Thermal and mineral waters in north-eastern Slovenia

 The Mura basin in north-eastern Slovenia is made up of two depressions, developed during the Late Neogene and Early Pliocene all within a widespread system of Pannonian basins. Both depressions are characterized by the occurrence of thermal waters of somewhat different hydrogeochemical character. Radgona depression is in the northern part of the basin and reaches depths of about 2 km. Thermal waters are generally dominated by sodium-bicarbonate, not related to the age of an aquifer, its wallrock composition, the type of porosity or total concentration of dissolved solids. Locally, sulphate-rich waters are encountered, and they are related to the presence of gypsum in the rocks of pre-Tertiary basement. The adjacent Ljutomer depression is over 4 km deep and comprises compartments with stagnant or semi-stagnant aquifers. Herein saline waters predominate, even in the aquifers of carbonate composition and abundant CO₂ gas. In shallower, unconsolidated, intergranular aquifers sodium-bicarbonate waters predominate. Thermal aquifers of this type are very important to the economy of the region, but they are also subjected to overexploitation which is reflected in time-dependent changes of dynamic pressures, temperature, conductance, salinity, pH and concentration of major ions, trace elements, dissolved gasses, and total organic carbon. Mineral waters occur in shallow aquifers or springs in marginal areas of the Radgona depression. Bicarbonate waters are dominated by calcium, or both calcium and sodium. Some mineral waters are formed mainly by penetration of CO₂ gas into shallow aquifers and consequent water–rock interaction. Composition of some mineral waters indicate their possible evolution from thermal waters which have risen from central parts of the Radgona depression along deep-seated faults, and have been modified by cooling and mixing processes. Received: 30 November 1998 · Accepted: 22 March 1999     

Formation of mineral and thermal waters of some artesian basins in Russia

Artesian basins contain the largest mineral water resources of the world. There are several types of mineral therapeutic water: sulfate, chloride, radon-rich, iron-rich waters, etc. Artesian basins occupy very large areas in Russia. However, genesis of water and brines is still not very clear. This is one of the most important hydrogeological problems that is being attempted to solve for many years. Most of the Russian hydrogeologists traditionally consider that these waters are of sedimentary origin. However, higher concentrations of bromine, iodine, iron, radon and other balneologically active components can be of different origin, for example, of infiltration or juvenile water. As an example, two areas will be considered – West-Siberian basin and East-European artesian area.West-Siberian artesian basin has very distinct latitudinal and vertical zonation. Latitudinal zonation is caused by climate changes from north to south. As for the vertical zonation, mineralization and chemical composition change in the vertical cross-section and from the periphery to the center within the same aquifer. The main mineral water resources of West-Siberian artesian basin are concentrated in Mesozoic rocks. Brackish waters and low-saturated brines without specific components are used for medical purposes. The most well-known spa is Karachi, which exploits chloride-hydrocarbonate brackish water. Sodium chloride bromine and iodine-bromine waters are used at other health resorts. It is possible to organize extraction of iodine from brines of Tcherkashinsko-Tobolskoe occurrence in Tumen region.East-European artesian area occupies most of the Russian Platform. The most widespread types of mineral water within the Russian Platform are sodium-chloride and magnesium-sulfate waters and brines. Such well-known spas, like Moscow mineral waters, Krainka, Staraya Russa and many others, belong to this type. Resources of these waters are definitely connected with sedimentogenic processes. The upper hydrodynamic zone contains iron-rich, hydrogen sulfide, and sometimes radon-rich water. Their formation is caused by the interaction between waters of infiltration and sedimentary genesis, or between infiltration waters and host rocks. One of the examples is Polustrovo iron-rich water. There are industrially valuable waters containing bromine and iodine.The resources of therapeutic water of sedimentary basins allow to increase balneological potential of spas in Russia.     

Radon-rich waters in Russia

In radon mineral curative waters, according to Russian mineral water classification, the radon concentration should be greater than 185 Bq/l. There are about 30 mineral waters with high levels of radon in Russia. Radon-rich waters have high therapeutic effects. It is proven that natural background radiation stimulates the human immune system. Radon is a natural radioactive gas that has no taste, smell or color. Radon-222 is one of the heaviest elements in the zero groups of inert gases. It is a gaseous radioactive element. All radon isotopes are -emitters while the transformation of its decay products is accompanied by the emitting of -or -particles. The main products of radon decay are short-lived isotopes Po, Pb, Bi, and TL. Belonging to the uranium and thorium decay chain, radon isotopes form directly during the decay of radium isotopes. Therefore the radon concentration depends upon the concentration of its parent's isotope in water and rocks washed by it as well as upon the amount of radon emanation. Loose rocks or rocks with a great number of cracks are characterized by higher radon concentration (zones of tectonic disturbance, weathering crusts, etc.).Crystalline rocks usually have higher uranium concentrations than the average bedrock. Examples of rock types, which often have enhanced uranium concentration >5% ppm U includes the following: granites, syenites, pegmatite, acid volcanic rocks and acid gneisses. In the earth's crust radon migrates either in a gaseous or dissolved state. It can go to the surface without any chemical reaction. Formation of the radon-rich therapeutics waters of Russia has been analyzed, and most of them are genetically connected to crystalline acid rocks that have exceeded uranium-radium mineralization. The radon content in Russia reaches more than 8,000 Bq/l. Radon-rich waters of this type occur in the Altai, Karelia, St Petersburg and Trans-Baikal regions. Another type is connected to geodynamic activity of regions and secondary radioactivity. A well-known example of radon-rich waters of the second type is Pyatigorsk in the North Caucasus. Mixing confined carbon dioxide-hydrogen sulfide water and unconfined groundwater forms radon waters. The radon concentration is 1,170–2,430 Bq/l. The occurrence of radon-rich water deposits in other regions of Russia is described. Further investigation of the radon content in other geological environments will contribute to the environmental safety as well as to the solution to many genetic, hydrogeochronological, paleoreconstructive and prediction problems in hydrogeology.     

Joint Russian-American hydrogeological-geochemical studies of the Karachai-Mishelyak system, South Urals, Russia

 In September 1994, a Russian-American team conducted hydrogeological, geochemical, geophysical, and radiometric measurements in the territory of the Mayak Production Association, Russia. The primary purpose of these operations was to examine the frontal area of a radioelement- and nitrate-laden groundwater plume moving from the disposal site, Lake Karachai, toward the Mishelyak River. Activities encompassed (1) isolation of hydrologic intervals in two wells and production of water from these intervals, to compare isolated versus open-well sampling methods and to determine hydraulic transmissivities of the aquifer(s); (2) surface and soil-water sampling, accompanying radiometric measurements and subsequent chemical analyses; and (3) electrical resistivity profiling in areas of expected contrasting resistivity. Preliminary results indicate that (1) ⁶⁰Co, ¹³⁷Cs, and ⁹⁰Sr are present in small concentrations (∼0.1% of permissible levels) in water of the Mishelyak River; (2) analyses of water samples collected by a downhole sampler and of water produced from packed-off intervals agree within limits of laboratory accuracy, attesting to the efficacy of the sampling methods presently used by the Russian workers; (3) considerable differences in contaminant concentrations exist between nearby wells, supporting the concept that the plume from Lake Karachai toward the Mishelyak River is controlled by steeply dipping fractures and shear zones; and (4) strong contrasts occur between the electrical resistivities of soil and bedrock. Further collaborative work is strongly recommended and should include more detailed isolation of intervals in wells by multi-packer installations, to better determine the geochemical and hydrological characteristics of the Karachai-Mishelyak system; deployment of a broader soil water and soil sampling array; a more detailed examination of the distribution and concentration of radionuclides by high-resolution field gamma spectrometry; and a detailing of the area's electrical resistivity setting, using a mobile electromagnetic measurement system. Received: 22 January 1996 · Accepted: 1 April 1996     

Natural mineral waters,curative-medical waters and their protection

In Europe different types of water are marketed, each strictly defined by EC Directive 80/777 (Natural Mineral Water, Spring and Table Water) or 80/778 (Drinking Water). In Germany, an additional type of water is common in the market: curative/medical water. Product quality and safety, registration as medicine, and pharmaceutical control are defined by the German Federal Medicine Act. A medical water is treated as any other medicine and may be sold only in pharmacies. The use of any water in Germany is controlled and strictly regulated by the Federal Water Act (Fricke 1981). The following requirements are set by the act: (1) No water use without a permit, which is limited in time and quantity. (2) No single or juristic person may own water. (3) Water resources of public interest and their recharge areas are to be protected by the definition of water protection zones. (Natural mineral water is not of public interest and therefore is not required to be protected by the definition of water protection zones, although it represents a market value of more than US$2 billion. Medical water is of public interest). The definition of water protection zones impacts private property rights and has to be handled carefully. In order to protect water resources, sometimes the economic basis of a traditional industrial and/or agricultural infrastructure is destroyed. The concerns and needs all citizens, including industry, must be considered in analyzing the adequacy of water protection zones.     

The relationship between the water table and the surface flow of a losing stream, lower Medano Creek, Great Sand Dunes National Monument, Colorado

 Proposed groundwater withdrawals in the San Luis Valley of Colorado may lower the water table in Great Sand Dunes National Monument. In response, the National Park Service initiated a study that has produced a generalized conceptual model of the hydrologic system in order to assess whether a lowering of the water table might decrease the surface flow of lower Medano Creek. Based upon information obtained during the drilling of several boreholes, there appear to be five important hydrostratigraphic units underlying lower Medano Creek within the upper 30 m of the ground surface: 1. a perched aquifer overlying an aquitard located between about 5 and 6 m below the ground surface; 2. the aquitard itself; 3. an unconfined aquifer located between the upper and lower aquitards; 4. an aquitard located between about 27 and 29 m below the ground surface; and 5. a confined underlying the lower aquitard. Because the areal extent of the aquitards cannot be determined from the borehole data, a detailed conceptual model of the hydrogeologic system underlying lower Medano Creek cannot be developed. However, a generalized conceptual model can be envisioned that consists of a complex system of interlayered aquifers and leaky aquitards, with each aquifer having a unique hydraulic head. Water levels in the perched aquifer rise rapidly to their annual maximum levels in response to the arrival of the flow terminus of Medano Creek during the spring runoff event, and the location of the flow terminus is directly dependent upon the discharge of the creek. Water levels in the deeper, non-perched aquifers do not appear to fluctuate significantly in response to the arrival of the flow terminus, demonstrating that it is unlikely that the proposed groundwater withdrawals will decrease the surface flow of lower Medano Creek. Received: 27 December 1995 · Accepted: 20 February 1996     

Chemical composition of bottled mineral waters in Estonia

Five commercially available in Estonia brands of bottled water have been analysed for 59 chemical elements by ICP-QMS and ICP-AES techniques to assess the quality of domestic mineral waters in scope of the European Groundwater Geochemistry Project initiated by the Geochemistry Expert Group of EuroGeoSurveys. Contents of 9 cations and anions, pH and electrical conductivity (EC) were measured in the bottled mineral waters by IC, titration and photometric methods. The data showed a significant difference between natural undiluted mineral water (Värska Originaal) characterised by the highest values of pH, EC and majority of trace elements studied, and other domestic waters sold in Estonia.     

Hydrogeology of limited aquifer in a granitic terrain

 Detailed hydrogeological studies in a granitic micro-watershed have been carried out to determine the extent, behavior, and characteristics of the aquifer. The study includes analysis of lithologs, drill time log, pumping tests, and slug tests. Realistic field conditions have been taken into account for characterizing the aquifer system. Slug tests were carried out to estimate aquifer parameters at the wells which could not sustain pumping. Received: 20 November 1997 · Accepted: 23 February 1998     

Structural-tectonic features of accommodation deposits of mineral waters of Azerbaijan and their complex development

The geological structure of the territory of Azerbaijan is characterized by numerous mineral waters of various chemical, gas, microcomponental structure, temperature and medical properties which are distributed over the territories of the Republic and their physical and chemical features are closely connected to the geostructural conditions of the individual districts in which they are found.     

Investigation of the hydrogeochemistry of some bottled mineral waters in Hungary

Bottled drinking water constitutes a significant part of total water consumption in developed countries and national and EU legislation regulates their market production. In the framework of an international project carried out by the EuroGeoSurveys Geochemistry Expert Group 36 bottled waters were obtained from public markets in Hungary in order to determine their hydrogeochemical composition. The objective of this study is to investigate the possible relationship between groundwater aquifer lithology and the processed and marketed bottled waters, and to develop a classification of bottled waters, based on their dissolved mineral content. Analytical results of this study are compared with the composition shown on bottle labels, and with archive hydrochemical data from the producing wells. Results show that, while processing of original groundwater, such as oxygen addition, iron or hydrogen-sulphide removal can significantly alter water composition, bottled water composition can be used for selection of sites for detailed hydrogeochemical and hydrogeological characterization. A simple and useful classification of bottled water quality is also presented that is based on natural groups of sampled waters derived by means of statistical data analysis methods.     

Classification of natural mineral and spring bottled waters of Portugal using Principal Component Analysis

Considering its area, Portugal is one of the world's richest countries in mineral and spring waters. There are 33 different types of bottled water, 18 of which are classified as natural mineral water and the remaining as spring water. The majority of these waters are of low mineralisation in comparison to most European bottled waters.     

Hydrochemical evolution and environmental features of Salso River catchment, central Sicily (Italy)

 A hydrogeochemical study of the Salso River highlighted the chemical and isotopic space-time evolution along its flow path and the main contamination processes. Within the basin, three different hydrogeochemical facies have been individuated: (1) Ca-Mg-HCO₃, (2) Ca-Mg-SO₄ and (3) Na-Cl. The first facies reflects the chemical composition of the groundwaters hosted in the carbonate reliefs that belong to the Madonie Mountains. The second and the third facies are the result of the interaction processes between surface waters and the gypsum and salty clays, respectively. Two pollution sources have been also located in the basin downstream from the salt mine and downstream from a discharge area of wastewater from the town of Gangi. On the basis of the location of natural and anthropogenic pollution sources, the waters available for drinking and irrigation use are also indicated. Received: 16 July 1999 · Accepted: 22 December 1999     

Hydrogeology and sustainable agriculture

 The world's population continues to grow and to require more and more food. Attempts by modern high output agriculture to meet this need have led to serious environmental problems. A more sustainable balance is now required and is being sought in a variety of ways. Hydrogeologists should continue to highlight the threat posed by agriculture to groundwater, particularly since groundwater is a hidden resource and its degradation and rehabilitation often take place slowly. But the time has come for groundwater specialists to go further and become actively involved in helping to provide practical and sustainable solutions. The agriculture of the future requires a holistic approach which balances the essential economics of food production with equally valid environmental needs, including those of groundwater. Such an approach demands cross-sectoral collaboration involving multidisciplinary research and action within an integrated policy framework. This paper reviews the current groundwater/agriculture interface and some of the attempts being made to achieve a more truly sustainable agriculture with particular emphasis on European experience. It aims to stimulate greater interest and involvement by hydrogeologists in helping to bring about realistic solutions that will enable future generations to enjoy adequate good quality food and water. Received: 9 August 1996 / Accepted: 11 November 1996     

Overview of hydrogeothermics in Spain

 Hydrothermic features in Spain have been used since ancient times for therapeutic purposes. At present, the number of spas has decreased notably, although some of them have been restored for aesthetic reasons. From 1970 onwards hydrogeothermic energy started to be used. There are some boreholes and small facilities at several places in Spain, mostly on the Mediterranean coast and near Madrid. The hydrochemistry of spanish thermal groundwaters is directly related to the geological nature of granite and limestones where most important springs are located. Received: 9 November 1998 · Accepted: 11 May 1999     

Hydrogeology and geochemistry in the Curuksu (Denizli) hydrothermal field, western Turkey

 Curuksu is a low temperature hydrothermal system located within the upper sector of the B. Menderes Graben. The hydrologic structure of the Curuksu hydrothermal system is largely controlled by major graben faults where it is characterized by the presence of two thermal reservoirs. One is formed by Paleozoic quartzite, schist and marble units, and the second consists of Pliocene limestone-travertine units. The thermal conditions in the Curuksu region indicate that the regional tectonics and resulting local stress field control low temperatures activity. Temperatures of 30 springs emerging in the study area range between 15 and 55  °C. These springs are classified as cold fresh, warm mineral and thermal waters. Pamukkale, Karahayıt and Honaz springs are steam condensate waters, whereas Curuksu springs are commonly steam-heated waters with respect to the major anion concentrations. The reservoir temperatures have been estimated from chemical compositions by utilizing simultaneously, geothermometers and mixing models. According to these thermometric methods, the most probable subsurface temperature is in the range of 62–90  °C. However, the mixing models suggest a temperature level of 80  °C for the parent water. The system has low total dissolved solid (TDS) of ∼1000–1500 mg/l, which indicate that these waters undergo conductive cooling within the reservoir. Received: 9 September 1999 · Accepted: 14 February 2000     

Conditions of formation mineral waters in Sarissky Stiavnik and Radoma

Mineral waters in Sarissky Stiavnik and Radoma are formed on the tectonic fault zones of the Zlin formation and Makovica sandstones. Precipitation waters flow downwards thus becoming enriched in TDS content. The process is enhanced by inflow of CO₂ rich mineral waters of the Obidowa-Slopnice-Zboj unit, pushed by carbon dioxide and methane. Mineral waters in Sarissky Stiavnik and Radoma are of the Na-HCO₃ chemical type, typical for the mineral water springs of the Magura unit in this part of the flysch belt. The origin of chloride component in the TDS content can be found in the waters with thalasogenic mineralization beneath the Magura unit, where the Obidowa-Slopnice-Zboj unit is to be found. Hydrogeological structures in Sarissky Stiavnik and Radoma can be classified as combined hydrogeological structures, where the upper partial hydrogeological structure is opened (Magura unit) and the lower structure is semi-closed (unit Obidowa-Slopnice-Zboj).     

Temporal and spatial variations in density and velocity fields of the waters of Gareloch,Scotland

 Spatial variations in the density and velocity fields have been observed in the Gareloch (Scotland) during surveys in 1987–1988 and 1993–1994. The variation of the density field has been analyzed on a variety of time scales from semidiurnal to seasonal in order to quantify effects caused by the forcing factors of tidal mixing, freshwater input, and wind. Initial results indicate that water density in the loch is controlled (to a major degree) by the freshwater input from runoff from the local catchment area and from freshwater entering on the flood tide from the Clyde Estuary. It is estimated that during winter periods the high freshwater flows from the rivers Leven and Clyde into the Clyde Estuary account for up to 75% of the freshwater creating the density structure in the loch. Analysis of long-term dissolved oxygen data reveals that major bottom water renewals occurred between July and January in the years 1987–1994. Major bottom water dissolved oxygen renewals have a general trend but during the year sporadic renewals can take place due to abnormal dry spells increasing the density of the water entering from the Clyde, or consistently strong winds from the north reducing stratification in the loch and producing better mixed conditions. Velocities vary spatially, with the highest velocities of up to 0.6 m s^–1 being associated with the velocity jet effect at the constriction at the sill of the loch. Observed near-surface mid-loch velocities increased as the vertical density gradients in the upper layers increased. This indicates for the observed conditions that increased stratification in the upper layers inhibits the entrainment rate and hence rate of gain of thickness of the wind-driven surface layer, resulting in increased surface velocities for a given wind speed and direction. The main flow is concentrated in the upper 10 m and velocities below 10 m are low. Observed mean spring tide surface velocities are on average 30% greater than mean neap tide surface velocities. Received: 22 May 1995 · Accepted: 23 August 1995