Journal of the European Radon Association

Prediction of the radon priority areas in the Slovak Republic and its experimental verification

Thu, 18 Apr 2024 06:11:05 -0700

Background: The identification of the areas with increased indoor radon levels, generally referred to as “radon priority areas”, is an internationally recognized issue. Many scientific studies propose methods for locating such areas using measured soil characteristics.

Objective: To utilize a modified Neznal radon potential classification for mapping radon potential across the Slovak Republic and experimentally verifying the predictions of radon priority areas.

Methods: The study applied a modified version of the Neznal radon potential classification, using measurements of soil air radon concentration and soil gas permeability, to develop a radon potential map for the Slovak Republic. Municipalities with high radon potential were primarily selected for the experimental verification of radon priority area predictions. The verification process involved comparing measured indoor radon activity concentrations against predicted values, which were derived from a previous study correlating averaged indoor radon activity concentrations with averaged Neznal radon potential for selected municipalities.

Results: The investigation revealed an approximately linear relationship between the measured indoor radon activity concentrations and their predicted values, with a correlation coefficient R² = 0.43. Notably, in one municipality predicted to have medium-high radon potential, indoor radon concentrations exceeded the reference level of 300 Bq.m^-3 even in buildings constructed after 2008, highlighting the significant influence of soil radon content on indoor levels despite stricter building material standards. The analysis of radon priority areas in relation to bronchial and lung cancer mortality data across various districts in Slovakia did not show statistically significant results.

Conclusion: The proposed method of predicting radon risk areas is important for radiation protection of the population against high effective doses of radon and can contribute to the successful implementation of the National Radon Action Plan of the Slovak Republic.

Radon exhalation and health hazard assessment for various ceramic tiles used in Bangladesh

Sopan Das, Shahadat Hossain — Mon, 15 Apr 2024 10:32:53 -0700

Objective: Among various building materials, tiles are the most used decorative materials used worldwide. For the safe use of tiles at home and workplace it is required to select them properly based on radiation dose due to radon and gamma emission.

Experiments: Among various tiles available in the market, 25 different types of tiles were collected for this experiment. Collected tiles are then ground and stored in sealed cans for secular equilibrium. To measure gamma activity due to the radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K, High Purity Germanium (HPGe) detector was used. To store radon gas emitting from tiles, a big box was used. The activity concentration was then measured by a radon detector (RadonEye) by placing it inside the box.

Results and discussion: It was observed that ²²⁶Ra, ²³²Th, ⁴⁰K activity varies from 45 – 89 Bq/Kg, 77 – 110 Bq/Kg, and 321 – 694 Bq/Kg. The radium equivalent activity varies from 198.32 – 280.46 Bq/Kg, less than the recommended value of 370 Bq/Kg set by UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation). The activity concentration of radon varies from 31 – 71 Bq/m³. This is lower than the 300 Bq/m³ recommended by ICRP (International Commission on Radiological Protection). The radon exhalation rate varies from 0.179 – 0.409 Bqm⁻²h⁻¹. To assess radiological hazards associated with the tiles samples air absorbed dose rate, internal and external hazard index, gamma index, annual indoor and outdoor effective dose rate, and dose due to radon were also calculated.

Conclusion: Though the estimated values for external and internal hazards are below the recommended values, they may be safe for adults. As children have thinner skin and breathe more air due to high breathing frequency, they may receive more radiation than adults. Moreover, they are at a greater risk because of their developing bodies and long life expectancy post-exposure.

Experience from radon in soil gas comparison measurements held in Czech Republic and in other countries, 1992–2022

Milan Matolin, Matej Neznal — Thu, 28 Mar 2024 00:00:00 -0700

Radon ²²²Rn, an inert natural radioactive gas, a daughter product in the ²³⁸U natural decay series, a source of alpha radiation, together with its short-lived decay products is a dominant source of absorbed radiation doses in the population. Rocks and building materials are fundamental sources of radon in dwellings. Elevated indoor radon activity concentration in houses and workplaces, surpassing recommended reference levels, is not desirable. Since radon penetrates into the houses from the geological basement, various technical aids for protection of houses have been developed. Their individual application derives from the radon potential of a building site. Radon risk mapping of building sites became a standard procedure for gauging the local radon potential. Various instruments and techniques of measurements of radon activity concentration in soil gas (Bq/m³) at building sites are available. Since radon in soil gas and radon measurement techniques are affected by several natural and technical conditions, resultant values of radon risk mapping by individual organizations vary, sometimes fundamentally. Radon comparison measurements at selected reference sites are an important tool for single organizations to verify their radon measuring procedures and reliability of their reported results. Based on legislative regulations, comparison measurements at established radon reference sites are a part of the obligatory activities for radon risk mapping at building sites in the Czech Republic. Experience and analyses of 30-year radon in soil gas comparison measurements in the Czech Republic show the dispersion of values reported by participating organizations and indicate that more than 10% of participants do not fulfill the established local criteria. This paper introduces requirements for the establishment of radon reference sites, documents their natural variability, recommends the procedure of radon comparison measurement, and analyses its results. A long-term experience was gained by testing organizations from the Czech Republic (1992–2022) as well as from the international comparison measurements organized in the Czech Republic and in several other countries (2010–2021).

Radon levels in three fish rearing buildings at Cleghorn Springs State Fish Hatchery, Rapid City, South Dakota, USA

Thu, 18 Apr 2024 06:25:18 -0700

Fish hatchery workers may be exposed to potentially health-threatening radon gas liberated from ground water used during fish rearing. This study surveyed the radon levels in three fish rearing buildings (small tankroom, tankroom, and rearing pavilion) at Cleghorn Springs State Fish Hatchery, Rapid City, South Dakota, USA. Overall radon values ranged from below the detection limit in all three buildings to a high of 2,317.68 Bq/m³ (62.64 pCi/L) in the tankroom. The pavilion had the lowest mean ± SE value of 56.57 ± 40.71 Bq/m³ (1.23 ± 0.11 pCi/L), while the highest mean value of 796.21 ± 54.61 Bq/m³ (23.67 ± 1.34 pCi/L) was in the small tankroom. Maximum radon levels were 1,231.36, 2,317.68, and 365.93 Bq/m³ (33.28, 62.64, and 9.89 pCi/L) in the small tankroom, tankroom, and pavilion, respectively. Radon levels were significantly correlated with the number of tanks receiving water in both the small tankroom and tankroom, but no such correlation was observed in the relatively open-air pavilion. Even though the water at the hatchery was aerated outside, additional aeration from rearing tank spray bars inside the enclosed small tankroom and tankroom resulted in relatively high radon levels.