Geology and Land-use related pattern of spring water quality. Case study from the catchments of the Malopolska Upland (S. Poland)

J. Siwek

Description

Abstract
Spring water chemical composition was investigated in three catchments (i.e. Pradnik, Dlubnia and Szreniawa) located within a carbonate-rock monocline from the Upper Jurassic and Cretaceous periods and constituting voluminous aquifers. The total spring water dissolved solids (TDS) displayed a concentration increase between 1974 and 1999. Using principal component analysis (PCA), the authors identified factors determining spring water chemistry. The research focused on making a distinction between the regional (large-area) and the local factors, the latter being related to the land-use in the direct vicinity of the springs. PCA yielded evidence that local sources of pollution can significantly contribute to the differentiation of spring-water chemical composition.

Sujets

• Hidrogeología
• Manantial
• Hydrogeology
• Springs
• Nitrato
• Nitrate

Informations

• Publié par: erevistas
• Publié le: 01 janvier 2004
• Nombre de lectures: 18
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Geologica Acta, Vol.2, Nº2, 2004, 167 -174
Available online at www.geologica-acta.com
Geology and land-use related pattern of spring water quality. Case
study from the catchments of the Malopolska Upland (S. Poland)
J. SIWEK and W. CHELMICKI
Jagiellonian University, Institute of Geography and Spatial Management
31-044 Cracow, Grodzka 64, Poland, Siwek E-mail: [e-mail]
Chelmicki E-mail: [e-mail]
ABSTRACT
Spring water chemical composition was investigated in three catchments (i.e. Pra ˛dnik, Dlubnia and Szreniawa)
located within a monocline made up by the Upper Jurassic and Cretaceous carbonate rocks that constitute volumi-
nous aquifers. The total spring water dissolved solids (TDS) displayed a concentration increase between 1974 and
1999. Using principal component analysis (PCA), the authors identified factors determining spring water chem-
istry. The research focused on making a distinction between the regional (large-area) and the local factors, the lat-
ter being related to the land-use in the direct vicinity of the springs. PCA yielded evidence that local sources of
pollution can significantly contribute to the differentiation of spring-water chemical composition.
KEYWORDS Hydrogeology. Springs. Groundwater quality. Groundwater pollution. Nitrates.
INTRODUCTION This paper aims to identify the role of the local and
regional factors having impact onto the chemical compo-
Spring water itself and specifically its chemical composi- sition of spring water at the Malopolska Upland using as
tion and physical properties reflect the processes going on in case studies catchments of three rivers, i.e. the Pra ˛dnik,
the relevant geological environment. Rather than drawn Dlubnia and the Szreniawa, all running in the southern
mechanically from water-wells, spring water runs to the sur- part of the upland (Fig. 1). This project was triggered by
face naturally, thus maintaining its properties developed in information whereby spring water dissolved solid (TDS)
the process of the natural circulation in the bedrock environ- increased in the area over the last 25 years. Thus, the
ment. Understanding spring water chemistry and physics is research had to answer the following questions:
particularly important in monitoring research aimed at
assessing environmental impact. As a result of human activi- - What caused the increased TDS in spring water?;
ty the quality of spring water has been undergoing increasing and
change. Such change can take place on a large, regional - Were these causes of regional or just local nature
scale or on local scale, limited to just the nearest vicinity of related to merely local pollution sources?
the effluent. It is scientifically and practically important to
understand the extent of the change to the spring water quali- To assess the rise of spring water concentration, the
ty over a period of time (in terms of years) and to identify comparison was made between the TDS values in 1974
what has been causing the change (local or regional factors). and 1999. Principal Component Analysis (PCA) was
© UB-ICTJA 167J. SIWEK and W. CHELMICKI Spring water quality related to Geology and land-use
FIGURE 1 Geology of the study area.
applied to identify factors crucial for the spatial pattern in limestone formed in massive limestone and bedded lime-
spring water chemistry. Similar approach to spring water stone, up to 230 m in thickness. The rocky outcropping
hydrochemical interpretations was presented for 243 watershed ridges are as high as 400-500 m above sea lev-
springs of Reunion by Join et al. (1997). In our study par- el and the valleys cut down to 250-300 m. At certain loca-
ticular attention was paid to the identification of the tions, the limestone structure is highly cracked and sub-
human influence, whether on a regional or local scale. ject to karst processes. At the watershed ridges, the
Chemical composition was compared both between and ground water table may be as deep as 100 m. There are
within the catchment basins. Additionally, the land-use in numerous springs of various discharge in the beds of the
the immediate vicinity was probed for any relationship valleys, typically of the karst gorge type. Most of the
with the chemical composition of the spring water. springs yield between 1 and 5 litres per second; larger
sources are few and far between.
AREA DESCRIPTION The Cretaceous aquifer is built chiefly of Upper Cre-
taceous marl, limestone and gaize, gradually growing in
The Malopolska Upland constitutes a portion of an thickness from a few dozen metres in the west to 800-
upland belt in southern Poland. The southern part of the 1000 m (for the entire Cretaceous formation) in the east.
Malopolska Upland consists of a vast monocline dipping The much-cracked and surface-weathered marls are
towards ENE. In the W and SW, the monocline is built of exposed to rainwater infiltration. At the watershed ridges
Triassic dolomites; as the structure continues in the direc- that reach 350-400 m, the ground water table can be as
tion of NE, the dolomites are overlaid, in the upland’s deep as in excess of 100 m. Just as in the Jurassic aquifer,
middle part, by Jurassic limestone and, farther on, the springs occur in the valleys, but the proportion of springs
limestone is overlaid by Cretaceous marl and limestone with discharge of greater than 5 litres per second is high-
(Fig. 1). The bedrock structures are partly covered by er. Clusters of several high-discharge springs, some
Quaternary loess formations of varied thickness. The Tri- exceeding 100 litres per second, are found at fault zones.
assic, Jurassic and Cretaceous formations constitute large
2aquifers. The rivers, Pra ˛dnik (catchment area: 141 km ), Dlubnia
2 2(286 km ) and Szreniawa (595 km ) are all left-side tribu-
The Jurassic aquifer consists mainly of Upper Jurassic taries of the Vistula river. The southwesternmost of the
Geologica Acta, Vol.2, Nº2, 2004, 167-174 168J. SIWEK and W. CHELMICKI Spring water quality related to Geology and land-use
researched rivers, the Pra ˛dnik, drains the Upper Jurassic each of the measured source, making the result not entire-
aquifer, while the Szreniawa river at the opposite side of ly representative, the consistently higher value of the dis-
the research area drains the Upper Cretaceous aquifer. solved solids in all cases clearly indicated an upward
The middle catchment of the Dlubnia river is located at trend. As the measurements taken in 1974 did not include
the contact of the two aquifers where the Upper Jurassic the ion content, the actual components contributing to the
sediments dip towards the NE under the Cretaceous sedi- increase could not be identified. However, based on the
ments (Fig. 1). chemical analysis of the spring water performed in 1999
and on systematic studies conducted during 2000-2001
The area is dominated by farmland (70-80%) and the (Siwek, 2002), an attempt can be made at identifying the
only continuous forest, the Ojcowski National Park, is human-contribution to the development of spring water
found in the Pra ˛dnik catchment. However, the mostly chemical pattern.
small-sized farms (typically a few hectares) are engaged
in a rather low-intensity activity with little fertiliser use
(90 kg NPK/ha in 2000). Over the last 30 years, the GENERAL CHEMICAL PATTERN OF SPRING WATER
development of rural water supply systems was not
matched by the same rate in the development of sewage During 2000-2001, a focused research project cov-
systems. Hence, the underground waters have been ered 74 springs in the three river catchments (the
exposed to potential pollution from inadequately insulat- Pra ˛dnik, Dlubnia and Szreniawa). The chemical composi-
ed individual sewage tanks and wildcat sewage dumping tion was sampled in either one-month intervals (22
directly into rivers. Other threats include general air pol- springs) or three-month intervals (52 springs).
lution from the neighbouring heavy industry located in
the Upper Silesia region (coal mining and steel industry), During the period, the spring water TDS typically fell
3the town of Olkusz (zinc and led mining) and in the city within the range of 200-500 mg/dm (90% of samples),
3of Cracow (steel sector). with the maximum-recorded value of 677 mg/dm . The
highest TDS and macro-element concentrations were
measured in the springs fed by the Upper Cretaceous
DISSOLVED SOLIDS IN SPRING WATER IN 1974 aquifer (the Szreniawa catchment), while the lowest val-
AND 1999 ues came from the Jurassic aquifer (the Pra ˛dnik catch-
ment) (Table 1). Typically, the samples revealed two-ion-
In 1974, across the Malopolska Upland major features type water of the HCO -Ca type (Fig. 3). Only some of3
of springs were measured, including springs located with- the springs in the Szreniawa and Dlubnia catchments
in the catchments of the Pra ˛dnik, Dlubnia and Szreniawa periodically changed their hydro-chemical type into the
(Dynowska, 1983). The research was repeated in 1999 HCO -Ca-Mg or SO -HCO -Ca types. 3 4 3
(Chelmicki, 2001; Chelmicki and Siwek, 2001). When
compared, the total dissolved solids measured in 1999 The dissolved nitrogen occurred in the spring water
were always higher than in 1974, whenever values for practically only in the form of nitrates. Nitrate concentra-
- 3both years were available (Fig. 2). While the comparison tion ranged from 1.7 to 60.6 mg NO /dm . As a result of3
was admittedly based on