Investigation of the Performance of Various Low-Cost Radon Monitors under Variable Environmental Conditions.

A comparison of low-cost radon monitors was conducted at the Laboratory of Natural Radiation (LNR). The monitors we evaluated were EcoQube, RadonEye, RadonEye Plus2, Spirit, ViewPlus, ViewRadon and WavePlus. An AlphaGUARD monitor calibrated at the Laboratory of Environmental Radioactivity of the University of Cantabria (LaRUC), accredited for testing and calibration according to ISO/IEC 17025, provided the reference value of radon concentration. The temporal stability of the monitors was studied, obtaining a percentage of missing records ranged from 1% to 19% of the data. The main technical characteristics studied were temporal stability, measurement ranges, accuracy, correlation and response time. The main results show that the measurement ranges align with those specified by their manufacturers, with percentage differences with respect to the reference monitor of between 5% and 16%. The diversity found for response time is remarkable, with values ranging from 1 to 15 h, with Pearson correlation factors between 0.63 and 0.90.

Clinical and Economic Impact of Wound Care Using a Polyurethane Foam Multilayer Dressing.

OBJECTIVE: To study the impact of a newly introduced dressing on efficiency and quality of care in routine clinical practice in a Spanish community setting. DESIGN AND SETTING: An ambispective multicenter observational study was conducted in 24 primary care centers and 6 nursing homes in 4 different Spanish regions. The study was carried out between November 2017 and March 2019. PATIENTS AND INTERVENTION: A total of 128 wounds in 94 patients (primary care, n = 79; nursing home, n = 15) were analyzed before and 4 weeks after switching to the study dressing. OUTCOME MEASURES: Frequency of dressing changes; secondary outcomes were change in the mean wound area and weekly cost and patient and provider satisfaction. MAIN RESULTS: The mean number of dressing changes was significantly reduced with the study dressing from 3.14 ± 1.77 changes per week to 1.66 ± 0.87 (P < .001), a 47.1% reduction in frequency. Wound area significantly reduced from 9.90 ± 19.62 cm to 7.10 ± 24.33 cm. In addition, a 58.7% reduction in weekly costs was achieved with the intervention. Patients and providers agreed that their satisfaction with wound care improved. CONCLUSIONS: The use of the study dressing in routine clinical practice could lead to a major improvement in both efficiency and quality of wound care. Its use could reduce wound care-related costs through improvements in healing and a reduced frequency of dressing changes. It also enhanced the wound care experience from the perspective of both patients and providers.

The path from geology to indoor radon.

It is generally accepted that radon emission is strongly influenced by the geological characteristics of the bedrock. However, transport in-soil and entry paths indoors are defined by other factors such as permeability, building and architectural features, ventilation, occupation patterns, etc. The purpose of this paper is to analyze the contribution of each parameter, from natural to man-made, on the radon accumulation indoors and to assess potential patterns, based on 100 case studies in Romania. The study pointed out that the geological foundation can provide a reasonable explanation for the majority of the values recorded in both soil and indoor air. Results also showed that older houses, built with earth-based materials, are highly permeable to soil radon. Energy-efficient houses, on the other hand, have a tendency to disregard the radon potential of the geological foundation, causing a higher predisposition to radon accumulation indoors and decreasing the general indoor air quality.

Variations in radon dosimetry under different assessment approaches in the Altamira Cave.

The atmosphere of caves is a special environment where it is necessary to take into account some particular characteristics when assessing the radon dose. The equilibrium factor (F) between radon and its progeny, and especially its unattached fraction (f p), is a key parameter in radon dose evaluation. In order to consider the specific features of the atmosphere in the Altamira Cave, the radon and particle concentrations have been measured. The mean annual radon concentration inside the cave over the period 2013-2019 is around 3500 Bq m-3 with a standard deviation of 1833 Bq m-3 and this exhibits seasonal variations. This value surpasses all international (WHO, IAEA, ICRP) upper action and reference levels (occupational and non-occupational). Dose rate levels expressed in µSv h-1 were estimated for four different equilibrium scenarios between radon and its progeny 218Po, 214Pb, 214Bi and 214Po. The most recent dose conversion factors have been used and the contribution made to the dose by the unattached fraction of radon progeny f p has been also assessed from the particle concentration. The results suggest that the mean annual dose levels show variations of up to 500% due to the range of F and the f p considered in this study. Given the high radon concentrations usually found in show caves, the best way to reduce this variability and its associated uncertainty in dose assessment is to conduct specific studies aimed at determining both F and f p.

Performance of radon monitors in a purpose-built radon chamber.

The purpose of this paper is to benchmark several different radon monitors, by quantifying their accuracy and response time. Radon monitors with different characteristics were tested in a purpose-built radon chamber under reference conditions. The radon concentration in the chamber was controlled and maintained at a stable radon concentration of (2648 ± 85) Bq m-3 to evaluate the accuracy and precision of these monitors. The response time of the monitors was analysed for two time intervals. To assess the response time of the monitors, radon concentration was varied from a theoretical value of 0-6441 Bq m-3 and then from 6441 to 2648 Bq m-3. The results from this study show that general purpose radon monitors are less accurate than those used by radon testing service providers and the research community. All monitors tested reported a mean radon concentration within the ±10% of the reference detector value at the radon equilibrium concentration. Different response time analysis methods were proposed and discussed, and for the particular time intervals analysed, response time was found to be slower for those radon monitors intended for general purpose applications.

[Nutritional, bone and body composition assessment of patients with knee and hip arthroplasty]. / Valoración nutricional, ósea y de composición corporal de pacientes con artroplastia de rodilla y cadera.

Introduction: Introduction: malnutrition, both due to deficiency and excess of nutrients, correlates to the morbidity of the surgical patient. Objectives: to analyze the nutritional status, body composition and bone health of patients undergoing elective knee and hip arthroplasty. Methods: an observational cross-sectional study was carried out evaluating patients undergoing hip and knee replacement surgery from February to September 2019. The Malnutrition Universal Screening Tool (MUST), anthropometry, hand-grip dynamometry, bone densitometry, lumbar spine X-ray and bioimpedance analysis were performed. Results: eighty-six patients (61.6 % women) were evaluated, with a mean age of 69.5 ± 9.5 years. The mean body mass index (BMI) was 31.3 ± 4.5. According to MUST, 21.3 % were at risk of malnutrition; 16.9 % had decreased triceps skinfold with respect to p50 and 20 % had a pathological hand-grip dynamometry. In 91.4 %, vitamin D was < 30 pg/ml. In the bioimpedanciometry, the women presented significantly decreased muscle mass values. Age was correlated with a lower presence of fat-free mass, total and appendicular muscle mass. In those over 65 years of age, 52.6 % of men vs 14.3 % of women had a decreased muscle mass index; 58.5 % had low bone mineral density. We observed vertebral bone collapses in 13.9 %. Conclusion: there is a high prevalence of obesity in patients who are candidates for arthroplasty and this does not exclude the existence of a risk of malnutrition. They may also have decreased muscle mass and strength. Nutritional education and physical exercise recommendations are essential in order to optimize nutritional status for surgery.

Introducción: Introducción: la malnutrición tanto por defecto como por exceso de nutrientes se relaciona con la morbilidad del paciente quirúrgico. Objetivos: analizar el estado nutricional, la composición corporal y la salud ósea de pacientes sometidos a artroplastia electiva de rodilla y cadera Método: se realiza un estudio transversal observacional evaluando pacientes que ingresan para cirugía de prótesis de cadera y rodilla de febrero a septiembre de 2019. Al ingreso, se realizan Malnutrition Universal Screening Tool (MUST), antropometría, dinamometría manual, densitometría ósea, radiografía de columna lumbar y bioimpedanciometría. Resultados: se evaluó a 86 pacientes (61,6 % mujeres), con edad media de 69,5 ± 9,5 años. El índice de masa corporal (IMC) medio fue de 31,3 ± 4,5. Según MUST, el 21,3 % estaba en riesgo de desnutrición. El 16,9 % tenía disminuido el pliegue tricipital respecto al p50 y el 20 % tenía una dinamometría manual patológica. En el 91,4 % la vitamina D fue < 30 pg/ml. En la bioimpedanciometría, las mujeres presentaban valores de masa muscular significativamente disminuidos. La edad se correlacionó con menor presencia de masa libre de grasa, masa muscular total y apendicular. En mayores de 65 años, el 52,6 % de varones vs. 14,3 % de mujeres presentaban un índice de masa muscular disminuido. El 58,5 % tenía densidad mineral ósea baja. Objetivamos aplastamientos vertebrales en el 13,9 %. Conclusiones: existe una alta prevalencia de obesidad en pacientes candidatos a artroplastia y esto no excluye la existencia de riesgo de desnutrición. Además, pueden presentar disminución de masa y fuerza muscular. Es fundamental la educación nutricional y recomendaciones de ejercicio físico de cara a optimizar el estado nutricional para cirugía.

Use of Radon and CO2 for the Identification and Analysis of Short-Term Fluctuations in the Ventilation of the Polychrome Room Inside the Altamira Cave.

A study is presented on rapid episodes of air exchange in the Polychrome Room of the Altamira Cave (Cantabria, Spain) using continuous monitoring of radon and CO2 tracer gases, as well as environmental parameters such as internal and external air temperature. For this, criteria have been developed to carry out an inventory of these types of events during the 2015-2020 period. Most of the degassing-recharging events occur over several hours or days, especially during spring and autumn. This means that the room can be significantly ventilated during these short periods of time, posing an exchange of energy and matter with potential impact in the preservation of the rock art present inside. In addition, the hypothesis that temperature gradients between the internal and external atmosphere is one of the main factors that induces degassing has been tested. To this end, correlation analysis has been carried out between the different magnitudes involved in this study, such as radon and CO2 concentrations, and air temperature gradients. A total of 37 degassing-recharging events have been analyzed for the 5 year studied period. The distribution of the duration of the events have been described, as well as that of the correlations between the degassing and recharge stages of each event, showing significant values of r coefficients for the correlation with temperature gradients between the internal and external atmosphere.

Intercomparison of Radon Flux Monitors at Low and at High Radium Content Areas under Field Conditions.

Interlaboratory exercises are a good tool to compare the response of different systems to the same quantity and to identify possible inconsistencies between them. One of the main goals of the EMPIR 19ENV01 traceRadon project is to harmonize radon flux measurements based on different systems and methodologies. In the framework of the traceRadon Project, two radon flux intercomparison campaigns were carried out in October 2021 at high and at low radon source areas. Four institutions participated in the field intercomparison exercises with their own systems. Every system was based on a specific radon monitor (diffusion or pump mode) and an accumulation chamber (with manual or automatic opening). Radon fluxes were calculated by each participant using both exponential and linear fittings of the radon activity concentration measured over time within the accumulation chambers. The results of this study show mainly: (i) the exponential approach is not advisable due to the variability of the radon flux and the leakage of the systems during long-time measurements; (ii) the linear approach should be applied to minimize the measurement period in agreement with the time response and sensitivity of the monitors; (iii) radon flux measured at high radon source areas (radium content of about 800 Bq kg-1) risks being underestimated because of the influence of advective effects; (iv) radon flux measured at low radon source areas (radium content of about 30 Bq kg-1) may present large uncertainties if sensitive radon monitors with pump mode are not used.

General model for estimation of indoor radon concentration dynamics.

A known relationship exists between high radon concentrations and lung cancer, and therefore, the indoor radon quantification is important, and it is beneficial to have a model to estimate indoor concentration. The work is focused on the development of an INDORAD (INDOor RAdon Dynamic) model for estimation of indoor radon dynamics, with time-dependent meteorological parameters and adjustable soil and building properties being considered. This model is based on a systemic approach, where the flows of material between compartments are considered, without a spatial resolution. This approach allowed to simplify the mathematical processing and enabled to consider together all known sources of indoor radon. The developed model was put in use in a laboratory building where soil constitutes major source of radon. The results (radon concentrations) from the model were compared to an existing data set from Saelices el Chico in a soil with high concentration of 226Ra. The outcome of the validation implies that INDORAD could predict radon concentrations satisfactorily. Suggestions for future updates of the model to improve indoor radon estimations are provided.

A New Methodology for Defining Radon Priority Areas in Spain.

One of the requirements of EU-BSS (European Basic Safety Standards) is the design and implementation of a National Radon Action Plan in the member states. This should define, as accurately as possible, areas of risk for the presence of radon gas (222Rn) in homes and workplaces. The concept used by the Spanish Nuclear Safety Council (CSN), the body responsible for nuclear safety and radiation protection in Spain, to identify "radon priority areas" is that of radon potential. This paper establishes a different methodology from that used by the CSN, using the same study variables (indoor radon measurements, gamma radiation exposure data, and geological information) to prepare a radon potential map that improves the definition of the areas potentially exposed to radon in Spain. The main advantage of this methodology is that by using simple data processing the definition of these areas is improved. In addition, the application of this methodology can improve the delimitation of radon priority areas and can be applied within the cartographic system used by the European Commission-Joint Research Center (EC-JRC) in the representation of different environmental parameters.

The Metrological Traceability, Performance and Precision of European Radon Calibration Facilities.

An interlaboratory comparison for European radon calibration facilities was conducted to evaluate the establishment of a harmonized quality level for the activity concentration of radon in air and to demonstrate the performance of the facilities when calibrating measurement instruments for radon. Fifteen calibration facilities from 13 different European countries participated. They represented different levels in the metrological hierarchy: national metrology institutes and designated institutes, national authorities for radiation protection and participants from universities. The interlaboratory comparison was conducted by the German Federal Office for Radiation Protection (BfS) and took place from 2018 to 2020. Participants were requested to measure radon in atmospheres of their own facilities according to their own procedures and requirements for metrological traceability. A measurement device with suitable properties was used to determine the comparison values. The results of the comparison showed that the radon activity concentrations that were determined by European calibration facilities complying with metrological traceability requirements were consistent with each other and had common mean values. The deviations from these values were normally distributed. The range of variation of the common mean value was a measure of the degree of agreement between the participants. For exposures above 1000 Bq/m3, the variation was about 4% for a level of confidence of approximately 95% (k=2). For lower exposure levels, the variation increased to about 6%.

A full-scale experimental study of sub-slab pressure fields induced by underground perforated pipes as a soil depressurisation technique in radon mitigation.

Sub-slab depressurisation systems have proven to effectively mitigate radon entry. A poor understanding of the fluid physics underlying the technique has been shown to lower the success rate substantially. This article describes a study of pressure fields in a sub-slab gravel bed induced by a soil depressurisation system consisting of perforated pipes run under the slab at a depth of 75 cm. The advantage of the approach is that pipes can be laid from outside the building to be protected. The study was conducted on a large-scale experimental facility where the variations in morphology and scope of pressure fields with different pipe combinations could be monitored and characterised. The findings showed that pressure was uniform across the entire area in the gravel bed, whereas the sensors buried in natural soil showed pressure to depend on distance from the source. Pressure transfer to the sub-slab plane was also observed to vary depending on the active pipe. Air-flow resistance studies in the layers of soil lying between the pipes and the gravel delivered different results for each pipe. That finding would appear to be related to the presence of preferential pathways in some parts of the soil. Total pressure when several pipes were activated was observed to be practically the same as the sum of the pressures transferred by each when working separately. The correlation between extraction fan power and pressure generated was also analysed. These and other factors are discussed and analysed from a perspective of the understanding of such highly effective techniques.

Intercomparison of Indoor Radon Measurements Under Field Conditions In the Framework of MetroRADON European Project.

Interlaboratory comparisons are a basic part of the regular quality controls of laboratories to warranty the adequate performance of test and measurements. The exercise presented in this article is the comparison of indoor radon gas measurements under field conditions performed with passive detectors and active monitors carried out in the Laboratory of Natural Radiation (LNR). The aim is to provide a direct comparison between different methodologies and to identify physical reasons for possible inconsistencies, particularly related to sampling and measurement techniques. The variation of radon concentration during the comparison showed a big range of values, with levels from approximately 0.5 to 30 kBq/m3. The reference values for the two exposure periods have been derived from a weighted average of participants' results applying an iterative algorithm. The indexes used to analyze the participants' results were the relative percentage difference D(%), the Zeta score ( ζ ), and the z-score ( z ). Over 80% of the results for radon in air exposure are within the interval defined by the reference value and 20% and 10% for the first and the second exposure, respectively. Most deviations were detected with the overestimating of the exposure using passive detectors due to the related degassing time of detector holder materials.

VARIATION OF INDOOR RADON CONCENTRATION WITHIN A RESIDENTIAL COMPLEX.

A recent challenge in research dedicated to residential exposure to radon comes from the growing number of houses retrofitted to reduce energy consumption. Efficiently insulated buildings and modern architectural solutions can lead to the accumulation of high levels of indoor pollutants. A systematic analysis was conducted in a residential complex (consisting of six houses) in order to assess the annual radon concentration and to evaluate the intensity of the relationships with various factors, such as the indoor-outdoor temperature differences, wind speed and wind direction. Three types of occupational behaviour, influencing the ventilation rate of the dwellings and, implicitly, the indoor radon activity concentration were observed. By calculating the partial correlation coefficient between the radon concentration and the wind direction, with the wind speed as the control variable, for all six houses the correlation coefficient presents negative values.

Radon mitigation by soil depressurisation case study: Radon concentration and pressure field extension monitoring in a pilot house in Spain.

A one-year monitoring study was conducted in a pilot house with extremely high radon levels to investigate the ability and efficiency of radon mitigation by soil depressurisation (SD) both active and passive. The study included monitoring of radon concentration, pressure field extension (PFE) under the slab and some atmospheric parameters for different testing phases. Periods in which the house remained closed to foster radon accumulation were alternated with phases of active and passive soil depressurisation under different conditions. The behaviour of the radon concentration in the pilot house was analysed along with the influence of atmospheric variables, significant correlations were found for the radon concentration with atmospheric pressure, outdoor temperature and wind. From the PFE analysis it was proven that the pressure drop with distance from the suction point of the SD system is proportional to the depressurisation generated. A behaviour law was found for the permeability characterisation of the house based on the active SD performance and also, the relationship between wind velocity and extraction airflow during passive SD operation by means of a rotating cowl was obtained. Radon reductions in excess of 85% were achieved for the different testing phases in all cases. Finally, from the results it was postulated that a fan power of 20 W is sufficient to ensure radon reductions over 85% for dwellings with similar aggregate layer and soil permeability.

Testing and Calibration of CDs as Radon Detectors at Highly Variable Radon Concentrations and Temperatures.

The application of the compact disk (CD) method for radon measurements at mines, caves and other workplaces needs testing under highly variable exposure conditions. We present the results from a blind comparison of CDs exposed in the Laboratory of Natural Radiation (Saelices el Chico, Spain). During the exposure the temperature varied from 6.5 to 24.9 °C (average 12.6 °C) and the 222Rn activity concentrations varied from <10 Bq m-3 to 147 kBq m-3. Good correspondence was observed between the integrated 222Rn activity concentration determined by the reference instruments in the laboratory (122,500 ± 6100 kBq h m-3) and that assessed by analysis of the CDs at a depth 80 µm beneath the front surface (118,000 ± 12,000 kBq h m-3) and at a depth of 120 µm (106,000 ± 12,000 kBq h m-3). The theoretical modeling of the CD response under variable temperature and radon concentration suggested that the small bias is probably due to the time variation of the calibration factor because of the time variations of the temperature.

Continuous monitoring of radon gas as a tool to understand air dynamics in the cave of Altamira (Cantabria, Spain).

The use of radon as an atmospheric tracer in the Altamira Cave over the past 30years has provided relevant information about gaseous exchanges between the Polychromes Room, the adjoining Chambers inside the cave, and the outside atmosphere. The relatively simple physico-chemical behaviour of radon gas provides a marked advantage over other tracer gases that are usually present in high concentrations in hypogeous environments, such as CO2. Two types of continuous radon measurement were undertaken. The first involves active detectors located in the Hall and Polychromes Room, which provide radon concentration values at 1-hour intervals. In addition, nuclear solid track etched detectors (CR-39) are used in every chamber of the cave over 14-day exposure periods, providing average radon concentrations. In this paper we show some of the specific degassing and recharge events identified by anomalous variations in the concentration of radon gas in the Polychromes Room. In addition, we update knowledge regarding the degree of connection between chambers inside the cave and with the outside atmosphere. We verify that the connection between the Polychromes Room and the rest of the cave has been drastically reduced by the installation of the second closure in 2008. Except for point exchanges with the Crossing zone generated by a negative temperature gradient in that direction, the atmosphere of the Polychromes Room remains stable, or else it exchanges matter with the outside atmosphere through the karst interface. The role of radon as a tracer is demonstrated to be valid both to reflect seasonal cycles of degassing and recharge, and to analyse shorter (daily) period fluctuations.

Residential radon and cancer mortality in Galicia, Spain.

Residential radon exposure is a serious public health concern, and as such appears in the recommendations of European Code Against Cancer. The objective of this study was to assess the association between residential radon levels and mortality due to different types of cancer, using misaligned data analysis techniques. Mortality data (observed cases) for each of the 313 Galician municipalities were drawn from the records of the National Statistics Institute for the study period (1999-2008). Expected cases were computed using Galician mortality rates for 14 types of malignant tumors as reference, with a total of 56,385 deaths due to the tumors analyzed. The effect estimates of indoor radon (3371 sampling points) were adjusted for sociodemographic variables, altitude, and arsenic topsoil levels (1069 sampling points), using spatial/geostatistical models fitted with stochastic partial differential equations and integrated nested Laplace approximations. These models are capable of processing misaligned data. The results showed a statistical association between indoor radon and lung, stomach and brain cancer in women in Galicia. Apart from lung cancer (relative risk (RR)=1.09), in which a twofold increase in radon exposure led to a 9% rise in mortality, the association was particularly relevant in stomach (RR=1.17) and brain cancer (RR=1.28). Further analytical epidemiologic studies are needed to confirm these results, and an assessment should be made of the advisability of implementing interventions targeting such exposure in higher-risk areas.

Analysis of the main factors affecting the evaluation of the radon dose in workplaces: the case of tourist caves.

High concentrations of radon exist in several workplaces like tourist caves mainly because of the low ventilation rates existing at these enclosures. In this sense, in its 1990 publication, the ICRP recommended that high exposures of radon in workplaces should be considered as occupational exposure. In developed caves in which guides provide tours for the general public great care is needed for taking remedial actions concerning radon, because in some circumstances forced ventilation may alter the humidity inside the cave affecting some of the formations or paintings that attract tourists. Tourist guides can work about 1900 h per year, so the only option to protect them and other cave workers from radon exposure is to apply an appropriate system of radiation protection mainly based on limitation of exposure by restricting the amount of time spent in the cave. Because of the typical environmental conditions inside the caves, the application of these protecting actions requires to know some indoor air characteristics like particle concentration, as well as radon progeny behaviour in order to get more realistic effective dose values In this work the results of the first two set of radon measurements program carried out in 10 caves located in the region of Cantabria (Spain) are presented.

Low doses of alpha particle irradiation modify the expression of genes regulating apoptosis in human MCF-7 breast cancer cells.

The possibility of modifying apoptosis-related genes in tumor cells is an interesting line of research that calls for multidisciplinary experimentation to describe its characteristics and the conditions required. In vitro low doses of alpha particle irradiation due to radon have an antiproliferative effect on the growth of MCF-7 cells and increase the sensibility of cancer cells to taxol, a chemotherapeutic agent that induces cellular apoptosis. The present study examines the in vitro effects of low doses of alpha particle irradiation from the gas radon on the expression of some bcl-2 family apoptosis-related genes. The analyzed genes were bax, bcl-2 and bcl-x, with known responses to genotoxic stress (bcl-2) or ionising radiation (bax and bcl-x) in MCF-7 human breast cancer cells. The results obtained indicate that the cell line studied expresses the mentioned genes and they demonstrate that irradiation with low radon doses of MCF-7 cells induces underexpression of both bax and bcl-2 genes. Interestingly, the mRNA levels of the full-length bcl-x gene (bcl-xL) were overexpressed after irradiation, and we found significant mRNA levels of an alternative mRNA splicing form of the same gene (bcl-xS), which enhances the apoptotic sensitivity of the cell. The increased sensitivity to apoptosis resulting from bcl-xS overexpression is important because it might improve the efficacy of chemotherapeutic agents used to treat cancers which act through induction of apoptosis. The finding that low radiation doses of alpha particles from the gas radon modulate the expression of apoptosis-related genes suggests a therapeutic utility for this naturally occurring agent.