2
0.29
agr.CO2 -0.12
Cr
0.13
Cu
0.41
Zn
0.39
As
0.02
Cd
0.13
Se
0.38
Pb
0.16
Hg
0.04
Ba
-0.03
Al
-0.19
Sb
0.10
S1
0.52
S2
0.17
A2
-0.58
stupeň zneč.
0.34
0.13
1.00
0.01
0.27
0.21
0.10
0.35
-0.04
0.05
-0.03
0.07
-0.27
0.08
0.18
-0.04
0.03
0.05
0.25
0.22
-0.18
-0.40
0.03
0.19
0.15
-0.10
0.24
-0.12
0.08
0.05
-0.06
-0.33
0.21
0.21
0.26
-0.21
0.07
-0.14
-0.19
0.01
1.00
-0.26
-0.16
-0.21
-0.19
-0.14
-0.19
-0.14
-0.17
-0.25
-0.22
-0.10
-0.18
-0.11
0.05
-0.03
-0.29
0.23
-0.44
0.17
-0.01
-0.13
-0.33
-0.01
-0.02
0.01
-0.14
-0.16
0.03
-0.09
-0.05
-0.22
0.05
-0.02
-0.08
0.63
0.27
-0.26
1.00
0.45
0.55
0.57
0.25
0.43
0.25
-0.04
0.01
0.35
0.16
0.48
0.45
0.31
0.36
0.55
-0.12
0.20
0.04
0.03
0.54
0.18
0.20
-0.01
0.19
0.20
0.12
-0.20
-0.01
0.21
0.58
-0.16
-0.29
0.20
0.62
0.21
-0.16
0.45
1.00
0.46
0.61
0.20
0.39
0.15
0.15
-0.24
0.12
0.22
0.42
0.36
0.52
0.32
0.45
0.06
0.12
0.03
0.18
0.56
0.34
0.22
0.13
0.38
0.25
0.15
-0.09
-0.09
0.22
0.59
-0.12
-0.39
0.08
0.84
0.10
-0.21
0.55
0.46
1.00
0.27
0.56
0.69
0.62
-0.02
0.05
0.08
0.20
0.84
0.79
0.44
0.04
0.54
-0.29
0.23
-0.10
0.18
0.36
0.39
-0.02
0.08
0.26
0.15
0.00
-0.22
-0.17
0.15
0.64
0.12
-0.52
0.34
0.44
0.35
-0.19
0.57
0.61
0.27
1.00
-0.09
0.08
-0.14
0.13
0.05
0.21
0.24
0.16
0.11
0.25
0.59
0.52
0.01
0.00
0.10
-0.06
0.59
0.20
0.43
-0.08
0.34
0.23
0.09
-0.09
-0.08
0.24
0.70
-0.48
-0.09
0.18
0.71
-0.04
-0.14
0.25
0.20
0.56
-0.09
1.00
0.83
0.88
-0.03
-0.01
-0.13
0.08
0.78
0.79
0.53
-0.25
0.33
-0.39
0.32
-0.22
0.11
0.05
0.33
-0.21
0.16
0.14
-0.03
-0.04
0.12
-0.17
-0.08
-0.03
0.67
-0.50
0.20
0.80
0.05
-0.19
0.43
0.39
0.69
0.08
0.83
1.00
0.80
0.05
-0.01
-0.06
0.23
0.77
0.80
0.50
-0.21
0.55
-0.44
0.41
-0.20
0.13
0.14
0.27
-0.17
0.16
0.20
0.16
0.05
-0.01
-0.09
0.04
0.20
0.43
-0.44
0.17
0.67
-0.03
-0.14
0.25
0.15
0.62
-0.14
0.88
0.80
1.00
-0.10
0.03
-0.12
0.16
0.74
0.78
0.40
-0.33
0.36
-0.44
0.28
-0.29
0.10
0.00
0.27
-0.34
0.15
0.10
0.01
0.00
0.01
-0.08
-0.01
0.05
0.54
-0.40
0.17
0.01
0.07
-0.17
-0.04
0.15
-0.02
0.13
-0.03
0.05
-0.10
1.00
-0.07
0.00
0.11
-0.05
-0.09
0.08
0.11
0.06
-0.04
0.22
-0.01
0.05
0.00
-0.02
0.18
-0.04
-0.07
-0.05
0.23
0.13
0.11
0.10
0.05
-0.05
0.05
-0.02
-0.03
-0.27
-0.25
0.01
-0.24
0.05
0.05
-0.01
-0.01
0.03
-0.07
1.00
0.20
-0.06
0.06
0.00
-0.39
-0.28
0.14
-0.15
0.28
-0.17
-0.24
-0.15
0.01
-0.18
-0.09
-0.31
-0.14
-0.04
0.22
-0.08
-0.18
0.00
-0.20
0.26
0.45
0.07
0.08
-0.22
0.35
0.12
0.08
0.21
-0.13
-0.06
-0.12
0.00
0.20
1.00
0.04
0.04
-0.02
-0.04
0.10
0.12
0.03
0.06
0.09
0.08
0.18
0.09
-0.03
-0.13
-0.02
0.09
0.13
-0.12
0.07
0.02
0.24
-0.25
0.02
0.23
0.25
0.18
-0.10
0.16
0.22
0.20
0.24
0.08
0.23
0.16
0.11
-0.06
0.04
1.00
0.10
0.07
-0.02
-0.05
0.50
-0.22
0.12
-0.12
0.08
0.19
0.11
-0.19
0.01
0.05
0.18
0.02
-0.16
-0.01
-0.04
0.15
-0.23
0.14
-0.15
0.86
-0.04
-0.18
0.48
0.42
0.84
0.16
0.78
0.77
0.74
-0.05
0.06
0.04
0.10
1.00
0.84
0.54
-0.09
0.41
-0.24
0.33
-0.09
0.09
0.25
0.43
-0.06
0.20
0.21
0.09
-0.01
0.05
-0.20
0.02
0.38
0.43
-0.66
0.40
0.82
0.03
-0.11
0.45
0.36
0.79
0.11
0.79
0.80
0.78
-0.09
0.00
-0.02
0.07
0.84
1.00
0.55
-0.12
0.36
-0.31
0.21
-0.12
0.19
0.22
0.40
-0.10
0.15
0.26
0.06
-0.01
-0.12
-0.15
0.09
0.37
0.48
-0.68
0.33
0.65
0.05
0.05
0.31
0.52
0.44
0.25
0.53
0.50
0.40
0.08
-0.39
-0.04
-0.02
0.54
0.55
1.00
0.20
0.09
0.02
0.01
0.12
0.14
0.43
0.31
0.20
0.15
0.35
0.10
0.02
0.09
-0.12
0.14
0.29
0.45
-0.76
0.27
0.12
0.25
-0.03
0.36
0.32
0.04
0.59
-0.25
-0.21
-0.33
0.11
-0.28
0.10
-0.05
-0.09
-0.12
0.20
1.00
0.16
0.35
-0.17
0.27
-0.05
0.42
-0.05
0.65
-0.06
0.37
0.15
0.10
-0.09
0.06
0.28
0.45
-0.39
-0.05
0.02
0.68
0.22
-0.29
0.55
0.45
0.54
0.52
0.33
0.55
0.36
0.06
0.14
0.12
0.50
0.41
0.36
0.09
0.16
1.00
-0.38
0.37
-0.21
-0.04
0.29
0.15
-0.03
-0.04
0.29
0.22
0.09
-0.08
-0.09
0.06
0.47
-0.37
0.09
0.00
-0.26
-0.18
0.23
-0.12
0.06
-0.29
0.01
-0.39
-0.44
-0.44
-0.04
-0.15
0.03
-0.22
-0.24
-0.31
0.02
0.35
-0.38
1.00
-0.24
0.23
0.02
0.02
-0.08
0.25
-0.01
-0.08
-0.08
0.16
0.15
-0.04
0.10
-0.04
-0.13
0.01
0.07
0.29
-0.40
-0.44
0.20
0.12
0.23
0.00
0.32
0.41
0.28
0.22
0.28
0.06
0.12
0.33
0.21
0.01
-0.17
0.37
-0.24
1.00
-0.17
-0.21
0.00
0.20
-0.23
0.14
-0.01
0.16
0.16
0.17
-0.06
-0.25
-0.03
0.08
-0.01
0.10
-0.12
0.03
0.17
0.04
0.03
-0.10
0.10
-0.22
-0.20
-0.29
-0.01
-0.17
0.09
-0.12
-0.09
-0.12
0.12
0.27
-0.21
0.23
-0.17
1.00
0.01
0.14
-0.09
0.34
0.06
0.13
0.02
-0.02
-0.14
0.00
0.02
0.09
0.03
-0.23
0.07
Cr
Cu
Zn
As
Cd
Se
Pb
Hg
Ba
Al
Sb
S1
S2
A2
st.zn.
0.13
0.19
-0.01
0.03
0.18
0.18
-0.06
0.11
0.13
0.10
0.05
-0.24
0.08
0.08
0.09
0.19
0.14
-0.05
-0.04
0.02
-0.21
0.01
1.00
0.11
0.09
-0.02
-0.12
-0.04
-0.11
0.27
-0.18
0.01
0.04
0.11
0.12
-0.22
-0.03
0.41
0.15
-0.13
0.54
0.56
0.36
0.59
0.05
0.14
0.00
0.00
-0.15
0.18
0.19
0.25
0.22
0.43
0.42
0.29
0.02
0.00
0.14
0.11
1.00
0.31
0.33
0.00
0.28
0.13
0.10
-0.21
-0.11
0.20
0.60
-0.15
-0.34
0.05
0.39
-0.10
-0.33
0.18
0.34
0.39
0.20
0.33
0.27
0.27
-0.02
0.01
0.09
0.11
0.43
0.40
0.31
-0.05
0.15
-0.08
0.20
-0.09
0.09
0.31
1.00
-0.10
0.24
0.06
0.08
0.04
-0.04
-0.25
-0.03
0.32
0.27
-0.45
0.12
0.02
0.24
-0.01
0.20
0.22
-0.02
0.43
-0.21
-0.17
-0.34
0.18
-0.18
-0.03
-0.19
-0.06
-0.10
0.20
0.65
-0.03
0.25
-0.23
0.34
-0.02
0.33
-0.10
1.00
-0.20
0.24
-0.06
0.12
-0.02
0.10
0.39
0.33
-0.15
-0.14
0.17
0.13
-0.12
-0.02
-0.01
0.13
0.08
-0.08
0.16
0.16
0.15
-0.04
-0.09
-0.13
0.01
0.20
0.15
0.15
-0.06
-0.04
-0.01
0.14
0.06
-0.12
0.00
0.24
-0.20
1.00
0.13
0.25
-0.34
0.10
-0.09
-0.21
-0.09
0.24
-0.25
-0.05
0.38
0.08
0.01
0.19
0.38
0.26
0.34
0.14
0.20
0.10
-0.07
-0.31
-0.02
0.05
0.21
0.26
0.35
0.37
0.29
-0.08
-0.01
0.13
-0.04
0.28
0.06
0.24
0.13
1.00
0.23
-0.16
-0.16
-0.08
0.14
0.35
-0.05
-0.29
-0.06
0.16
0.05
-0.14
0.20
0.25
0.15
0.23
-0.03
0.16
0.01
-0.05
-0.14
0.09
0.18
0.09
0.06
0.10
0.15
0.22
-0.08
0.16
0.02
-0.11
0.13
0.08
-0.06
0.25
0.23
1.00
0.01
-0.17
0.05
-0.07
0.22
-0.09
-0.07
-0.03
0.04
-0.06
-0.16
0.12
0.15
0.00
0.09
-0.04
0.05
0.00
0.23
-0.04
0.13
0.02
-0.01
-0.01
0.02
0.10
0.09
0.16
0.16
-0.02
0.27
0.10
0.04
0.12
-0.34
-0.16
0.01
1.00
0.12
0.08
0.18
0.04
-0.06
0.03
-0.06
-0.03
-0.33
0.03
-0.20
-0.09
-0.22
-0.09
0.12
-0.01
0.01
0.13
0.22
-0.12
-0.16
0.05
-0.12
0.09
-0.09
-0.08
0.15
0.17
-0.14
-0.18
-0.21
-0.04
-0.02
0.10
-0.16
-0.17
0.12
1.00
-0.07
-0.13
-0.33
0.12
0.03
0.15
-0.19
0.21
-0.09
-0.01
-0.09
-0.17
-0.08
-0.17
-0.09
-0.08
0.11
-0.08
0.07
-0.01
-0.20
-0.15
-0.12
0.06
-0.09
-0.04
-0.06
0.00
0.01
-0.11
-0.25
0.10
-0.09
-0.08
0.05
0.08
-0.07
1.00
0.21
-0.09
-0.08
0.11
-0.17
0.10
0.21
-0.05
0.21
0.22
0.15
0.24
-0.08
0.04
-0.01
0.10
-0.18
0.02
-0.04
0.02
0.09
0.14
0.28
0.06
0.10
-0.25
0.02
0.04
0.20
-0.03
0.39
-0.21
0.14
-0.07
0.18
-0.13
0.21
1.00
0.30
-0.06
-0.13
0.04
0.52
0.26
-0.22
0.58
0.59
0.64
0.70
-0.03
0.20
0.05
0.05
0.00
0.24
0.15
0.38
0.37
0.29
0.45
0.47
-0.04
-0.03
0.09
0.11
0.60
0.32
0.33
-0.09
0.35
0.22
0.04
-0.33
-0.09
0.30
1.00
-0.39
-0.27
0.24
0.17
-0.21
0.05
-0.16
-0.12
0.12
-0.48
0.67
0.43
0.54
-0.05
-0.20
-0.25
-0.23
0.43
0.48
0.45
-0.39
-0.37
-0.13
0.08
0.03
0.12
-0.15
0.27
-0.15
0.24
-0.05
-0.09
-0.06
0.12
-0.08
-0.06
-0.39
1.00
-0.61
0.09
-0.58
0.07
-0.02
-0.29
-0.39
-0.52
-0.09
-0.50
-0.44
-0.40
0.05
0.26
0.02
0.14
-0.66
-0.68
-0.76
-0.05
0.09
0.01
-0.01
-0.23
-0.22
-0.34
-0.45
-0.14
-0.25
-0.29
-0.07
0.03
0.03
0.11
-0.13
-0.27
-0.61
1.00
-0.32
0.34
-0.14
-0.08
0.20
0.08
0.34
0.18
0.20
0.17
0.17
-0.02
0.45
0.23
-0.15
0.40
0.33
0.27
0.02
0.00
0.07
0.10
0.07
-0.03
0.05
0.12
0.17
-0.05
-0.06
-0.03
-0.06
0.15
-0.17
0.04
0.24
0.09
-0.32
1.00
Fig. 5.2
Adapted Piper diagram for groundwaters with fluvial dissolved solid contents
6. Characteristics of groundwater quality
Groundwater qualitative properties in the region reflect either natural character of the area
(basically its geological structure) or addition of elements and compounds due to anthropogenic
activities (secondary contamination). Taking into consideration the demands on water for human
consumption (Act of the Government of the SR no. 354/2006), the following natural factors
negatively affecting the groundwater quality were registered:
 impact of the rock environment,
 character of the source waters (rain water, surface water) – however they are also strongly
affected by anthropogenic activities.
In the groundwaters of the Quaternary sediments, manganese is often mobilized and in many
cases reaching the concentrations above the drinking water standard. Trace elements – toxic metals
are mobilized from the rock structure of the region only to limited extent. Considering the
precipitation, groundwater and surface water quality is strongly affected by its low pH values (acid
character) and by high concentrations of ammonium ions reaching the values above the drinking
water standard (0,5 mg.l-1).
Secondary (anthropogenic) factors affecting the groundwater quality are very common
practically in the whole investigated area. The man-made origin of groundwater chemical
composition forms a significant addition to the natural contribution. Anthropogenic contamination
of groundwaters is mostly produced by agricultural activities and production of waste waters.
Among other elements/compounds of the man-made origin, mostly high concentrations of nitrates,
chlorides, sulphates, manganese or specific organic group parameters (PAH, NEL) typically occur in
the contaminated groundwaters.
Overview of chemical parameters (except from trace elements), which don’t meet the
criteria of the Act of the Government of SR no. 354/2006 valid for drinking waters, is displayed in
tab. 6.1. Concentrations of nitrates coming from intense agricultural activities (almost 2/3 of the
samples) and values of CODmn (more than 44% of sampling sites) exceed the set up limit values
most frequently. In case of recommended characteristics, according to the Act of the Government of
SR no. 354/2006, low concentrations of dissolved oxygen (less than 5 mg.l-1) were documented in
almost 60% of the sampling sites. Moreover, high values (above recommended range) of water
hardness (Ca+Mg content higher than 5 mmol.l-1) were observed in almost 40% of the sampling
sites and high values of dissolved solids contents were measured (in more than 55% of the sampling
sites above the drinking water standard) in highly mineralized groundwaters. Generally a high
anthropogenic load in the area is also documented by above limit concentrations of chlorides
(26,6% cases), sulphates (20,7% cases) and phosphates (22,9% cases).
Tab. 6.1
Component
TDS
CODMn
NH4
NO2
NO3
Limit concentrations of selected chemical parameters following the Act of the
Government of the Slovak Republic No. 354/2006 on demand to water intended for
human consumption and exceedance of these limit concentrations at individual
sampling sites
Limit
concentration
(mg.l-1)
1000
3
0,5
0,1
50
parameter
pH
O2
Ca
Ca+Mg
Number of
exceedance
Number of
exceedance
Component
(%)
54,8
44,4
0
0
63,7
F
Cl
SO4
Mg
PO4
74
60
0
0
86
Recommended value
6,5-8,5
< 5 (<50%)
< 30 mg.l-1
1,1-5,0 mmol.l-1
Limit
concentration
(mg.l-1)
1,5
100
250
125
1
Number of sites out of range
8
80
1
54
Number of
exceedance
0
36
28
0
31
Number of
exceedance
(%)
0
26,6
20,7
0
22,9
Number of sites out of range (%)
5,9
59,2
0,74
39,2
Trace elements (their concentrations are usually below 1 mg.l-1) have achieved a very
specific position if groundwater quality assessment is concerned. Observation of trace elements in
groundwaters is very important due to their toxic properties at higher concentration levels. Most of
them can lead to weighty negative impact on water quality coupled with potential risk on health
statement of biota and human-beings. Occurrence of trace elements in drinking waters is strictly
limited in the Act of the Government of the SR no. 354/2006 (overloads of limit concentrations are
summarized in tab. 6.2).
In most cases, the distribution of trace elements in the investigated area corresponds with
natural conditions of the groundwater circulation, i.e. concentrations of trace elements are very low
and mostly below the limits of quantification. Concentrations of Cr, Cu, Cd, Pb, Hg, Ba and filtered
Al exceeding the limit values were observed in no case. Rarely, the concentrations exceeding the
limits were recorded in the following trace components: iron (three times), arsenic (four times),
antimony (one times). Multiply overloads of the limit concentrations were reported only for
manganese, aluminium, zinc and selenium. Their higher concentrations can indicate their
anthropogenic origin in groundwaters.
Tab. 6.2
Compound
Fe
Mn
Al
Al filtered
Cr
Cu
Zn
Limit concentrations of trace elements following the Act of the Government of the
Slovak Republic No. 354/2006 on demand to water intended for human consumption
and exceedance of these limit concentrations at individual sampling sites
Limit
concentration
(mg.l-1)
0,2
0,05
0,2
0,2
0,05
0,5
3
Number of
exceedance
3
65
10
0
0
0
10
Number of
exceedance
(%)
2,2
48,1
7,4
0
0
0
7,4
Compound
As
Cd
Se
Pb
Hg
Ba
Sb
Limit
concentration
(mg.l-1)
0,01
0,003
0,01
0,01
0,001
1
0,005
Number of
exceedance
4
0
16
0
0
0
1
Number of
exceedance
(%)
2,9
0
11,8
0
0
0
0,74
Considering manganese, the highest concentrations were documented mostly in the
groundwaters sampled from boreholes, where except from the natural conditions also the borehole
equipment can partly affect their higher contents. Comparing the observations in natural (noninfluenced) areas, the aluminium concentrations hovering between 0.2-0.5 mg.l-1 can be considered
as natural. However, due to the intensive anthropogenic load in the area, secondary addition of
aluminium to groundwater is expected as well. High concentrations of zinc and selenium likely
reflect agricultural activities in the region.
Contamination character of groundwaters is expressed via so-called the contamination index
Cd (Fig. 6.1). Contamination factor is calculated for each analysed groundwater as a sum of
contamination factors of individual analysed compounds exceeding the standard drinking water
value according to the Act no. 354/2006 (Backman et al., 1998):
n
C  C
d
i 1
fi
,
C
fi

C
C
Ai
 1 , where
Ni
Cd – level of sample contamination (contamination index),
Cfi – contamination factor for the i-th component,
CAi – analytical value of the i-th component,
CNi – normative value of the i-th component.
It can be stated that contamination index of groundwaters in the area reaches a very high
average value (8,54) which indicates and approves the above mentioned facts about intense
contamination of groundwaters practically in the whole region. The results presented in Fig. 6.1
show high values of contamination index predominantly in the southern part of the area.
Based on the results obtained within the project, the strong negative impact of anthropogenic
activities to groundwater qualitative properties in the area has been approved. Comparing the results
with the standard values according to the Act of the Government no. 354/2006, only groundwaters
of worsen D quality class and the worst H quality class were allocated. Spatial definition of
individual groundwater quality classes in square kilometres and percentages of the total area is
presented in Tab. 6.3.
Most of the area (about 81%) consists of groundwaters of the worst H quality class.
Combination of partly natural but mostly of anthropogenic factors (pollution coming from
agriculture, industry, municipal waste) forms the groundwater chemistry with significantly
deteriorated quality. Especially high concentrations (often above the drinking water standard) of
nitrates as well as phosphates, sulphates, chlorides, CODmn and others indicate the contamination in
groundwaters.
Groundwaters of D quality class were set in almost 20% of the area. These groundwaters
were delineated mostly in the Latorica preserve area with the low anthropogenic impact on their
quality. Groundwaters of the D quality class are characterized by high (above limit) values of the
following chemical components: manganese, chlorides, sulphates and dissolved solids.
Definition of groundwater quality classes at individual sampling sites is presented in Tab.
6.4. It is obvious, that the worst H quality class was defined for the most groundwaters (almost 40%
of sampling sites). Groundwaters of C and F quality classes were defined in 14.8% of cases, while
groundwaters of D quality class in 10.4% of cases.
Tab. 6.3
Spatial definition of groundwater quality classes
Quality class
A
D
H
Total
sqkm
0,5
78
339
417,5
%
0,1
18,7
81,2
100
Tab. 6.4
Presence of groundwater quality classes at individual sampling sites
Quality class
A
B
C
D
E
F
G
H
Total
Number of
sampling sites
5
5
20
14
8
20
11
52
135
Number of sampling sites
(%)
3,7
3,7
14,8
10,4
5,9
14,8
8,1
38,6
100
Fig. 6.1 Map of distribution of Contamination degree in groundwaters
7. Conclusion
The main objective of the report was to compile specific hydrogeochemical map of
Medzibodrožie region based on the results of groundwater chemical composition. Basic principles
of the map compilation were summarized in Rapant – Bodiš (2003) making use of a geological map
and information. Complete hydrogeochemical dataset used for the hydrogeochemical map
compilation represents 135 analyses of groundwaters from 135 sampling sites in total.
Generally two basic groundwater types are formed in the region. Those, the chemical
compositions of which closely coincide with the mineralogic-petrographic character of the
particular rock settings of their circulation, are qualified as groundwaters with petrogenous
dissolved solids contents. The second groundwater group, prevailing in the area, represents socalled fluvial waters of the main river sediments of the Latorica, Tisa and Bodrog rivers. Surface
waters characterized by temporal and spatial variability of dissolved solids contents are considered
as a main source of those groundwaters.
Chemical composition of petrogenous groundwaters is formed chiefly as a result of
dissolution of carbonates and hydrolytical decomposition of silicate minerals, in less extent as
a result of oxidation of sulphides, dissolution of gypsum or halite respectively, ion-exchange
reactions and biochemical processes.
Strong variability of values of total dissolved solids, evident in groundwaters, characterize a
complexity of hydrogeochemical conditions of groundwater chemistry formation. Values of total
dissolved solids in groundwaters of shallow regime of the first aquifer mostly range between 4001600 mg.l-1, exceptionally reaching more than 2000 mg.l-1.
Unpolluted natural groundwaters of the Latorica, Uh, Medzibodrožie and Tisa fluvial
sediments (SE part of the Východoslovenská nížina lowland) are predominantly of Ca-Mg-HCO3(SO4) type with the contents of dissolved solids ranging between 500-800 mg.l-1. Because of the
prevailing water-rock interactions (but strongly affected by man-made activities), the main
significant A2 and the less significant Ca-HCO3, and Ca-Mg-HCO3 types of chemical content
dominate (almost 40% samples) the groundwater of the first aquifer. In more than 1/3 of
groundwater samples, a higher contribution of S2(SO4) component (above 25 equivalent %) was
observed. Anthropogenic influence on groundwater chemical composition is indicated by abundant
presence of groundwaters with the different transient and mixed groundwater chemical types.
Different contribution of chemical compounds Na-K-Ca-Mg-HCO3-SO4-NO3-Cl is characteristic
for those waters. Contents of total dissolved solids reach values of about 1000-1500 mg.l-1 (with an
average value of 1128.6 mg.l-1 for the whole dataset).
Groundwater qualitative properties in the region reflects either natural character of the area
(basically its geological structure) or addition of elements and compounds due to anthropogenic
activities (secondary contamination). Anthropogenic contamination of groundwaters is mostly
produced by agricultural activities and production of waste waters. Concentrations of nitrates
coming from intense agricultural activities (almost 2/3 of the samples) and values of CODmn (more
than 44% of sampling sites) exceed the set up limit values most frequently. Low concentrations of
dissolved oxygen (less than 5 mg.l-1) were documented in almost 60% of the sampling sites.
Moreover, high values of water hardness (Ca+Mg content higher than 5 mmol.l-1) were observed in
almost 40% of the sampling sites and high values of dissolved solids contents were measured in
highly mineralized groundwaters (in more than 55% of the sampling sites above the drinking water
standard). Generally, a high anthropogenic load in the area is also documented by above limit
concentrations of chlorides (26.6% cases), sulphates (20.7% cases) and phosphates (22.9% cases).
In most cases, the distribution of trace elements in the investigated area corresponds with
natural conditions of the groundwater circulation, i.e. concentrations of trace elements are very low
and mostly below the limits of quantification. Multiply overloads of the limit concentrations were
reported only for manganese, aluminium, zinc and selenium. Their higher concentrations can
indicate their anthropogenic origin in groundwaters.
Most of the area (about 81%) consists of groundwaters of the worst H quality class.
Combination of partly natural but mostly of anthropogenic factors forms the groundwater chemistry
with significantly deteriorated quality. Groundwaters of D quality class were set in almost 20% of
the area. These groundwaters were delineated mostly in the Latorica preserve area with the low
anthropogenic impact to their quality. Groundwaters of the D quality class are characterized by high
(above limit) values of the following chemical components: manganese, chlorides, sulphates and
dissolved solids.
8. Literature
ACT
OF THE
GOVERNMENT
OF THE
SLOVAK REPUBLIC from 10 May 2006 on demand to water
intended for human consumption and quality control of water intended for human consumption (in
Slovak). Law Collection No. 354. p. 2524-2542.
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investigation (in Slovak). Manuscript – archive of ŠGÚDŠ Bratislava. 52 p.
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