International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

Natural radioactive nuclides in the thermal waters of the Polish Inner Carpathians

Pages: 343 - 351

Authors: JAKUB NOWAK, DINH NGUYEN CHAU, LUCYNA RAJCHEL

Abstract: The chemical compositions and activity concentrations of 238U, 234U, 226Ra, 228Ra and 222Rn were measured in the thermal waters occurring in the Podhale Trough. This region, part of the Polish Inner Carpathians, is the artesian basin situated between two groundwater recharging zones, the Tatras to the south and the Pieniny Klippen Belt to the north. The thermal water samples were collected from nine selected boreholes with the depths from 1113 m (Zakopane IG-2) to 5526 m (Banska Nizna IG-1). The waters belong to four hydrochemical types: HCO3-SO4-Ca-Mg-Na, SO4-HCO3-Cl-Na-Ca, SO4-Ca-Na and SO4-Cl-Ca-Na. Their mineralization and temperature range from several hundreds to 2500 mg/l and 23.9 to 86.3 °C, respectively. Excluding the waters from the Szymoszkowa GT-1 and Chocholów PIG-1 boreholes, the activity concentrations of the uranium and radium isotopes in the waters are relatively low and vary from decimals to above ten mBq/l and from several tens to about 600 mBq/l, respectively. They are classified as radon-poor waters. The phenomena mentioned seem to be characteristic of the waters draining limestone formations overlaying the crystalline rocks, namely the principal aquifers in the Tatras. The significant levels of the uranium and radium activity concentrations in the waters from Szymoszkowa GT-1 and Chocholów PIG-1 can be connected with the presences of Lower Triassic black shales with tuffites rich in uranium in the respective recharge areas. Comparing the parameters of the Podhale thermal waters with those of some selected thermal waters occurring in other regions of Poland and in north-west Croatia, the French Massif Central, Spanish Andalusia and north-east Tunisia, the authors found that the temperature of the thermal waters is contained between 16 and about 100 °C; the mineralization and concentrations of radionuclides vary in broad intervals and are considerably affected by the lithology and the geological structure of the region. The 226Ra activity concentration exceeds that of 228Ra in almost each of the thermal waters compared, which is similar to the waters from Podhale.

Keywords: Inner Carpathians, Poland, thermal water, mineralization, natural radioactivity

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