Beata Kozłowska

Determination of 222Rn in natural water samples from health resorts in the Sudety mountains by the liquid scintillation technique.

A method involving a Wallac 1414 WinSpectral alpha/beta liquid scintillation counter for determining 222Rn in aqueous samples is described. Samples were collected from 23 springs and 4 taps in health resorts of the Klodzka valley in the Sudety mountains in Poland. Half of the investigated spring water samples were radon enriched with an activity concentration higher than 74 Bq/l. In the tap waters the radon concentration level is very low or below the lower limit of detection. Owing to the statistical nature of radioactive decay the uncertainty of the measurement was determined as the standard deviation of 222Rn activity. The method introduced is fast and simple and does not require a chemical sample preparation procedure.

Radon-222 and 226Ra concentrations in mineralized groundwaters of GorzanÓw (Kłodzko Basin, Sudeten Mountains, SW Poland)

This work characterizes the occurrence of radionuclides 222Rn and 226Ra in the mineralized groundwaters of Gorzanów. The village is situated in the Sudeten Mountains, which are known in Poland for having increased concentrations of the aforesaid radionuclides in their groundwaters. However, in Gorzanów, the measured concentrations of 226Ra were low both in the reservoir rocks and mineralized waters. Consequently, the 222Rn concentration in the groundwaters also turned out to be low. The 226Ra content of these waters should mainly be associated with the dissolution of this nuclide, together with other main ions, at large depths, at slightly enhanced temperature. Radon-222, on the other hand, penetrates into the water during its outflow to the surface, in the zones of intensive friable deformations near fault zones. Thus, in the groundwaters of Gorzanów, the concentrations of these nuclides, subsequent in the uranium series, do not have a common genesis and they are not correlated with each other.

Mean annual 222Rn concentration in homes located in different geological regions of Poland – first approach to whole country area

The paper presents the results of year-long measurements of radon ((222)Rn) concentration inside 129 buildings in Poland in relation to the geological conditions of their foundation. The authors took into account the division of the country into tectonic units, as well as the lithology of the rocks forming the bedrock of these buildings. As expected, the highest value of mean annual (222)Rn concentration (845 Bq/m(3)) was recorded in a building situated in the area of the Sudetes, while the highest geometric mean (characteristic of the expected log-normal data distribution) was calculated based on measurements from buildings located within the East-European craton, in the area of Mazury-Podlasie monocline, where it reached 231 Bq/m(3). Such results reflect geological conditions - the occurrence of crystalline rocks (especially U- and Ra-enriched granites and orthogneisses) on the surface in the Sudetes, and of young post-glacial sediments containing fragments of Scandinavian crystalline rocks, also enriched with U and Ra, in the area of Mazury-Podlasie monocline. However, the least expected result of the investigations was finding out that, contrary to the hitherto widespread belief, none of the major tectonic units of Poland can be excluded from the list of those containing buildings with mean annual (222)Rn concentration exceeding 200 Bq/m(3). The mean annual concentration of radon for all the buildings were much higher than the mean concentration value (49.1 Bq/m(3)) of indoor radon in Poland quoted so far. These results cast a completely new light on the necessity to perform measurements of radon concentration in residential buildings in Poland, no more with reference to small areas with outcrops of crystalline rocks (especially the Sudetes, being the Polish fragment of the European Variscan belt), but for all the major tectonic units within Poland.

Assessment of radiation exposure outside the radiotherapeutic room during medical accelerator beam emission with the use of TL detectors (radiation exposure outside a LINAC room).

Photon and neutron soft tissue absorbed doses near the entrance door to the medical LINAC treatment room were measured with the use of thermoluminescent detectors LiF:Mg,Cu,P in the anthropomorphic phantom. Two different therapeutic beams (6 and 15 MV) and four treatment techniques were involved in the present study. This allowed one to investigate the contribution of scattered X rays, secondary neutrons and gamma rays to the radiation field. Photon absorbed dose rates 50 cm away from the LINAC room door during emission of 15-MV X rays varied between 4.1×10(-4) and 5.6×10(-4) Gy h(-1), depending on the gantry position and the irradiation field size, whereas in the case of 6-MV therapeutic irradiation these doses are ∼1.5 times lower. In the case of 15-MV beam emission, a mixed radiation field near the bunker door is observed with the photon radiation as the main component, which includes a 33.1 % contribution of the induced gamma radioactivity and ∼2.1 % contribution of the neutron radiation.

The detailed analysis of natural radionuclides dissolved in spa waters of the Kłodzko Valley, Sudety Mountains, Poland.

A survey was conducted to measure natural radioactivity in spa waters from the Kłodzko Valley. The main goal of this study was to determine the activity concentration of uranium, radium and radon isotopes in the investigated groundwaters. Samples were collected several times from 35 water intakes from 5 spas and 2 mineral water bottling plants. The authors examined whether the increased gamma radiation background, as well as the elevated values of radium and uranium content in reservoir rocks, have a significant impact on the natural radioactivity of these waters. The second objective of this research was to provide information about geochemistry of U, Ra, Rn radionuclides and the radiological and chemical risks incurred by ingestion of isotopes with drinking water. On the basis of results obtained, it is feasible to assess the health hazard posed by ingestion of natural radioactivity with drinking waters. Moreover, the data yielded by this research may be helpful in the process of verification of the application of these waters in balneotherapy. In addition, annual effective radiation doses resulting from the isotopes consumption were calculated on the basis of the evaluated activity concentrations. In dose assessment for uranium and radium isotopes, the authors provided values for different human age groups. The obtained uranium content in the investigated waters was compared with the currently valid regulations concerning the quality of drinking water. Based on the activity concentrations data, the activity isotopic ratios (234)U/(238)U, (226)Ra/(238)U, (222)Rn/(238)U, (222)Rn/(226)Ra and the correlations between radionuclides content were then examined. In brief, it may be concluded on the basis of the obtained results that radon solubility is inversely proportional to radium and uranium dissolution in environmental water circulation. The presented study allows conclusions to be drawn on the radionuclide circulation among different environmental biota: from lithosphere through hydrosphere to biosphere.

Investigation of the influence of chamber construction parameters on radon exhalation rate

Abstract Radon exhalation from ground is a process dependent on the emanation and migration of radon through ambient air. Most studies on radon exhalation from soil were performed regarding the influence of meteorological and soil parameters. As radon exhalation rate can be affected by the internal properties of the sample, it may also be influenced by the exhalation chamber geometry such as volume-to-area (V/S) ratio or other construction parameters. The measurements of radon exhalation from soil were made using different constructions of accumulation chamber and two types of radon monitors: RAD7 (Durridge) and AlphaGUARD PQ2000PRO (Genitron). The measurements were performed on one site in two locations and approximately at the same time. The first tests did not show the correlations of exhalation rate values and the chamber’s construction parameters and their geometrical dimensions. However, when examining the results, it seems that there are still too many factors that might have affected the process of radon exhalation. The future experiments are planned to be conducted in controlled laboratory conditions.

Analysis of dosimetric peaks of MgB4O7:Dy (40% Tefl on) versus LiF:Mg,Ti TL detectors

Abstract Magnesium tetraborate doped with dysprosium (MgB4O7:Dy) is known as a good thermoluminophor for personal dosimetry of gamma ray and X-ray radiation because of its high sensitivity and close tissue equivalence. This material can be produced by different routes. The sintered pastilles of magnesium tetraborate mixed with Teflon (40%) used in this work were manufactured at the Federal University of Sergipe, Department of Physics by the solid-state synthesis. Magnesium tetraborate was already used for high-dose dosimetry, exhibiting linearity for a wide range of doses. In this work, the authors examined its main characteristics prior to potential use of detectors in everyday dosimetry, comparing this material to a widely used LiF:Mg,Ti phosphor. The following tests influencing dosimetric peaks of MgB4O7:Dy were presented: (1) the shape of the glow curves, (2) annealing conditions and post-irradiation annealing and its influence for background of the detectors, (3) the choice of the heating rates at the read-out and (4) the threshold dose, that is, the lowest possible dose to be measured. Similar tests were performed with LiF:Mg,Ti detectors, produced and widely used in Poland. The results were compared and discussed.

The study of natural and artificial radionuclides incorporation in teeth and head bones of animals lived nearby Caetité uranium mine, Brazil

This study aimed at assessing the incorporation of radionuclides in animals in the proximity of the uranium mine in Caetité, Brazil. In 2014, samples of bovine and equine teeth and skull bones were collected and their contents of natural and artificial isotopes were assessed using nuclear spectrometry techniques. Gamma ray emission from 226,228Ra and 40K isotopes was determined using high-purity germanium (HPGe) spectrometry, 90Sr radioactivity was measured with liquid scintillation, and 234,238U, 232,230,228Th, 210Po and 239+240Pu radioactivity was assessed with alpha-spectrometry. Prior to the measurements, sample dissolutions and isotope separations were performed. Our results indicate a high 228Th isotope content in the skull bones and the teeth of animals, up to 179 Bq per kg of ash. The 226Ra and 228Ra concentrations were slightly lower. Activity concentrations of other isotopes were significantly lower or below the detection limit. We could not identify sources of technologically enhanced levels of 228Ra in the area we investigated; therefore we suggest that their origin is natural.