Radon Concentration Levels Research Articles

Radon levels assessment in some Northern Romanian salt mines

Due to their low radioactivity background, underground salt mines spaces offer a unique possibility for speleotherapy use. The knowledge of radon concentration levels in such underground environments is essential for therapeutic purposes of different respiratory and rheumatic diseases. In order to develop speleotherapy in Romania, this paper presents the results of an indoor radon concentration levels survey in some salt mines in Romania. The survey was carried out using radon monitor Pylon AB-5 system methodology validated by a CIS-P5M system. In order to investigate whether differences in depth and microclimate parameters translate into significant differences in salt mine indoor radon concentrations, have been chosen three salts mine test sites placed in the Northern part of Romania (Turda, Cacica and Ocna Dej) in stable areas of the mining field at 32-120 m depth. Environmental microclimate conditions (mean values of air temperature 10-14.5 C, air humidity 65-80%, air velocity 0.2 m/s saline aerosols and low microbial factors) have anti-bacterial, anti-microbial, and anti-inflammatory properties and recognized therapeu- tically effects on human body's health. Air temperature is one of the most important factors which need to be con- sidered when carrying out a survey of indoor radon con- centrations in salt mines because temperature largely determines close spaces ventilation rates, and ventilation habits are known to have significant effects on indoor radon concentrations. The analyzed environmental conditions and recorded low levels of indoor mean radon concentration (6.9 ± 0.39 and 96.5 ± 4.76 Bq/m 3 ) demonstrated the best suitability of the investigated three salt mines in Romania for speleotherapeutic applications.

Calculating CR-39 Response to Radon in Water Using Monte Carlo Simulation

Introduction CR-39 detectors are widely used for Radon and progeny measurement in the air. In this paper, using the Monte Carlo simulation, the possibility of using the CR-39 for direct measurement of Radon and progeny in water is investigated. Materials and Methods Assuming the random position and angle of alpha particle emitted by Radon and progeny, alpha energy and angular spectrum that arrive at CR-39, the calibration factor, and the suitable depth of chemical etching of CR-39 in air and water was calculated. In this simulation, a range of data were obtained from SRIM2008 software. Results Calibration factor of CR-39 in water is calculated as 6.6 (kBq.d/m)/(track/cm) that is corresponding with EPA standard level of Radon concentration in water (10-11 kBq/m). With replacing the skin instead of CR39, the volume affected by Radon and progeny was determined to be 2.51 mm for one m of skin area. The annual dose conversion factor for Radon and progeny was calculated to be between 8.8-58.8 nSv/(Bq.h/m). Conclusion Using the CR-39 for Radon measurement in water can be beneficial. The annual dose conversion factor for Radon and progeny was calculated to be between 8.8-58.8 nSv/ (Bq.h/m).

Study of indoor radon concentrations and associated health risks in the five districts of Hazara division, Pakistan

A total of 200 indoor air samples were collected to measure radon concentration levels and its contribution to the mean effective doses during different seasons of the period 2009-2010 at different sites of the five districts of Hazara division, Pakistan. The major portion of the region is mountainous and is full of thick forests which receives heavy snow fall in winter. The need for conducting the present survey relied on the fact that occupants spend their lives in poorly ventilated indoor environments of the region, especially in the winter season when they use wood fire inside their residences. The measurements of indoor air samples were taken with RAD-7, a solid state α-detector. Radon concentrations in the whole region range from 41 Bq m(-3) to 254 Bq m(-3) with a geometric mean of 128 Bq m(-3). Radon progenies were measured with a surface barrier detector through alpha spectroscopy from which the Equilibrium Factor (EF) for radon and Radon Decay Products (RDPs) for the smoke-bearing as well as smoke-free indoor environments were deduced. The respective mean values of EF were calculated as 0.49 ± 0.08 and 0.40 ± 0.07. The mean effective doses from indoor air of Abbottabad, Mansehra, Haripur, Battgram and Kohistan districts were calculated as 3.5 ± 1.2, 3.7 ± 0.7, 3.9 ± 1.0, 3.6 ± 1.1 and 3.9 ± 0.7 mSv a(-1) respectively, with the maximum value of 5.1 ± 1.8 mSv a(-1) in Kohistan district during winter and the minimum value of 2.9 ± 1.0 mSv a(-1) in Abbottabad district during summer. The annual exposure dose to the inhabitants of the locality lies below the upper bound of 10 mSv a(-1), as recommended by ICRP-65, and may not pose any significant threat to the public health.

Measurements of indoor radon concentration levels in Kilis, Osmaniye and Antakya, Turkey during spring season

The fact that 50% of the natural radiation dose to which humans are exposed is caused by radon gas makes indoor radon measurements important. In this study, levels of indoor radon gas were measured in 204 houses in Kilis, Osmaniye and Antakya using passive nuclear track detectors. Cr-39 radon detectors were left in the living rooms of participants’ houses, then analyzed at the Radon Laboratory of Health Physics Department in Cekmece Nuclear Research and Training Center (CANEM) of Atomic Energy Agency of Turkey (TAEK). Average indoor radon activity concentrations for Kilis, Osmaniye and Antakya were 50 Bq/m3 (1.26 mSv/y), 51 Bq/m3 (1.29 mSv/y) and 40 Bq/m3 (1.01 mSv/y), respectively.

In situ measurements of radon levels in water and soil and exhalation rate in areas of Malwa belt of Punjab (India)

Radon concentration levels in water and soil gas from 36 locations pertaining to some areas of Malwa region of Punjab have been measured on an in situ basis using a continuous active radon detector (AlphaGuard, Model – PQ 2000 PRO, Genitron instruments, Germany). Exhalation rate measurements have also been carried out at these places, using a closed-circuit technique. The radon concentrations in soil and water varied from 1.9 to 16.4 kBq m−3 and 5.01 to 11.6 kBq m−3, respectively. The exhalation rate (E Rn) ranged between 7.48 and 35.88 mBq m−2 s−1 with an average value of 18.17 mBq m−2 s−1. Annual dose rates have been calculated for water radon concentrations. The minimum to maximum values of dose rates were found to be 13.42–31.08 μSv y−1. The recorded values of radon concentration in water are within the safe limit of 11 Bq l−1 recommended by the US Environment Protection Agency [National Research Council, Risk Assessment of Radon in Drinking Water (Academy Press, Washington, DC, USA, 1999)]. All measurements were made in similar climatic and environmental conditions to ensure minimal variations in meteorological parameters. An intermediate correlation coefficient (0.5) was observed between radon exhalation rates and soil gas values.

Assessment of indoor radon concentration in phosphate fertilizer warehouses in Nigeria

Indoor radon concentration level was measured in twelve selected phosphate fertilizer warehouses in Nigeria in order to establish potential hazards to persons using such warehouses as offices. The fertilizer warehouses were selected based on the brand of fertilizers stored, size, ventilation pattern and the number of workers in the warehouses during working hours. Electret Ion Chamber Technology (EIC) with the trade name E-PERM TM was employed for the measurement of radon concentration in the warehouses. Average radon concentration in the warehouses range between 33.6 Bq m −3 and 117 Bq m −3with an arithmetic mean of 91.62±5.9 Bq m −3.

Assessment of radon concentration and external gamma radiation level in the environs of Narwapahar uranium mine, India and its radiological significance

In the environs of uranium mining, milling and processing facilities and in the uranium mineralized terrain, a little higher ambient radon concentration and gamma radiation level may be expected in comparison with natural background. The present study gives a brief account of atmospheric radon concentration, gamma absorbed dose rate and radiation dose received by the members of public in the vicinity of Narwapahar uranium mine. The ambient radon concentration in the air in the study area was found to vary from 5 to 107 Bq m−3 with geometric mean of 24 Bq m−3 and geometric standard deviation of 1.74 Bq m−3. The measured gamma absorbed dose rate in air at 1 m above the ground ranged from 87 to 220 nGy h−1 with an overall arithmetic mean of 128 ± 18.5 nGy h−1. The mean annual effective dose received by the members of public from inhalation of radon and its progeny and external gamma exposure was estimated to be 0.32 mSv year−1, which is comparable to other reported values elsewhere.

Shallow circulation groundwater – the main type of water containing hazardous radon concentration

Abstract. The main factors affecting the value of 222Rn activity concentration in groundwater are the emanation coefficient of reservoir rocks (Kem), the content of parent 226Ra in these rocks (q), changes in the volume and flow velocity as well as the mixing of various groundwater components in the circulation system. The highest values of 222Rn activity concentration are recorded in groundwaters flowing towards an intake through strongly cracked reservoir rocks undergoing weathering processes. Because of these facts, waters with hazardous radon concentration levels, i.e. containing more than 100 Bq dm−3 222Rn, could be characterised in the way that follows. They are classified as radon waters, high-radon waters and extreme-radon waters. They belong to shallow circulation systems (at less than a few dozen metres below ground level) and are contemporary infiltration waters, i.e. their underground flow time ranges from several fortnights to a few decades. Because of this, these are usually poorly mineralised waters (often below 0.2–0.5 g dm−3). Their resources are renewable, but also vulnerable to contamination. Waters of this type are usually drawn from private intakes, supplying water to one or at most a few households. Due to an increased risk of developing lung tumours, radon should be removed from such waters when still in the intake. To achieve this aim, appropriate legislation should be introduced in many countries.

Statistical model of quality of radon measurements using electret ion chamber detectors

This paper presents a statistical model for estimating probability, which states that a quality of radon measurements using the electret ion chamber system RM-1 will be accurate. The quality of the electret measurement was modelled as a ratio between the reference radon concentration and values measured under real conditions with varied levels of indoor radon concentration and microclimate indoor conditions. It was stated that the accuracy tolerance of measured values is 20 % of the given reference value. To estimate the uncertainty of the statistical model, the exact confidence limits for the estimated probabilities are computed. The statistical model was confirmed by an independent set of measurements. Moreover, the effect of absolute humidity on the quality estimation of electret detectors are also statistically analysed and discussed. The results of the statistical model confirm that the electret system is robust and suitable for estimation of radon concentration.

Radon and respiratory parameters of some secondary school students in Prizren – Kosovo

The objective of this investigation was the relationship between radon concentration level from indoor areas (classrooms) in some secondary schools of Prizren municipality and eventual consequences of ionizing radiation in the respiratory parameters of secondary school students (N=50, males and females, age 13–15 ).The measurement of radon concentration in indoor area of classrooms from different floors was made with alpha stimulating method using portable apparatus PRM‐145 and the CR‐39 detector of trace that was developed in the “Josef Stefan” Institute in Ljubljana. In the indoor air of classrooms that are located on the basement, the annual average radon concentration (222Rn) varies from 335 – 485 Bq/m3, whereas in the classrooms of other floors between 11–28 Bq/m3. Respiratory parameters were measured by the use of the method of Pulmonary Function Test. Results of the investigation show that compared with the same age group students who study in classrooms with low radon concentration; the students of classrooms with high level of radon concentration show the decreased values of respiratory parameters (tidal volume, vital capacity). The most pronounced changes of these respiratory parameters are emphasized in male students compared to female students.

Indoor exposure of population to radon in the FYR of Macedonia

The authors present the results of a year-long survey of the indoor radon concentration levels in the FYR of Macedonia. A total number of 437 dwellings in eight statistical regions were subject to radon concentration measurements by using CR-39 track detectors. The annual mean indoor radon concentration in each measuring site was estimated from the four individual measurements with 3 months duration. The measuring period was from December 2008 to December 2009. The distribution of the results was nearly log-normal. The arithmetic and geometric mean values of the annual mean value of radon concentration were estimated to be 105 ± 84 and 84*/1.9 Bq m(-3), respectively. The annual effective dose due to indoor exposure to radon in the dwellings was estimated to be 2.1*/1.9 mSv y(-1).

Assessment of external gamma exposure and radon levels in a dwelling constructed with phosphogypsum plates

Phosphogypsum, a fertilizer industry by-product, is being worldwide stockpiled, posing environmental concerns. Since this material contains natural radionuclides in significant concentrations, its use as a building material has radiological implications. In order to confirm the feasibility of the use of a new material mainly composed by phosphogypsum, an experimental house was built, having some of its rooms entirely lined with this material. Measurements of samples of phosphogypsum plates from different origins resulted in values of 0.2 to 2.6 for the external radiation index, thus justifying a more detailed investigation. In this paper, the application of a previously developed computational model to forecast external doses indoors is described. A comprehensive radiological evaluation is being performed, including measurement of the external gamma exposure and radon concentrations in one of the rooms of the house. The results show that the annual increment in the effective dose to an inhabitant of the house will remain below the 1 mSv limit for every reasonable scenario. The radon measurements were carried out over a period of 18 months, in order to determine the long-term average levels of the indoor radon concentrations. The results obtained are below 200 Bq m −3, the recommended investigation level for radon.

Seasonal variation of indoor radon-222 levels in dwellings in Ramallah province and East Jerusalem suburbs, Palestine

This study presents the seasonal variations of indoor radon levels in dwellings located in the Ramallah province and East Jerusalem suburbs, Palestine. The measurements were performed during the summer and winter of the year 2006/2007 using CR-39 solid-state-nuclear-track detectors. The total number of investigated buildings is 75 in summer and 81 in winter. A total number of 142 dosemeters are installed in dwellings for each season for a period of almost 100 d. The radon concentration levels in summer varied from 43 to 192 Bq m(-3) for buildings in the Ramallah province and from 30 to 655 Bq m(-3) for East Jerusalem suburbs. In winter, the radon concentration levels are found to vary from 38 to 375 Bq m(-3) in the Ramallah buildings and from 35 to 984 Bq m(-3) in East Jerusalem suburbs. The obtained results for radon concentration levels in most places are found to be within the accepted international levels.

An Indoor Radon Survey in Three Different Climate Regions in Mexico, and the Influence of Climate in the Obtained Values

In this paper we present the results of a survey of indoor radon concentration levels in Mexico. In order to investigate whether differences in climate translate into significant differences in indoor radon concentrations, the country was divided into three climate regions: the northern semi-desert region, the central semitropical region and the southern tropical region. The survey was carried out using nuclear track methodology. The dosimeters employed for the survey were based on the passive closed-end cup device, developed at the Physics Institute of the National Autonomous University of Mexico, and used PADC as detector material. A well-established protocol for chemically etching and reading the detectors was followed. Average annual temperatures differ between regions (from 15℃ to 28℃) but vary relatively little within each region. Atmospheric temperature is one of the most important factors which need to be considered when carrying out a survey of indoor radon concentrations because temperature largely determines building ventilation habits, and ventilation habits are known to have significant effects on indoor radon concentrations. Other factors, including building construction materials, architectural styles, geological and hydrological characteristics, and seismicity, vary from region to region and within each region. In each of the three regions low levels of indoor radon (from 37 to 179 Bq·m-3) were found.

Comprehensive radon concentration measurements in caves located in the area of Mecsek mountains

Radon concentration has been investigated in nine caves of the Mecsek Mountains, Hungary. Apart from radon concentra­tion, underground temperature and pressure were detected by DATAQUA monitoring devices. Our primary aim was to gain information about boththe radon concentration levels and the convectional systems of these caves in order to study the characteristics of the researcharea. In addition, we intended to detect any differences between the caves either on the basis of the previous measurements or on account of their topo-mor­phological location. Data were comprehensively analyzed in relation to surface temperature and atmospheric pressure. The collected data showed that the caves located in the researcharea have particularly highradon concentrations. The highest values were measured in valley floor-positioned caves whereas the lowest ones in hilltop-positioned caves. In four cases the air convection systems of the studied caves differed from what would have been indicated by their topo-morphological loca­tion. In our study we summarize the convectional laws and uniqueness of the caves investigated.

Radiation Doses Due to Indoor Radon Exposure, Before and After the 2005 Earthquake, in Dwellings of Muzaffarabad and the Jhelum Valley, Azad Kashmir, Pakistan

Radiation doses from indoor radon exposure, before and after the 2005 earthquake, have been assessed from measurements taken in the city of Muzaffarabad and Jhelum valley, Azad Kashmir, Pakistan. Indoor radon concentration was measured in dwellings in Muzaffarabad city and the Jhelum valley after the devastating 2005 earthquake using CR-39 based radon box type detectors which were exposed to indoor radon for 60 days. After processing, the observed track densities were related to the indoor radon concentrations using a calibration factor of 0.0092 tracks cm-2 · hr-1 = 1 Bq m-3 of 222 Rn and compared with already published data obtained before the earthquake. The post-earthquake weighted average indoor radon concentration ranged from 65 Bq m-3 to 398 Bq m-3 for the dwellings of state capital city of Azad Kashmir where pre-earthquake values were in the range of 89 Bq m-3 to 167 Bq m-3. In the Jhelum valley, post-earthquake indoor radon concentrations varied from 81 to 509 Bq m-3 and 64 to 456 Bq m-3 in the bedrooms and kitchens, respectively while pre-earthquake radon concentration for Jhelum valley ranges from 86 to 236 Bq m-3 and 62 to 208 Bq m-3 in the bedrooms and kitchens, respectively. The post earthquake indoor radon concentration levels and hence radiation doses have been found higher than those of pre-earthquake values.

Annual average radon concentration in the show caves of Hungary

Radon can accumulate in underground areas such as show caves. Repairmen and tourist guides working in such caves may thus be exposed to significant radiation doses. Therefore, it is necessary to measure the radon concentration to estimate the exact radiation dose caused by radon. Considering that the radon concentration in caves usually shows significant seasonal fluctuations, the monthly change of radon concentration was studied for 1 year in nine show caves opened to the public in Hungary. Despite the fact that all of the caves were formed in karst rocks, the annual average radon concentration levels were rather different between each other (541–8287 Bq m−3). The significant monthly fluctuation of the radon concentration indicates that the annual average radon concentration in caves can only be accurately obtained by year-long measurements.

Measurement of radon concentration inside houses in Tafila Province, Jordan.

The scope of this paper is to present a brief study related to the investigations we have already made at three districts of Tafila province, which is located in the south part of Jordan and where the most important hot spa and phosphate mines are located. The main concern in these investigations is to measure the indoor radon concentration levels by means of CR-39 detectors installed in randomly selected houses during winter season. The exposure time started from December 2008 and lasted for ninety days. After exposure, the detectors were etched in aKOH solution at 70°C for 8 h. The obtained average values of indoor radon concentration in the three different districts were ranged from 20.45 to 32.41 Bq/m3. It was found out that the Ayma district possesses the highest radon concentration. Meanwhile, the district of Aina Al-Badah possesses the lowest. Key words: Indoor radon, CR-39, passive dosimeter, exposure time.

RADON DOSIMETRY USING CR_39 AS A TRACK DETECTOR

Solid state nuclear detector (CR-39) was used to obtain the concentration level of radon and its daughters, by using (Ra-266) of (10.54mCi) activity. It was employed for radon concentration and potential alpha energy exposure level. It is found increasing in track density with (absorbed dose, WLM, radon concentration in (PCi/liter), and potential alpha energy (PAEC)). The calibration curves were drawn by taking the linear part from the above curves. There is decreasing in absorbed dose with distance from the source. The linear response determine the detector range of (300-3X10 4 Bq/m ), and the calibration factors was obtained for calibration (0.2 0.085 track/ mm 2 per Bq/m 3 ).

Soil gas radon analysis in some areas of Northern Punjab, India

The radon concentration levels in soil samples from 39 locations of Northern Punjab are measured using AlphaGUARD (PQ 2000 PRO Model) of Genitron instruments, Germany. The radon concentration in soil varies from 0.3 to 35.8 kBq/l. The minimum value of radon is observed in Talwandi Choudhrian and is maximum for Nushera Dhala. The soil gas radon is correlated with soil temperature, pressure, and humidity to observe the effect of these parameters on radon release. The soil gas radon values in the study area are compared with that obtained in groundwater. The results are also compared with the available radon data for other parts of Punjab and Himachal Pradesh.