Zone-Related Variability of Radon Exhalations in Nałęczów Region

Abstract

The studies on the radioactivity of waters in health resorts around the world have been conducted for over a hundred years. At first, they were strictly connected with the use of radioactive radon 222Rn for the purpose of treating patients. In Health Resort Nałęczów, the first studies on the content of radon in water were carried out in 1909. Encouraged by promising results, an attempt was made to expand the treatment possibilities/potential of this resort. Balneological treatment procedures were devised; however, they were not implemented in practice. In the following years, no research on the radioactivity of waters in Nałęczów was conducted. In 2005, pilot measurements of radon exhalations were carried out in the vicinity of Lublin. Their results showed no significant concentrations of radon in the air. The paper presents the results of radon studies performed in the years 2009-2011 in the water intake area of the resort and its proximity. The measurements of radon exhalations and its content in water were conducted. The former were carried out using the CR-39 passive dosimeters at the underground level, above the aquifer. Measurements of radon concentrations in soil air and water were performed in selected locations. In the areas in which abnormally high radon exhalations were detected, additional measurements were made using active methods by means of an Alpha GUARD PQ 2000 PRO meter. The performed studies enabled to determine the background exhalation values as 42-190 Bq/3. According to the contemporary knowledge, these values correspond to the concentrations detected in other regions of Lubelskie Voivodeship and the strip of Polish low- and highlands. In the water intake area of the resort, as well as selected parts of Bystra river valley and the Kocianow rift fault, the radon concentrations of 1130-4535 Bq/3 were detected. Such high concentrations should be considered abnormally high, and have not been previously noted in the Lubelskie Voivodeship. These concentrations are comparable to the ones in Sudety mountains and certain parts of Carpathian Mountains. Radon exhalations in the underground mining excavation measured with active method in open crevices and cracks of paleogene rocks reached the value as high as 14110 Bq/3. Locally, water in the zones of elevated radon exhalation levels (except for the resort) can be considered as radon-poor. Zone-related variability of radon exhalations connected with the local tectonic, lithological, and hydrogeochemical conditions of rock mass in this part of Lublin Upland, was determined in the paper. Most probably, the source of radon constitutes glauconite layers with phosphorites from the borderline of Cretaceous and Paleogene. The transportation of radon to the ground level and building cellars is induced and directed by the local tectonics, cracks in rock mass and the flow of water within. Significant difference in the 222Rn-saturation level of iron springs and normally-mineralized waters in similar hydrodynamic conditions, is an interesting phenomenon. Determining a possible influence of ferric ions on the emanation coefficient requires further research, especially as this issue has not been previously investigated. Another important problem is the detection of radon concentrations (over 200 Bq/3) in the existing and designed objects in Nałęczów and its vicinity. Repeating the research on the prospective balneological use of radon in Health Resort Nałęczów – which was conducted a hundred years ago – seems justified as well