Environmental Radon Research Articles

Bulk Etch Rate of LR 115 Polymeric Radon Detector

In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this SSNTD, were determined by measuring the average initial thickness (before etching) and residual thickness after 80 to 135 minutes chemical etching in the standard conditions, using an electronic comparator. These results allowed the calculation of the bulk etch rate of this detector in a simple way. The mean value obtained is (3.21 ± 0.21) μm/h. This value is in close agreement with those reported by different authors. It is an important parameter for alpha track counting on the sensitive surface of this polymeric detector after chemical etching because track density depends extremely on its removed layer. This SSNTD was then used for environmental radon gas monitoring in Côte d’Ivoire.

Incidence and risk factors for feline lymphoma in UK primary-care practice.

ObjectivesThe study aimed to estimate the incidence and prevalence of feline lymphoma in cats attending primary‐care practices across the UK and to identify patient‐based and environmental (radon and pesticide exposure) risk factors.Materials and MethodsCase records from the VetCompass programme from primary‐care veterinary practices in the UK were searched for a diagnosis of lymphoma in cats in 2016. Cases were required to have had an external laboratory confirmed diagnosis based on cytology and/or histopathology. A nested case–control study design was used to identify risk factors for lymphoma using multivariable logistic regression.ResultsFrom a cohort of 562,446 cats under veterinary care at VetCompass participating practices in 2016, a total of 271 lymphoma cases were identified (prevalence: 48/100,000, 95% confidence interval (CI) 44 to 56/100,000; incidence 32/100,000, 95% CI 26 to 35/100,000). There were 180 incident lymphoma cases and 803 controls, all aged 2 years and older. Male (odds ratio (OR) 1.7, 95% CI 1.2 to 2.4), insured (OR 3.6, 95% CI 2.3 to 5.6) and older cats (compared to cats 2 to <5 years, OR 5.0, 95% CI 2.8 to 8.8) were associated with increased odds of lymphoma diagnosis. Vaccinated cats were associated with decreased odds (OR 0.7, 95% CI 0.5 to 1.0) compared to unvaccinated cats, although the type of vaccination received was not statistically significant. Breed and environmental factors studied were not associated with a diagnosis of lymphoma.Clinical SignificanceThis is the first study to estimate the frequency and report risk factors for lymphoma in cats attending UK primary‐care practice.

Novel panorama megasize environmental radon monitor

A novel panorama megasize environmental radon monitor (MS-ERM) is introduced using megasize polycarbonate track detector (PCTD) having some activated carbon fabric (ACF) layers on some locations. The MS-ERM is processed by panorama single-cell megasize electrochemical etching image processing system. The MS-ERM is 75 × 35 cm2 large (~1000 μm thick) which can monitor and map large environmental areas. Circular ACF layers placed on the MS-ERM can adsorb radon on its carbon active sites and enhance PCTD response by an amplification factor of ~1.5 times. The panorama MS-ERM is position sensitive resembling infinite number of single detectors assembled for providing data matrix of radon concentrations of large environmental area. A specially-designed radon chamber was constructed with 226Ra containing soil at its base for exposing MS-ERMs. Radon concentration is maximum over the radon source and decreases to a constant 222Rn concentration from few centimeters over the source up to top of the radon chamber.

A new graph of soil Rn-gas transport: Radon-rose plot

Soil radon gas movement depends on soil geology, environmental thermodynamic parameters and, micro-seismic telluric activity. Mapping radon time dependent concentration at the relaxation depth in a selected area, provide transport direction in a seismically high-risk region. Nuclear track methodology is employed to determine main gradient vector for radon transport. Applying the gradient definition, a “radon rose” graph is constructed from which prone area can be promptly identified. Results show that short time interval, Rn-transport direction may change unpredictably, however, the length of each "spoke" around the circle provides information on the soil Rn-gas probable shifts towards or from a direction per time interval. The new graph is a novelty and provide improved approach for environmental protection and radon dosimetry.

Ecological level analysis of primary lung tumors in dogs and cats and environmental radon activity.

BackgroundEpidemiologic studies suggest residential radon exposure might increase the risk of primary lung cancer in people, but these studies are limited by subject mobility. This limitation might be overcome by evaluating the association in pets.HypothesisPrimary pulmonary neoplasia (PPN) rate is higher in dogs and cats residing in counties with a high radon exposure risk (Environmental Protection Agency [EPA] zone 1) compared to zones 2 (moderate radon exposure risk) and 3 (low radon exposure risk).AnimalsSix hundred ninety client‐owned dogs and 205 client‐owned cats with PPN.MethodsRetrospective review of medical records at 10 veterinary colleges identified dogs and cats diagnosed with PPN between 2010 and 2015. Each patient's radon exposure was determined by matching the patient's zip code with published county radon exposure risk. County level PPN rates were calculated using the average annual county cat and dog populations. The PPN counts per 100 000 dog/cat years at risk (PPN rates) were compared across radon zones for each species.ResultsThe PPN rate ratio in counties in high radon zone (1) was approximately 2‐fold higher than in counties in lower radon zones for dogs (rate ratio zone 1 to 2, 2.49; 95% confidence interval [CI], 1.56‐4.00; rate ratio zone 1 to 3, 2.29; 95% CI, 1.46‐3.59) and cats (rate ratio zone 1 to 2, 2.13; 95% CI, 0.95‐4.79; zone 1 to 3, 1.81; 95% CI, 0.9‐3.61).Conclusions and Clinical ImportanceExposure to household radon might play a role in development of PPN in dogs and cats.

Radiation Protection Legislation and Sustainable Development of a Rural Green Tuff Village of Ischia Island

Radiological risk affects the quality of the environment in buildings since population and workers can be potentially exposed to high levels of radiation. Radon gas emanating from both subsoil and building materials represents the most important source of radiation exposure for people. This study investigates the sustainability concept of a small rural village of Ischia Island, named Ciglio, in relation to radiation protection legislation concerning the radiological risk for workers. Radon activity concentration was measured in typical green-tuff dwellings and in water samples collected from a local waterfall E-Perm devices. Moreover, for green tuff as building material, the radon emanation coefficient was calculated by gamma spectroscopy. The results highlight the importance of performing environmental radon monitoring and investigating the radon content of building materials, especially in geographical areas characterized by traditional use of typical stones for constructions. In conclusion, the sustainable development of rural buildings is possible if the radiological risk for inhabitants and workers is assessed in line with the national radiation protection legislation.

A discussion on the potential impact of residential radon exposure on the quality of exposure and risk assessment for former uranium miners

Epidemiological evidence of lung cancer risk from radon is based mainly on studies of underground miners where occupational exposures were, historically, relatively high in comparison to residential indoor exposure. However, radiation protection measures have caused radon levels in uranium mines to decrease significantly in more recent periods. Miners’ occupational exposure is limited to their working years while they are exposed to environmental radon at home over their entire lifetime. Even during their limited working years, workers spend much more time at home than in workplaces. The biological effect of radon in mines cannot be distinguished from the biological effect of residential radon. Therefore, for an exposure–risk relationship study of former uranium miners, excess radon-induced lung cancer cases should be related to the combined radon exposure cumulated in workplaces and at homes in excess of the radon exposure of the reference population. This is especially important when residential radon levels differ or vary significantly between miners and the reference population over the course of extended follow-up years. This paper reviews some recent studies on former uranium miners, shares what seems controversial to the author and wonders whether lifetime exposure at home to widely varying radon concentrations can actually impact the quality of exposure assessment, and hence impact the results of the exposure–risk relationship.

Low dose environmental radon exposure and breast tumor gene expression

BackgroundThe International Agency for Research on Cancer classified radon and its decay-products as Group-1-human-carcinogens, and with the current knowledge they are linked specifically to lung cancer. Biokinetic models predict that radon could deliver a carcinogenic dose to breast tissue. Our previous work suggested that low-dose radon was associated with estrogen-receptor (ER)-negative breast cancer risk. However, there is limited research to examine the role of radon in breast cancer biology at the tissue level. We aim to understand molecular pathways linking radon exposure with breast cancer biology using transcriptome-wide-gene-expression from breast tumor and normal-adjacent tissues.MethodsOur study included 943 women diagnosed with breast cancer from the Nurses’ Health Study (NHS) and NHSII. We estimated cumulative radon concentration for each participant up-to the year of breast cancer diagnosis by linking residential addresses with a radon exposure model. Transcriptome-wide-gene-expression was measured with the Affymetrix-Glue-Human-Transcriptome-Array-3.0 and Human-Transcriptome-Array-2.0. We performed covariate-adjusted linear-regression for individual genes and further employed pathway-analysis. All analyses were conducted separately for tumor and normal-adjacent samples and by ER-status.ResultsNo individual gene was associated with cumulative radon exposure in ER-positive tumor, ER-negative tumor, or ER-negative normal-adjacent tissues at FDR < 5%. In ER-positive normal-adjacent samples, PLCH2—reached transcriptome-wide-significance (FDR < 5%). Gene-set-enrichment-analyses identified 2-upregulated pathways (MAPK signaling and phosphocholine biosynthesis) enriched at FDR < 25% in ER-negative tumors and normal-adjacent tissues, and both pathways have been previously reported to play key roles in ionizing radiation induced tumorigenesis in experimental settings.ConclusionOur findings provide insights into the molecular pathways of radon exposure that may influence breast cancer etiology.

Evaluation and mitigation of trace 210Pb contamination on copper surfaces

Clean materials are required to construct and operate many low-background physics experiments. High-purity copper has found broad use because of its physical properties and availability. In this paper, we describe methods to assay and mitigate 210Pb contamination on copper surfaces, such as from exposure to environmental radon or coming from bulk impurities. We evaluated the efficacy of wet etching on commercial samples and observed that 210Po contamination from the copper bulk does not readily pass into solution. During the etch, the polonium appears to trap at the copper–etchant boundary, such that it is effectively concentrated at the copper surface. We observed a different behavior for 210Pb; high-sensitivity measurements of the alpha emissivity versus time indicate the lowest level of 210Pb contamination ever reported for a commercial copper surface: 0±12nBq/cm2 (1σ). Additionally, we have demonstrated the effectiveness of mitigating trace 210Pb and 210Po surface backgrounds using custom, high-purity electroplating techniques. These approaches were evaluated utilizing assays performed with an XIA UltraLo-1800 alpha spectrometer.

Environmental radon, its exhalation rates and activity concentration of 226Ra, 232Th, and 40kK in Northern India

Human beings are constantly exposed to radioactivity in the environment. As they are major sources of harmful radiation, radionuclides found in the atmosphere might result in a substantial potential risk to living beings. On the Earth's surface, the radioactive elements uranium and radium are naturally present, contributing to radon and thoron gases in the indoor as well as outdoor climate, soil and water. Radon is one of the most important toxins that, after cigarette smoking, is the second most common cause of generating lung cancer. Due to these health-related concerns, a lot of work has been undertaken by numerous research organizations to determine their levels at different locations throughout the world. This paper is an attempt to comprehensively report with different techniques all those studies being carried out in this part of India so that a current assessment of the indoor radon levels should be available for further work in this field. Six northern Indian states, viz. Punjab, Haryana, Himachal Pradesh, Rajasthan , Uttar Pradesh and Uttarakhand are considered for this examination. This study also provides data on exhalation rates and activity concentration of natural radionuclides (226Ra, 232Th, and 40K) present in these states.

Geographic distribution and environmental risk factors of lymphoma in dogs under primary-care in the UK.

To integrate external data sources with VetCompass postcode data to explore the spatial distribution and examine potential associations with environmental risk factors in dogs diagnosed with lymphoma at primary care veterinary practices. Cases of lymphoma were identified from electronic patient records of 455,553 dogs under primary veterinary care during 2013 in the UK. Cases were defined as either laboratory-confirmed or non-laboratory-confirmed. Disease maps at the postcode-district level were used to define the geographic distribution of lymphoma incidence and spatial clustering was explored. Environmental risk factors from external data sources were transferred to a compatible format and logistic regression modelling was used to examine associations between environmental herbicide, fungicide and radon concentrations with lymphoma. From the denominator population of 455,553 dogs, 279 lymphoma cases (187 with laboratory confirmation and 93 without) were identified. Heterogeneous geographic variation was observed with weak evidence of clustering around London and the south-west of England. Herbicide and fungicide exposures were weakly associated with a diagnosis of lymphoma in the univariable analysis. After accounting for the age at diagnosis and breed in the multivariable analysis, herbicide exposure was associated with a diagnosis of lymphoma. The heterogeneous distribution of lymphoma in UK dogs provides further evidence for geographic variation of lymphoma, perhaps in part associated with underlying environmental risk factors. The results suggest an association between environmental herbicide and canine lymphoma.

Detection and Analysis of the Concentration of Radioactive Radon in the Construction Environment of a University

Radioactive radon is an important hazard in indoor air environments. In order to study the concentration of radon in the building environment, this paper tests the content of cockroaches in a university dormitory, teaching building and auxiliary room through experiments. And the experimental results are analyzed. The results show that: In the built environment, the closer the soil is to the foundation, the higher the concentration of radioactive radon, and the effect of temperature and humidity on the concentration of radioactive radon is very small.

Constructing Environmental Radon Gas Detector and Measuring Concentration in Residential Buildings

Background: From the health physics perspective, radon gas is one of the most dangerous gases in residential and business environments. According to the WHO (World Health Organization), radon gas is considered the second cause of lung cancer in societies after smoking. Methods: In this study, the environmental radon gas has been measured using a built radon gas detector on a specific preamplifier circuit and then the perceived results were compared with an Alpha-Guard detector. Specific activity and output ratio on radon concentration in air were measured on three different floors of a residential building covered by different materials. Results: The results showed a good correlation between the outputs and data gathered by the Alpha-Guard. In underground covered by plaster and cement, the detector responses showed approximately double amounts in comparison with the ground floor. The different covered places revealed dissimilar responses, so that the screened granite had greater amounts by 347 ± 37 Bq/m3. Besides, the minimum response was revealed on the first floor using Alpha-Guard by 47 ± 6 Bq/m3. Results confirmed that on each floor, which has a good ventilation system, the exposure due to the radon isotopes can be immensely reduced. Conclusions: This system can also be used to measure the radon concentration changes in the environment and groundwater.

A low-cost experiment to identify variations in the concentration of environmental radon

Radon is a dangerous radioactive gas that is always present in the environment. It is important that students and society in general are aware of radon as a health hazard. This study describes a simple experiment to measure the variations of radon gas concentration outdoors. We compared the concentration of radon gas in the environment in dry and wet weather conditions and at different times of day. The results show that outdoor radon concentrations are significantly lower, by as much as 50%, during cloudy and rainy conditions.

A NEW BACKGROUND SUBTRACTION METHOD FOR ASSESSING PUBLIC RADIATION EXPOSURE DUE TO RADON TRANSPORT FROM A URANIUM MINE.

Environmental radon progeny concentration data for the Ranger mine in the Australian wet-dry tropics were analysed. Concentrations in air at public receptor locations correlated with wind direction and were generally higher when the wind had a southerly component. The regional setting suggested that correlations were due to geography rather than the mine. The line of best fit to the radon progeny data when plotted against angle of wind direction was used to estimate background concentrations when the wind was from the direction of the mine. This differed from the standard approach of averaging concentrations when the wind was not from the direction of the mine. Background concentrations in mine-related wind directions using the line of best fit approach were generally higher than those predicted from averaging, as mine-related wind directions included a southerly component. Estimates of mine-related doses to the public were generally lower as a result.

ANNUAL EFFECTIVE DOSE ASSESSMENT DUE TO RADON AND THORON PROGENIES IN DWELLINGS OF KILIMAMBOGO, KENYA.

Human beings are continuously exposed to ionising radiation originating from natural or artificial sources. Uranium-238 and Thorium-232 found in building materials are important sources of radon and thoron in the indoor environment. The concentration levels of radon, thoron and thoron progeny were measured in mud-walled, metallic or iron sheet-walled and stone-walled modern houses in Kilimambogo region, Kenya for 3 months. Radon and thoron concentration levels were measured using passive radon-thoron discriminative monitors (RADUET), while thoron progeny concentrations as the equilibrium equivalent thoron concentration (EETC) were measured using thoron progeny monitors. The mean radon concentration levels in mud, metallic and stone-walled dwellings were 67 ± 11, 60 ± 10 and 75 ± 10 Bq m-3, respectively. The mean thoron concentration levels in the corresponding dwellings were 195 ± 36, 71 ± 24 and 161 ± 31 Bq m-3, respectively, while EETCs were 12 ± 2, 3 ± 1 and 7 ± 1 Bq m-3, respectively. The annual effective doses for radon were 1.3 ± 0.2, 1.1 ± 0.1 and 1.4 ± 0.2 mSv y-1 in mud, metallic and stone-walled houses while those from thoron estimated from EETC were 2.4 ± 0.4, 0.5 ± 0.1 and 1.5 ± 0.2 mSv y-1 in the corresponding houses, respectively.

Environmental Radio‐Toxins as Possible Radio‐biomarkers for Diseases of the CNS

A hypothesis is presented identifying environmental radon (EnRn) progeny as a radio‐biomarker of use in studies of the brain and central nervous system (CNS) diseases such as Alzheimer's (AD) and Parkinson's (PD). The long‐lived environmental radon progeny, Pb‐210/Po‐210, in air and soil is a common radio‐biomarker in plants and animals. Hydrocarbon combustion in power plants and internal combustion engines produce copious quantities of ultrafine carbon particles that entrain heavy metals such as Pb‐210 found in air of the combustion process. The UFP's laden with Pb‐210 are readily taken up in the lungs and transported by the blood throughout the body including the brain and CNS. The more numerous small UFP's (&lt;10nm) can be transferred across the blood‐brain and cellular barriers into cells where Pb‐210 is permanently deposited. The Pb+2 ions can mimic Ca+2 in brain and CNS cellular action potential systems providing a pathway into the cells and producing deleterious biochemical effects, additionally with radioactive Pb‐210 there are cellular radiation effects. Within the context of the proposed hypothesis data of diseased brain tissues containing Pb‐210/Po‐210 showed selective deposition in the brain proteins in AD and brain lipids in PD, with increased Po‐210 in MS colon tissueSupport or Funding InformationThis abstract is an end result of over 40 years of collaborative studies of environment radon progeny in humans. Collaboration among scientists from academia, government and private industry is noted.The support programs are too numerous to mention, but have been recognized in peer‐reviewed publications associated with the work.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Measurement of Radium Concentration and Radon Exhalation Rates of Soil Samples Collected from Selected Area of Aden Governorate, Yemen, Using Plastic Track Detectors

Radon exhalation rate from soil is one of the most important factors for evaluation of the environmental radon level. Solid State Nuclear Track Detectors (CR-39) has been widely used for the study of different aspects of radon emission from soil and others. In this paper, we are presenting the results of radon concentration, its exhalation rate and radium content in soil samples collected from different locations of northern part of Aden governorate, south of Yemen. The outdoor radon levels concentrations were found to vary from 264.59Bq m-3 to 539.72Bq m-3 with a mean value of 369.29Bq m-3. The radon exhalation rate in terms of area and in terms of mass were found to vary from 460.08 mBq.m-2.h-1to 938.47mBq.m-2.h-1with a mean value of 642.12mBq.m-2.h-1 and from 25.99mBq.m-2.h-1 to 53.02mBqkg-1.h-1 with a mean value of 36.28 mBqkg-1.h-1. The results of effective radium concentrations in these sites were found to vary from 3.44 Bqkg-1 to 7.01 Bqkg-1 with a mean value of 4.80Bqkg-1. The working level varied from 4.54mWL to 9.26mWL with a mean value of 6.34mWL. The radon annual effective dose was varied from 0.049mSvy-1 to 0.100mSvy-1 with a mean value of (0.068±0.18) mSvy-1 for outdoor and from 0.20mSvy-1 to 0.40mSvy-1 with a mean value of 0.27mSvy-1 for indoor. The results indicate that the soil is quite safe for occupancies and to be used as building materials.

Micronuclei frequency in peripheral blood lymphocytes and levels of anti-p53 autoantibodies in serum of residents of Kowary city regions (Poland) with elevated indoor concentrations of radon

IntroductionNinety four residents of Kowary city (Poland) have been investigated for environmental radon exposure that ranged from 0.24 WLM to 9.6 WLM (activity concentration range: 35–2700 Bq/m3). Kowary was chosen because of uranium mineralisation in its close vicinity. MethodWhole population studied was divided into two groups: exposed to low radon activity concentrations resulting in the exposure of ≤0.55 WLM (value corresponding to the exposure to 100 Bq/m3 during whole year), and exposed to high radon activity concentration (>0.55 WLM). In the two groups two selected biomarkers in blood were assessed: the cytokinesis-block micronucleus assay (CBMN) on peripheral blood lymphocytes (PBL), and the levels of anti-p53 antibodies in serum measured because some data indicate increased expression of the antibodies in individuals after exposure to DNA damaging agents including radon. The potential confounding factors known to influence micronuclei (MN) frequency were also measured in serum: vitamin B12, folic acid, as well as total calcium. ResultsIn the present study no significant correlation was found between MN frequency in PBL and radon exposure. Among all persons investigated only 11 had detectable levels of the anti-p53 antibodies, whereas only 3 persons had positive result. Therefore, the group was too small to perform any meaningful statistical analysis and to conclude on any association. Cigarette smoking did not significantly influence the number of MN. There was a significant positive correlation observed between MN frequency and age, as well as higher MN frequency was detected in women. ConclusionThe problem of the radon exposure is still unresolved and needs further studies on bigger human cohorts in order to search for more sensitive biomarkers.

Concentration and duration dependence of a new prototype polycarbonate/activated-carbon fabric individual and environmental radon monitor

The basic design of new multi-purpose polycarbonate track detector (PCTD)/activated-carbon-fabric (ACF) detector for radon monitoring in particular for parametric studies has been recently self-invented in our laboratory by enhancing PCTD's sensitivity by using the ACF adsorptive layer as external alpha radiator. The PCTD/ACF monitor basically consists of a PCTD; half bare and half covered with ACF in order to adsorb radon on its carbon active sites. From parameters studied, radon concentration and exposure duration were discovered to be the most important parameters affecting the monitor's sensitivity enhancement. An amplification factor (AF), defined as ratio of net PCTD/ACF to PCTD/bare alpha track density responses after background track density subtraction, was found being highly dependent on the two stated parameters. The AF versus duration response is flat with a value ∼1.5 constant up to 32 days in ∼180±20 Bq.m−3 radon environment and also flat with a constant value ∼7.5 up to 8 days in ∼25±1.1 kBq.m−3 radon environment after which the AF decreases down to ∼3.0 up to 32 days exposure. This phenomenon seems be due to full occupancy of radon atoms on the ACF active sites at high concentrations with an equilibrium between adsorption and desorption processes. The latter significantly dominates after 8 days in ∼25±1.1 kBq.m−3 environment leaving behind non-active sites requiring regeneration. The prototype monitor developed can be applied to normal level individual and/or environmental radon monitoring for an extended period of time but to high radon concentrations for short-term such as a week as a “grab sampler” with a high prospect for determination of radon equilibrium factor with its progeny in the radon environment under measurement. The actual radon monitor and its parametric studies are under further development.