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HYDROCHEMICAL CHARACTERISTICS OF SOME LITHOLOGICALY DIFFERENT KARST MASSIFS OF ALBANIA

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The chemistry of 25 springs located at four karst areas of Albania with different lithology shows a very clear relation of the karst water quality to the lithology of rocks. Most indicative parameters characterizing the chemistry of karst springs result: water conductivity, total hardness, ionic ratios rCa/rMg, rSO 4 /rMg, CO 2 pressure and the indexes of calcite (Si c) and dolomite saturation (Si d). Very useful for the attachment of the chemistry to the special lithologic units results the graphic of rCa/rMg versus rCa/rMg, combined with SO 4 content, as well as the graphic of indexes of calcite saturation versus the indexes of dolomite saturation. The water quality parameters are used also to characterize the karst flow system of carbonate springs. The Blue Eye Spring, the biggest spring of Albania, which average discharge is about 18.5 m³/s has a diffuse-flow feeder-system. Key words: Karst water chemistry, index of calcite saturation, index of dolomite saturation, CO 2 pressure, kasrt flow system.
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499
HYDROCHEMICAL CHARACTERISTICS OF SOME
LITHOLOGICALY DIFFERENT KARST MASSIFS OF ALBANIA
Romeo Eftimi
ITA Consult, Tirana, Albania, eftimi@sanx.net
Abstract: The chemistry of 25 springs located at four karst areas of Albania with different
lithology shows a very clear relation of the karst water quality to the lithology of rocks. Most
indicative parameters characterizing the chemistry of karst springs result: water conductivity,
total hardness, ionic ratios rCa/rMg, rSO4/rMg, CO2 pressure and the indexes of calcite (Sic)
and dolomite saturation (Sid). Very useful for the attachment of the chemistry to the special
lithologic units results the graphic of rCa/rMg versus rCa/rMg, combined with SO4 content, as
well as the graphic of indexes of calcite saturation versus the indexes of dolomite saturation.
The water quality parameters are used also to characterize the karst flow system of carbonate
springs. The Blue Eye Spring, the biggest spring of Albania, which average discharge is about
18.5 m³/s has a diffuse-flow feedersystem.
Key words: Karst water chemistry, index of calcite saturation, index of dolomite saturation,
CO2 pressure, kasrt flow system.
INTRODUCTION
About one-fourth of Albania’s land surface is karstified and about two-third of the
groundwater resources of the country are karstic ones. This study was focused on four
karst areas with different lithology; pure limestone, mainly dolomite, limestone and
dolomite and limestone with gypsum. The main objectives of this investigation were
the same as those pointed out by Back and Zöetl (1975) for the geochemical studies:
to determine the stratigraphic and lithologic distribution of the chemical water type, to
determine the quality suitability of karst water and to understand the physics of the
karst systems.
Description of the study areas
The studied karst areas are situated in the central and in the southern part of Albania
(Fig. 1). Table 1 gives the main geological and hydrogeological data of the
investigated karst massifs. Morphologically the investigated karst massifs represent
high mountains of 1600 to more than 2000 m a.m.s.l., which dominate on the
surrounding low elevation eroded flysch areas. The sinkholes and karst poles are a
very common phenomenon on Mali me Gropa and Tomori massifs; they form karst
plateaus which appear as the main recharge area of the major springs. At the
remaining investigated karst massifs, while the sinkholes practically are missing, some
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500
big karst caves are developed. The groundwater
flow direction is controlled mainly by the
hydraulic slope; sometimes the ground water
cross faults, folds and stratification beds.
Method of study
Physical and chemical data were collected at 25
mostly big springs. A total of 84 water samples
from these springs were analyzed for major
dissolved components. The frequency of
sampling varied; only two springs, the Blue Eye
and Pellumbas are sampled more systematically.
At each sample site was measured the water
temperature, ph and electrical conductivity (EC),
while the chemical parameters are determined in
the laboratory. Chemical analyses were
conducted within 4 days of sampling. From the
results of the chemical analyses ionic strength I,
calcite saturation index Sic, dolomite saturation
index Sid, the equilibrium of carbon dioxide
Fig. 1. Location of studied karst pressure PCO2, rCa/rMg and rCa+rMg, (r denotes
massifs: 1. Dajti; 2. Mali me Gropa the value is in e.p.m.) are calculated.
3. Tomori; 4. Mali i Gjere
Table 1. Main geological and hydrogeological data of the investigated karst massifs.
Nr.
Name of
the area
Lithology
Surface
km²
Yearly
precipitation
mm
Yearly
infiltration
mm
Main springs and the
average discharge
l/s
1
Dajti
Cretaceous dolomites
and less Eocene
limestone
80
1800
700
Pellumbas, 500
Buvilla, 390
Gryka e Buvilles, 30
Gjorm, 15
2
Mali me
Gropa
Triassic pure
limestone
165
2100
1150
Selita, 510
Shemria, 1100
Guri Bardhe, 700
3
Tomori
Cretaceous dolomite
and Eocene limestone
145
1365
650
Kerpica, 725
Bogova, 1350
Guaku, 1500
4
Mali Gjere
Mesozoic and
Paleogene limestone
with siliceous rocks
340
2260
1175
Blue Eye, 18.500
Viroi, 0-35.000
Vrisi, 90
Kardhikaqi, 250
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501
Sic and Sid are defined (Garrels and Christ, 1965, Thrailkill, 1976) as
Sic = (Ca2+). (CO32-) / Kc (1)
Sid = (Ca2+). (Mg2+). (CO32-)2 / Kd (2)
PCO2 = H2CO3 / KCO2
(3)
Where the brackets indicate activities of the ions; Kc, Kd and KCO2 are the respective
equilibrium constants of calcite dolomite and of carbon dioxide. Ionic strength (I) is
then calculated. Once I is known, the activity of ions Ca2+, Mg2+ and CO32- are
calculated using the Debye-Hückel equation (Garrels and Christ, 1965). The values of
the equilibrium constants used in this study are those given by Langmuir (1971),
Thrailkill (1972, 1976), Drever (1983) and others. The most important uncertainty
among measured values is in the pH. The total uncertainty in calculated values of Sic
and Sid is about ±0.15 units. We therefore assume that all values of indices within
±0.15 units of zero are saturated with respect to the carbonate in question.
Results and discussion
Hydrogeological data and chemical parameters and computed Sic and Sid and
equilibrium CO2 pressures values for the spring waters are generalized in Table 2 and
in the graphics of rCa/rMg versus rCa+rMg (Fig. 2) and of Sic versus Sid (Fig. 3).
Essential differences in chemistry exist between spring waters of different karst
massifs.
The spring waters of pure limestone of Mali me Gropa massif have low hardness, low
SO42- concentrations, and therefore also a low EC. In these waters, the ratio rCa/rMg
has high value, and in opposite of this the ratio rSO4/rMg has lower values. Similar
characteristics have also the spring waters of Tomori massif where the dominant rocks
are also the limestone.
Dolomite waters of Dajti massif are hard; they have relative high SO42- concentrations,
and high EC. The sulfate may come from the oxidation of the trace pyrite and
marcasite and of trace gypsum, which are present in dolomites of Dajti massif.
The water of Blue Eye spring in Mali Gjere massif is hard; the concentration of SO42-
is about 135 mg/l and EC is relatively high. The spring water is saturated with respect
to calcite and is near saturated with respect to dolomite. The main SO42- source for the
Blue Eye spring water seems to be the sulfate waters of nearby Drinos Valley that
recharge this spring. This contributes also to the increase of rSO4/rMg ratio of Blue
Eye spring water up to 5.4.
It is already known that rCa/rMg ratio in groundwater has a clear geochemical
implication; their values are usually lower in dolomite and higher in limestone
(Langmuir, 1971, Zötel, 1974). Zojer and Stichler (1988) have used the graphic of
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502
rCa/rMg versus rCa+rMg to attach hydrochemically differing waters to special
lithologic unites. The same is demonstrated in Fig. 2.
Table 2.Chemical data of the investigated karst springs; the numbers in the upper line show
the range and the number in the lower line shows the average value
Unity
Karst massifs
Dajti
Mali me
Gropa
Tomori
Mali Gjere
Dolomite
Limestone
Limestone
and less
dolomite
Limestone with
gypsum
15
5
7
Blue Eye Spring
20
15
8
35
HCO3-SO4-
Mg
HCO3 Ca
HCO3 Ca
SO4 Ca
° C
11.7 18.8
14.4
5.8 8.1
6.6
8.5 11.5
9.4
12.2 12.4
12.3
7.20 - 7.70
7.45
7.42 - -7.88
7.60
7.43 8.72
7.98
7.60 7.67
7.64
mg/l
10.6 309.0
83.0
5.4 12.4
8.2
5.8 26.3
10.6
118.6 135.7
131.1
μS/cm
347 863
542
145 222
207
224 391
271
535 594
574
mg/l
230 682
355
109 153
138
135 234
168
370 399
390
mg/eqv/
l
3.86 9 56
5.5
1.47 2.77
2.2
2.40 4.11
2.9
5.57 5.94
5.80
1.2 3.4
2.1
7.2 13.8
11.8
2.4 9.0
5.6
4.9 5.7
5.4
1.6 11 9
0.95
0.6 2.0
1.1
0.5 1.7
0.9
5.1 6.6
5.8
10xatm
-1.92 - -2.41
-2.1
-2.38 - -2.81
-2.6
-2.32 - -3.06
-2.80
-2.53 - - 3.28
-2.40
0.37 - -0.08
0.09
-0.46 - -0.04
-0.29
-0.28 - -0.09
0.10
-0.26 - -0.29
+2.28
-0.26 - -0.125
-0.07
-0.68 - -1.0
-0.90
-0.65 - -0.04
-0.20
-0.13 - -0.09
-0.11
For the investigated dolomite and limestone waters there exists an indirect correlation
between the rCa/rMg ratios and the sums of rCa+rMg, while the sulfate waters are
“displaced” from the “correlation” curve. The log PCO2 in the atmosphere is about -3.5
(Garrels and Christ, 1965) but the investigated spring waters contain in average an
order of magnitude more CO2 than they would if they were in equilibrium with the
atmosphere.
Water Resources & Environmental Problems in Karst - CVIJIĆ 2005
503
Fig. 2. investigated karst springs g. 2.
rCa/rMg versus rCa+rMg for the
Fig. 3. Sic versus Sid for the investigated
karst springs
The CO2 source is the humus material at recharge areas of springs where the
infiltration of the precipitation occurs. The introduction of CO2 into the water allows
solution of the carbonate rocks.
The data indicate that although most of limestone springs are undersaturated with
respect to calcite and dolomite, the amount of undersaturation with respect to dolomite
is much greater than that with respect to calcite (Fig. 3). This is explained with the
higher solution kinetics of calcite in comparison with dolomite (Thrailkill, 1977,
Appelo and Postma, 1999). Less saturated with respect to both, calcite and dolomite
are the spring waters of Mali me Gropa massif dominated by highly karstified pure
limestone. The dolomite spring waters of Dajti massif are saturated or nearly saturated
with respect to calcite and some of the spring waters are saturated with respect to
dolomite. The sulfate waters of the big Blue Eye spring results saturated with respect
to calcite and nearly saturated with respect to dolomite (Fig. 3).
Characterizing the physical aspect of karst aquifers
There are at least two end member types of the groundwater flow in karst aquifers:
conduit flow and diffuse flow. The variation of the physical and chemical
characteristics of the springs could be used to characterize physical behavior of the
karst aquifers (Shuster and White, 1971, Jacobson and Langmuir, 1974), but this could
be done estimating also the limitations (Scanlon and Thrailkill, 1987). Most valuable
arameters to be applied for this purpose seem to be the temperature, the hardness and
electrical conductivity. The coefficient of variation CV %, which equals 100 times
Water Resources & Environmental Problems in Karst - CVIJIĆ 2005
504
Table 3. Coefficient of variation for the springs Pellumbas and Blue Eye
Variable
Conduit type*
Diffusive type*
Spring
Pellumbas
Blue Eye
Temperature
1.4
26.9
4.2
0.6
Total hardness
3.6-4.8
18.6-26.0
13.4
7.0
EC μ
<10
10-20
7.2
5.0
* Shuster and White (1971) and Jacobson and Langmuir (1974)
the standard deviation divided by the mean, may describe the changes in water
chemistry. The coefficients of variation result grater for the conduit flow springs and
least for diffuse flow springs. Table 3 shows coefficients of variation for some
variables measured in Pellumbas and Blue Eye spring compared with some literature
data. Coefficients of variation of temperature, total hardness and EC suggest that both
springs are diffuse flow springs. The evaluation of all field hydrogeological evidences
supports the same conclusion.
Conclusions
The main factors controlling the formation of chemical composition of the
investigated karst massifs are their lithology, the solution of carbonates by the
introduction of CO2 into the water and the calcite and dolomite saturation conditions.
References
Appelo CAJ, Postma D, 1999: Geochemistry, groundwater and pollution, A.A. Balkema
Back W, Zötl J, 1975: Application of geochemical principles, isotopic methodology and
artificial tracers to karst hydrology. Hydrogeology of Karstic Terrains, IAH.
Drever II, 1983: The geochemistry of natural waters, Prentice Hall, Harper and Row R.
Eftimi R, 1998: Hydrochemistry of Dajti massif (in Albania)., Stud. Gjeofraf, 11, pp 60-64.
Eftimi R, Amataj S, & Zoto J, 2007: GW circulation in two carbonate aquifers of Albania;
Selected Papers on Hydrogeology 11,Taylor & Francis 2007, London p. 199-211.
Garrels RM, Cheery I A, 1965: Solution, minerals and equilibria, New York, Harper and Row.
Jacobson RL, Langmuir D, 1974: Controls on the quality variations of some carbonate spring
water. J. Hydrol., 23, pp 247-265
Langmuir D, 1971: The geochemistry of some carbonate ground waters of Central
Pennsylvania, Geochem., Cosmocchim., Acta 35, pp 1023-1045
Langmuir D, 1986: Physical and chemical characteristics of carbonate water. In: Guide to the
hydrology of carbonate rocks, UNESCO, pp 69-104
Scanlon BR, Thrailkill J, 1987: Chemical similarities among physically distinct springs type in
a karst terrain. J. Hydrolo., 89, pp 259-279
Shuster ET, White WB, 1971: Seasonal fluctuations in the chemistry of limestone springs: a
possible mean for characterizing carbonate aquifers, J. Hydrol., 14, pp 93-128
Thrailkill J, 1976: Carbonate equilibria in karst water. In: Karst hydrology and water resources.
Proceed. Of US-Yugoslavian Symp. Dubrovnik, pp 745 766
Thrailkill J, 1977: Relative solubilities of limestone and dolomite. Karst Hydrology. AIH
Memoirs, vol.XII, pp
Zojer H, Stichler BR, 1988: Groundwater characteristics and problems in carbonate aquifers,
IAEA-AG-329.2/8, pp 159-171.
... Karstic water has significant differences in physical-chemical characteristics. A study of 33 springs in five karst areas showed a clear relation of karst water quality to the lithology karst rocks (Eftimi 1998(Eftimi , 2005(Eftimi , 2017. Table 1 shows some indicative parameters characterizing the chemistry of karst springs and computed Sic and Sid and equilibrium CO 2 pressures values, while Fig. 6a and 6b shows the graphics of rCa/rMg versus rCa+rMg (Fig. 6a) and of Sic versus Sid (Fig. 6b). ...
... The dolomite waters of Dajti massif are hard (5-14 mlg/ eqv/l); the EC reaches 550 µS/cm and SO4 2− concentrations vary about 80 ml/l, coming probably from the oxidation of the trace pyrite and marcasite and gypsum present in dolomites of the investigated massif (Hem 1985;Eftimi 2005); the ratio rCa/rMg varies about 6-11. ...
... Most valuable parameters to be applied for this purpose seem to be the temperature, the hardness, and electrical conductivity, but saturation indexes of calcite (Sic) and dolomite (Sid) and partial pressure values of CO 2 (logPCO 2 ) are evaluated similarly to the discharge variation, also (Shuster and White 1971;Jacobson and Langmuir 1974;Eftimi 2005;Eftimi and Benderev, 2007b;Banzato et al. 2011;Abboud 2016). According to White (2010), the springs with highly undersaturated water drain open conduit systems (White 2010). ...
... Karstic water has significant differences in physical-chemical characteristics. A study of 33 springs in five karst areas showed a clear relation of karst water quality to the lithology karst rocks (Eftimi 1998(Eftimi , 2005(Eftimi , 2017. Table 1 shows some indicative parameters characterizing the chemistry of karst springs and computed Sic and Sid and equilibrium CO 2 pressures values, while Fig. 6a and 6b shows the graphics of rCa/rMg versus rCa+rMg (Fig. 6a) and of Sic versus Sid (Fig. 6b). ...
... The dolomite waters of Dajti massif are hard (5-14 mlg/ eqv/l); the EC reaches 550 µS/cm and SO4 2− concentrations vary about 80 ml/l, coming probably from the oxidation of the trace pyrite and marcasite and gypsum present in dolomites of the investigated massif (Hem 1985;Eftimi 2005); the ratio rCa/rMg varies about 6-11. ...
... Most valuable parameters to be applied for this purpose seem to be the temperature, the hardness, and electrical conductivity, but saturation indexes of calcite (Sic) and dolomite (Sid) and partial pressure values of CO 2 (logPCO 2 ) are evaluated similarly to the discharge variation, also (Shuster and White 1971;Jacobson and Langmuir 1974;Eftimi 2005;Eftimi and Benderev, 2007b;Banzato et al. 2011;Abboud 2016). According to White (2010), the springs with highly undersaturated water drain open conduit systems (White 2010). ...
... Karstic water has significant differences in physical-chemical characteristics. A study of 33 springs in five karst areas showed a clear relation of karst water quality to the lithology karst rocks (Eftimi 1998(Eftimi , 2005(Eftimi , 2017. Table 1 shows some indicative parameters characterizing the chemistry of karst springs and computed Sic and Sid and equilibrium CO 2 pressures values, while Fig. 6a and 6b shows the graphics of rCa/rMg versus rCa+rMg (Fig. 6a) and of Sic versus Sid (Fig. 6b). ...
... The dolomite waters of Dajti massif are hard (5-14 mlg/ eqv/l); the EC reaches 550 µS/cm and SO4 2− concentrations vary about 80 ml/l, coming probably from the oxidation of the trace pyrite and marcasite and gypsum present in dolomites of the investigated massif (Hem 1985;Eftimi 2005); the ratio rCa/rMg varies about 6-11. ...
... Most valuable parameters to be applied for this purpose seem to be the temperature, the hardness, and electrical conductivity, but saturation indexes of calcite (Sic) and dolomite (Sid) and partial pressure values of CO 2 (logPCO 2 ) are evaluated similarly to the discharge variation, also (Shuster and White 1971;Jacobson and Langmuir 1974;Eftimi 2005;Eftimi and Benderev, 2007b;Banzato et al. 2011;Abboud 2016). According to White (2010), the springs with highly undersaturated water drain open conduit systems (White 2010). ...
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... Karst water differs significantly in physic-chemical characteristics. A study of 25 springs in four karst areas of Albania with different lithology showed a very clear relation of karst water quality to the lithology concerned (Eftimi 1998(Eftimi , 2005. The most indicative parameters characterizing the chemistry of karst springs are water conductivity and temperature, total hardness, r/Ca/rMg, rSO 4 /rMg ionic ratios, CO 2 pressure and saturation indexes with calcite (SIc) and dolomite (SId). ...
... The variation in the physical and chemical properties of the springs is used to characterize the physical behaviour of karst aquifers (Shuster et al. 1971, Jacobson et al. 1974). The Blue Eye Spring is mainly a conduit flow spring, while the Pellumbas Spring, issuing from dolomites, is a diffuse flow spring (Eftimi 1998(Eftimi , 2005. ...
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This paper is focused on brackish springs of Albania, which temperature is usually lower than the mean air temperature of spring's issuing area. The total dissolved solids of the springs is more than 1000 mg/l, they are not drinkable, and rarely are used for balnoeological purposes. The groundwater of the alluvial aquifers of Albania, particularly those of Preadriatic Lowland, in wide areas are brackish, but they are not object of this paper. The brackish springs of Albania are mainly karst springs, which could be clasified into two groups: a springs originating in salty rocks, mainly gypsum, and b coastal and submurine springs. The hydrochemical facie of the springs of the first group is usually of Ca-SO4 somtimes with increased concentration of Cl-Na, while this of the second group usually is Cl-Na. In Fig. 1 are shown the bigest brackish springs of Albania, while in Fig. 13 are shown the hydrochemical correlations of the spring, while resulats of some chemical analyses of the springs are summarised in Table 2, page 193. Përmbledhje Ky studim përqëndrohet ne burimet e kripur (të cilët shpesh quhen edhe "të mjelmët), por që janë të ftohtë, pra kanë zakonisht temperatrurë të përafërt me temperatura mesatstare vjetore të ajrit të zonës ku ato dalin. Këto burime kanë mbetje të thatë më të madhe se 1000 mg/l, ato janë ujëra të pa pijshme dhe zakonisht nuk përdoren as për qëllime kurative. Në shtresat ujëmbajtëse të cekëta, kryesisht që lidhen me depozitimet aluviale kuaternare ka gjithashtu ujëra të kripura të cilat nuk drenohen në formë burimesh, por ato nuk do jenë objekt i përshkrimit tonë. Burimet e kripura të Shqipërisë lidhen kryesisht me dy tipe të ndryshém shkëmbinshj karstikë: a burime që lidhen me depozitimet e halogjenëve, kryesisht gjipse, anhidride dhe kripëra, dhe b burime bregdetarë. Në pikpamje hidrokimike burimet e grupit të parë janë zakonisht të facies Ca-SO4, ndonjëhrëme përmabajtje të rritur të Cl-Na, kurse burimet e grupit të dytë janë té facies Cl-Na. Në Fig. 1 jepet përhapja e burimeve të kripura të Shqipërisë, kurse në Tabela 1 jepen rezultatet e analizave kimike të disa prej tyre. Hyrje Shtresat ujëmbajtëse karstike janë ndër më të pasurat në shkallë botërore (Bakalowicz 2005, Stevanović 2019, Goldscheider 2020) dhe padyshim janë shtresat ujëmbajtëse më të pasura të Shqipërisë (Eftimi 2020). Tek ne shtresat ujëmbajtëse karstike të përfaqësuara nga shkëmbinj karbonatikë, kryesisht gëlqerorë dhe dolomite, zënë rreth 6490 km 2 , dhe rreth 260 km 2 e zënë evaporitet, kryesisht gjipset. Për shkak të struktuës hidraulike të veçantë, shtresat ujëmbajtëse karstike manifestojnë luhatje shumë të ndjeshme cilësive të tyre të cilat lidhen me ndryshimet hidrometereologjike si luhatja e nivelit në shtresë, shpejtësia e lëvizjes në sistemin ujëpërçues, prurjet e burimeve dhe kimizmi i ujit (Hartman etj. 2014). Përveç kësaj, struktura e veçantë hidraulike i bën shtresat ujëmbajtëse karsitke veçanërisht të ndjeshme kundrejt ndotjes. Megjithatë burimet karstikë përdoren gjërësisht për furnizimin me ujë të popullsisë në botë (Stevanović 2015), duke përfshirë Evropën Jugë-Lindore (Stevanović & Eftimi 2010) dhe pa dyshim në Shqipëri ku ujërat karstike përdoren për furnizimin me ujë të rreth 80% tć popullsisë (Eftimi 2020). Përdorimi i burimeve karstikë si rezerva për furnizimin me ujë të popullsisë, kërkon vlerësimin e tyre të thelluar sasior dhe cilësor gjë që ndihmon edhe në karakterizimin regjional të rezervave të ujërave karstike nëpërgjithësi. Një studim mbi cilësinë e burimeve karstikë të Shqipërisë ka treguar se mjaft prej tyre janë të kripur (Eftimi 2005, 2010, 2011, 2020) dhe ky studim përqëndrohet pikërisht tek këto burime. Burime të kripura dhe të ftohta, ose shkurt burime të kripura, do quajmë ato të cilat kanë mbetje të thatë më të madhe se 1000 mg/l dhe temperatura e ujit është afërsisht e barabartë me
... In a study of some karst springs of Albania with diffuse recharge, the variation of different hydrogeological components like flow rate, temperature and electrical conductivity enable one to classify the karst aquifers into conduit and diffuse flow aquifers (Eftimi 2005). The classification of karst aquifer systems with a diffuse recharge, based on the variation of hydrochemical components, becomes much more realistic if the classification is validated also by the results of hydrograph analysis, as is demonstrated in the present study. ...
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The assessment of groundwater vulnerability/sensitivity to pollution in karstic aquifers usually concentrates on recognition of fast-flow (conduit flow) and slow-flow (diffuse flow) components or intermediate regimes and their ratio in the total discharged volume. Analysis of master recession curves and correlation between physical characteristics of springs and temporal variations in spring water chemistry were applied to two major karst springs of Albania: Selita Spring (mean discharge 510 L s⁻¹), exploited for Tirana water supply, and Blue Eye Spring (mean discharge 18,182 L s⁻¹), used for electric power generation. These springs are recharged by precipitation in two very different karst areas with respect to their karstification degree, which influences also groundwater circulation patterns within karstic aquifers. Different regional groundwater flow types are subsequently reflected in the different spring hydrographs and in the temporal hydrochemical variations. Based on the spring master recession curves, Selita Spring is characterised as a conduit spring where the fast-flow component represents the majority of groundwater flow, and its catchment area should be linked with a high degree of sensitivity to pollution. On the other hand, in the discharge regime of Blue Eye Spring, the slow-flow component dominates, and although having a discharge of one order of magnitude bigger, this is a diffuse-flow spring and its catchment area should have lower sensitivity to potential pollution. The same results were also confirmed by statistical treatment of the temporal variations in spring water chemistry and evidence of surface karst phenomena in their recharge areas.
... Many chemical analyses performed in the past confirmed the good quality of the Uji i Ftohtë waters. Based on non-systematic water quality monitoring, the main chemical parameters measured at drainage tunnels, are as follows: conductivity 400-760 lS/cm at 25 °C, TDS 250-540 mg/l, Cl 20-150 mg/l, SO 4 35-50 mg/l, Na 20-90 mg/l, 50-60 mg/l, NO 3 1-5 mg/l, NO 2 is below detection limit, pH 7.2-7.7; the hydrochemical type is HCO 3 -Ca-Mg (Eftimi 2005). A recent survey of this area stated that ''there is neither evidence of contamination nor relevant effects of sea water intrusion'' (Polemio et al. 2011), but does not deal with the water bacteriological situation. ...
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Albania is situated in the western part of the Balkan Peninsula, on the eastern coast of the Adriatic and the Ionian Sea. The karst landscape in Albania covers about 6750 km2, approximately 24 % of the Albanian territory. There are 25 karst regions in the country, 23 in carbonate rocks and 2 in evaporites. The total renewable karst water resources are estimated about 227 m3/s, representing 80 % of the groundwater resources of Albania. About 70 % of the population of the cities, including also part of the capital Tirana, obtains the water from karst springs. However, the negative human impacts often are threatening the karst groundwater resources of Albania. Several bad experiences in Albania have demonstrated that the main human negative impacts on karst water are related to: (a) urbanised areas, (b) agriculture activities, and (c) quarrying activities. Understanding the vital importance of karst waters and the necessity for intensive scientific investigations and monitoring, to evidence their high vulnerability, are still at a low level in Albania.
... It is already known that rCa 2+ /rMg 2+ ratio in groundwater has a clear geochemical implication; their values are usually lower in dolomite and higher in limestone (Langmuir, 1971;Zötl, 1974). The mean rCa 2+ /rMg 2+ ratio for some springs in pure limestone of Albania is 11.8 and for some dolomite springs is 2.1 (Eftimi, 2005). The rCa 2+ /rMg 2+ ratio for Iskrets spring is 3.3, which suggests that the water moves in limestone rich with dolomite. ...
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The paper describes the hydrochemistry of Iskrets Spring, which is one of the largest karst springs of Bul- garia. The spring's water has a composition expressed in equivalent units for cations: Ca2+ > Mg2+ > (Na++K+) and for anions: HCO3— > SO42— > NO3— > Cl—. Calcium and bicarbonate account present approximately 75% of the ions. The correlations between the concentrations of Ca2+ and Mg2+ to HCO3— are strong. The rCa2+/rMg2+ ratio for Iskrets Spring is 3.3, which suggests that the water moves in limestone and dolomite. The main ions Ca2+, Mg2+, HCO3— and the tem- perature have strong correlation to spring discharge. The water is undersaturated with respect to calcite and dolomite and the correlation of SIc and SId to discharge are strong, also. The chemistry of Iskrets Spring is controlled chiefly by discharge and it is independent of the season of year. Comparing the coefficients of variations of Iskrets spring with similar literature data, this spring could be classified as conduit spring.
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The field pH and content of Ca2+, Mg2+, HCO3−, dissolved oxygen and other aqueous species have been measured in 29 spring waters and 29 well waters in folded and faulted Paleozoic carbonate rocks near State College, Pennsylvania. Most of the springs issue from limestone; most of the well waters are pumped from dolomite. Average specific conductances of the spring and well waters were 347 and 499 μΩ−1, respectively, with polluted well waters having conductances as high as 945 μΩ−1. Molar ratios as low as 0.6 in the well waters have resulted from incongruent solution of dolomite. Theoretical treatment of relationships between PCO2, pH and HCO3− content shows that solution of calcite or dolomite by undersaturated waters leads to increases in both pH and HCO3− content. This relation is approximately obeyed by the spring waters at an average CO2 pressure of 10−2.2 atm. In contrast, solution or precipitation of carbonates by waters near saturation with respect to them, results in inverse relationships of pH and HCO3−; a behavior closely obeyed by the well waters which have CO2 pressures up to 10−1.6 atm. Computer calculation of ground water saturation with calcite and dolomite at ground water temperatures (8–14°C) was made using remeasured solubility product data for calcite, and considering the effect of CaSO40, MgSO40 and MgHCO3+ ion pairs. Within the uncertainty of the chemical analyses and thermochemical data, 12 well waters and 3 spring waters were saturated with calcite, whereas 7 well waters and 3 spring waters were saturated with dolomite. None of the ground waters significantly exceeded saturation with respect to either carbonate.
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In karst regions where correlations between physical characteristics of springs and temporal variations in spring water chemistry have been found, spring water chemistry has been used to infer physical attributes of karst systems. Possible correlations between chemical and physical characteristics of springs were tested in the Inner Bluegrass Karst Region of central Kentucky where previous dye-tracing studies have identified two physically distinct spring types: local high-level springs discharging from shallow flow paths and major low-level springs discharging from a deep integrated conduit system.
GW circulation in two carbonate aquifers of Albania
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