The authors’ research has shown that the maximum values of ²²²Rn activity concentration in all granitoid massifs of Poland exceed 100 Bq·L⁻¹, i.e. the value allowed for waters intended for human consumption. Such waters should be de-radoned prior to being distributed through the water supply networks. Even more common in these areas is the occurrence of potentially medicinal radon waters, i.e. waters characterized, in accordance with Polish law, by radon activity concentration of at least 74 Bq·L⁻¹. Such waters may be used for balneotherapeutic treatments. For the Karkonosze, Strzegom-Sobótka, Kłodzko-Złoty Stok and Kudowa massifs, the range of hydrogeochemical background of ²²²Rn exceeds both 74 and 100 Bq·L⁻¹. This indicates common occurrence in these areas of both potentially medicinal radon waters and waters which require de-radoning before being supplied for human consumption. More than 50% of groundwaters from the Karkonosze granite area contain over 100 Bq·L⁻¹ of ²²²Rn. This means that these waters are mostly radon and high-radon waters. The remaining massifs contain predominantly low-radon waters and radon-poor waters. The ²²²Rn concentrations obtained by the authors are comparable to values measured in groundwaters in other granitoid massifs in the world, creating both problems and new application possibilities.

Radioactive (radon) groundwaters are highly valued among mineral waters for their healing effects. Between 2005 and 2015, a large exploratory event for prospecting and documenting radon water springs took place in the crystalline area of Lugicum (Bohemian Massif) under Czech–Polish cooperation. For these purposes, an exploration method was developed as a combination of GIS (ArcMap 9.1–10.2) area preparation followed by field radiohydrogeochemical mapping at a scale of 1:10,000. The gamma indication method was optimized and used for the selection of water samples. A total of 2354 water sources were examined. Radon activity concentrations were measured at 660 sources found throughout the territory. Of those, 111 sources exhibited ²²²Rn activity above 1500 Bq/L and, thus, were categorized as sources of mineral radioactive waters according to Czech legislation. The highest ²²²Rn activity was found in the Michael spring near Nové Město pod Smrkem (up to 6237 Bq/L ²²²Rn). Many discovered sources with high balneological potential are significant and, therefore, are quickly becoming popular among the public.

Natural radioactive isotopes occur in various components of the natural environment, including groundwater. The general population, not always aware of possible threats, can use its resources. The activity concentration of some of the radioactive isotopes should be monitored, especially in those intakes from which it is possible to obtain water for human consumption, e.g. in domestic wells. The conducted research was innovative due to the fact that in many countries, including Poland, there are no regulations on waters exploited from home wells using as a drinking water source. As the groundwaters from this area have not been examined for radon (²²²Rn) and radium (²²⁶Ra) occurrence yet, the goal of this research was to perform screening tests in this part of the Fore-Sudetic Monocline. For this purpose, the authors have measured the concentration of ²²²Rn and ²²⁶Ra activity in groundwater collected from this geological unit located in south-western Poland. ²²²Rn and ²²⁶Ra occurrence was researched, and specific electrolytic conductivity, redox potential, pH and temperature were measured in 52 groundwater samples. ²²²Rn activity concentration ranged from 0.18 to 19.78 Bq/dm³. Only in three cases, ²²⁶Ra activity concentration reached a value above the lower detection limit of the applied method, i.e. 0.05 Bq/dm³ (max. 0.77 Bq/dm³). The authors present completely new data on the occurrence of these radioactive isotopes in the waters of the first aquifer in the Fore-Sudetic Monocline, which is not without significance for the health of consumers of these waters.

Authors selected 5 intakes of groundwaters outflowing from carbonate rocks in Roztocze region in Poland and measured activity concentrations of ²²²Rn and ²²²Ra. The average values of ²²²Rn and ²²⁶Ra activity concentrations were: 5.3 (min. 2.0, max. 8.3 Bq/dm³) and 0.06 Bq/dm³ (from <0.06 to 0.07 Bq/dm³) respectively. To make a comparison authors made also investigations in groundwaters from other regions built of carbonate rocks in Poland (Sudetes, Kraków-Częstochowa Upland, Lublin Upland, Tatra Mountains). In groundwaters from these regions, ²²²Rn activity concentration was from 2.2 to 47.8 Bq/dm³, while mean value was 16.0 Bq/dm³. All of ²²⁶Ra activity concentration values measured in these regions were below LLD (< 0.05 Bq/dm³). Results from Roztocze and other regions are comparable. All of investigated waters according to new polish regulations about limits of ²²²Rn and ²²⁶Ra activity concentrations could be used as drinking waters (the limits of ²²²Rn and ²²⁶Ra activity concentrations are 100 Bq/dm³ and 0.5 Bq/dm³ respectively).