In this study, the possibility of 222Rn removal through the deferrization/demanganization applied for water treatment was considered, assuming a sorption process. This study demonstrates the possible removal of dissolved radon from groundwater using manganese oxide sand (MnO2) employed in conventional water treatment systems. Four groundwater samples with varying chemical compositions were treated, and the simultaneous removal of 222Rn, Mn2+, Fe2+, NH4+, and NO3- was evaluated. Radon activity was quantified using a Lucas scintillation cell coupled with a Pylon AB-5 system, while inorganic ions were analyzed by ion chromatography. Structural characterization of MnO2 sand by XRD, SEM-EDS, and FTIR confirmed a heterogeneous oxide surface favorable for adsorption. The treatment achieved average removal efficiencies of 95% for 222Rn, 79% for Mn2+, 87% for Fe2+, 85% for NH4+, and 73% for NO3-. Equilibrium adsorption capacities increased with initial contaminant concentrations, indicating a multi-species uptake. Importantly, radon removal was largely independent of coexisting ions. These results reveal the benefit of MnO2-based water treatment, offering an effective solution for simultaneous radon and inorganic contaminant mitigation.

Radon gas is the largest source of public exposure to naturally occurring radioactivity.Radon activity concentration maps, based on atmospheric measurements, as well as radon flux maps can help Member States to comply with the EU Council Directive 2013/59/Euratom and, particularly, with the identification of Radon Priority Areas.Radon can also be used, as a tracer, to improve Atmospheric Transport Models and to indirectly estimate greenhouse gas (GHG) fluxes.This is important for supporting successful GHG mitigation strategies.One approach to estimate GHG fluxes on local to regional scale is the socalled Radon Tracer Method (RTM), which is based on the night-time correlation between atmospheric concentrations of radon and GHG measured at a given station together with information on the radon flux data within the station footprint.Thus, atmospheric monitoring networks are interested or are already measuring atmospheric radon activity concentrations using different techniques but a metrological chain to ensure the traceability of all these measurements was missing.Since 2020 a large consortium engaged in the project traceRadon [1] to develop the missing traceability chains to improve the respective sensor networks http://traceradon-empir.eu/ .This paper presents results in the areas: Novel 226 Ra standard sources with continuous controlled 222 Rn emanation rate, radon chambers aimed to create a reference radon atmosphere and a reference field for radon flux monitoring.The achieved results are making new calibration services far beyond the state of art possible.

Since 2020 a large consortium has been engaged in the project EMPIR 19ENV01 traceRadon to develop the missing traceability chains to improve the sensor networks in climate observation and radiation protection. This paper presents results in the areas of: Novel 226Ra standard sources with continuous controlled 222Rn emanation rate, radon chambers aimed to create a reference radon atmosphere and a reference field for radon flux monitoring. The major challenge lies in the low activity concentrations of radon in outdoor air from 1 Bq∙m-3 to 100 Bq∙m-3, where below 100 Bq∙m-3 there is currently no metrological traceability at all. Thus, measured values of different instruments operated at different locations cannot be compared with respect to their results. Whin this paper, new infrastructure is presented, capable of filling this gap in traceability. The achieved results make new calibration services, far beyond the state of art, possible.

The practical implementation of the European Council Directive no. 2013/59/EURATOM in Romania requires reliable indoor measurements of the radon (222Rn) activity concentration in air. In Romania, several Testing Laboratories were designated for radon activity and/or radon activity concentration in air measurements by the Romanian National Commission for Nuclear Activities Control (CNCAN). The calibration of the instruments used for indoor radon activity concentration measurements is very important. IFIN-HH, through its Ionizing Radiation Metrology Laboratory (LMRI), performed advanced research in the field of radon metrology, using radon standard sources prepared by LMRI, its radon chamber facility and a new reference radon monitor. The most recent results are described in this article. The radon chamber facility from IFIN-HH was technically improved, and new equipment and methods were set up and tested in order to provide new calibration services for customers. Additionally, calibration of the radon monitors was performed, as well as of the systems with solid-state nuclear track detectors, used for radon in air activity concentration measurements. IFIN-HH/LMRI obtained the CNCAN designation as Calibration Laboratory for installations measuring the radon activity concentration in air.

The aims of this study were to determine the radon concentration in natural mineral and tap water and to estimate the resulting ingestion doses received by adults. Physical-chemical characteristics of water samples have also been investigated. In the last years have been an increase of water consumption of both, natural mineral and tap, many sources and producers being available on the market. Thus, the physical-chemical and radiologic parameters of water must be in compliance with the Drinking Water Directive (DWD). Thus, the study presents an assessment of the radioactivity due to 222Rn and 3H in several mineral natural water samples from the north region of Romania, but also in several tap water samples. The methods used were based on gamma spectrometry, gross alpha-beta measurements and beta spectroscopy, but also ICP-MS for chemical parameters. The results of this work showed that the geology and rock types clearly influence the water radon concentration. The radon concentration is lower in the water that passes through sedimentary rocks than that passing through granitic rocks. An important aspect of this work is to provide reliable information regarding radon and tritium concentrations. Radon concentration varied between 0.15±0.05 Bq/L and 11.35±2.97 Bq/L in the natural mineral water samples and between 0.17±0.05 Bq/L and 8.51±2.34 Bq/L in the tap water samples. An estimation of annual effective radiation dose based on the sample results was also made. Calculated values for ingestion dose due to regular consumption of water does not induce a health risk because of the intake of various radionuclides contained in the water. The maximum values being of 47.38 µSv/y. The determined values for the collected samples are below recommended reference levels, but more important aspect is that this study emphasise environmental sustainability in the investigated area.

Indoor and outdoor (atmospheric) radon activity concentrations need to be measured as accurate as possible for radiation protection and for climate applications. Particularly radon concentrations below 100 Bq m −3, useful for the retrieval of radon prone areas and for atmospheric studies, still need a robust metrological chain to ensure their quality. Ones of the most common used commercial continuous radon monitors were compared here under slightly different environmental conditions. The measured data set were divided into two groups (< 100 Bq m −3 and ≥ 100 Bq m −3) to assess the monitors responses and their associated uncertainties. Nevertheless, these results should also to point out if commercial monitors are suitable for monitoring low atmospheric radon concentrations with an associated uncertainty of 10% (k=1). This work, carried out within the EMPIR 19ENV01 traceRadon project, aims to offer a starting point for the development of a future radon monitor as transfer standard to increase the metrological capabilities of atmospheric radon monitoring.

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.

Radon (222Rn) gas is the largest source of public exposure to naturally occurring radioactivity and the identification of radon priority areas is required by the Council Directive 2013/59/Euratom. Radon is also used as a tracer to improve atmospheric transport models and to indirectly estimate greenhouse gas (GHG) fluxes using the Radon Tracer Method (RTM). This method is based on the correlation between atmospheric concentrations of radon and GHG, together with information on the radon flux data. For radiological data, all European countries have installed networks of automatic gamma dose rate monitoring stations and report the real-time information gathered to the European Radiological Data Exchange Platform (EURDEP). So far, atmospheric radon activity concentrations and radon fluxes are not yet reported in EURDEP, nor routinely measured within the European radiological networks although these observations could help to avoid false positives results. Due to above applications, there is a need of building a metrological chain to ensure high quality radon activity concentrations and radon flux measurements. Both climate and radiation protection research communities underline the need for improved traceability in low-level atmospheric radon measurements (Khanbabaee et al., 2021). The EMPIR project 19ENV01 traceRadon1 is aimed towards providing the necessary measurement infrastructure and transfer standards to fulfil this need. Results of this project are particularly important for improving independent GHG emission estimates that support national reporting under the Paris Agreement on climate change and for the Council Directive 2013/59/Euratom, thus benefitting two large scientific communities. In this paper, early results, such as new activity standard developments and an overview of commercial and research radon monitors are presented and discussed. These results will feed into the traceRadon project with respect to radionuclide metrology in air and its potential for the improvement of the RTM.

Through time, both natural and cultural heritage have unfortunately been under threat due to multiple environmental and human-induced factors, which are likely to trigger various hazards such as soil erosion, landslides, or land collapse. The analysis of old cartographic material, aerial imagery, and satellite imagery has been used in multiple studies to observe and understand the changes that archaeological sites have undergone over the last centuries. These efforts are intended, among other things, to raise awareness of the threats affecting cultural heritage and prevent damages and preserve tangible evidence of the distant past. In this study, historical maps and satellite imagery were analyzed to observe how the landscape in the Mostiștea Valley (Romania) has been used over the last 230 years and how the land use has affected the cultural heritage. Land cover and land use (LCLU) changes in the Mostiștea Valley have occurred due to numerous natural and anthropic forces. These changes have resulted in the damage of tangible heritage in the area with varying degrees of intensity. The results of this study allow the quantification of the magnitude of these changes and their impact on different sites in the region.

In the present study, equilibrium parameters of adsorption of bisphenol A (BPA) on multi-walled carbon nanotubes were determined using non-linear Langmuir and Freundlich sorption models and regression methods were applied. In the calculations, some error functions were applied in the non-linear regression analysis, the best fit between the data being obtained, for a minimum error distribution. Non-linear regression analysis and the error distribution suggested Langmuir isotherm model the best one for estimation of equilibrium parameters. The results will be further used in environmental applications for BPA removal from natural waters, taking into account the spontaneous character of the adsorption process, the endocrine disrupting effect of BPA and the reduced toxicological effects of the impregnated sorbents.

Summary The aim of the present study is to highlight the anomalous values of the natural radioactivity of the Menilites formation, Eastern Carpathians (Romania), Tarcău Nappe. In this area are known several landslide-prone areas, as well as methane gas seepages. Their presence and activity are a result of the past tectonic activity in the region, as well as the present-day seismic activity. The measurements included the determination of 40K, 238U, 232Th concentrations and of natural gamma dose rate been performed in situ, in optimum conditions, as well high-resolution measurements of gamma spectrometry measurements in the laboratory.

Radon gas is the largest source of public exposure to naturally occurring radioactivity. However, radon is also a useful tracer for understanding atmospheric processes, assessing the accuracy of chemical transport models, and enabling integrated emissions estimates of greenhouse gases. A sound metrological system for low level atmospheric radon observations is therefore needed for the benefit of the atmospheric, climate and radiation protection research communities. To this end, here we present a new calibration method for activity concentrations below 20 Bq m−3 and a prototype of the first portable radon monitor capable of achieving uncertainties of 5% (at k = 2) at these concentrations. Compliance checking of policy-driven regulations regarding greenhouse gas (GHG) emissions is an essential component of climate change mitigation efforts. Independent, reliable 'top down' methods that can be applied consistently for estimating local- to regional-scale GHG emissions (such as the radon tracer method (RTM)) are an essential part of this process. The RTM relies upon observed radon and GHG concentrations and measured or modeled radon fluxes. Reliable radon flux maps could also significantly aid EU member states comply with European COUNCIL DIRECTIVE 2013/59/EURATOM. This article also introduces the traceRadon project, key aims of which include outlining a standardized approach for application of the RTM, creating infrastructure with a traceability chain for radon concentration and radon flux measurements, and developing tools for the validation of radon flux models. Since radon progeny dominate the terrestrial gamma dose rate, the planned traceRadon activities are also expected to improve the sensitivity of radiation protection early warning networks because of the correlation known to exist between radon flux and ambient equivalent dose rates.

Gross alpha-beta measurement is a worldwide applied technique to determine activity concentration in drinking water. Laboratories have implemented standard methods where standard sources measurements and routine methods are applied to achieve good analytical results. Proficiency testing is among the most used methods to assess the accuracy of the analytical data produced by laboratories, as this also represents a requirement for laboratories which have ISO 17025 and a quality assurance system implemented. The results presented in this paper show the performance of two laboratories for proficiency tests organized by IAEA, to which SALMROM laboratory and Personal Dosimetry Monitoring Laboratory (LDPM) have participated in 3 years. The feedback from the final reports from IAEA reports demonstrates the performance of the laboratories where 17 out of 18 results pass the acceptance criteria. Only one reported result has a warning which means that it did not pass all acceptance criteria. The results served as a basis to improve the laboratory analysis and to optimize accuracy measurements. The overall results of the PTs point out the reliability and traceability of the systems used for drinking water measurements.

Salt mine galleries possess different therapeutic factors that can be used in the treatment of patients with multiple disorders and balneo-climatic underground tourism purposes. The paper presents the characterization from the point of view of radioactivity, the atmospheric radon and gamma radiations dose, and the results of microclimatic investigations the salt mine aerosols, microorganisms and gases concentrations - speleo-therapeutic factors, usable for medical and balneo-climatic tourism purposes in the galleries of Cacica salt mine, Suceava County, Romania. The mean radon concentration at six different locations within the salt mine varied between 20.5 and 96.5 Bq/m(3). A seasonal variation was observed, with higher radon levels during summer and lower values during the winter season. The concentration of the aero-ions, the aerosol dispersion, the concentration of microorganisms, concentration of different gases in the underground, in galleries from Cacica salt mine are also presented.

The selection of an appropriate detector for field measurements, in case of natural radioactivity, is an important task taking into account constraints given by data reliability, time and cost effectiveness. This paper provides the necessary data when choosing a portable spectrometer Gamma Surveyor based on BGO crystal (6.3 in(3)). The proven efficiency of the crystal, the weaker energy resolution but still good comparable results with HPGe results, obtained for U-238, Th-232, K-40 often makes it a good choice. Thus, in this paper some functional parameters, as energy calibration, energy resolution and background of the system are analyzed. In addition, field data, concentrations of radionuclides U-238, Th-232, K-40 (ppm) in surface soil on the Bucharest area are compared with laboratory measurements using HPGe detector. The obtained data, for all three radionuclides, are well correlated.

The work presents the historical evolution, objectives, goals, concepts, chemical and radiometric methods, results and conclusions for salt waters and natural peloids used in pelotherapy. This study assesses chemical composition, natural radioactivity concentrations and the radiological hazard in peloid and salt water samples, from ten places in the Techirghiol Lake from Romania. Pelotherapy is a very important procedure, and thus, the materials used for this purpose must be well characterized to guaranty safety use. Concentrations of elements such as Sr, Ba, Mn, Fe, Sb, Zn, Cu, Pb, Ti, Ni, Cr, As have been measured using ICP-OES analytical technique. The natural radionuclides such as 238U, 226Ra, 232Th and 40K have been determined by gamma-ray spectrometry. The average activity concentrations were of 0.48 ± 0.10 Bq/kg for 238U, 0.60 ± 0.10 Bq/kg for 226Ra, 0.30 ± 0.08 Bq/kg for 232Th and 17.5 ± 1.3 Bq/kg for 40K for salt water samples. Also, the mean activity concentrations for peloids were: 5.70 ± 1.00 Bq/kg for 238U, 6.85 ± 1.60 Bq/kg for 232Th, 15.3 ± 3.7 Bq/kg for 226Ra and 95.8 ± 5.5 Bq/kg for 40K. The results from this study contribute to the identification of possible contaminants in the salt water and peloid, and their association with the potential ecological and human health risk. In this context, of using salt water and peloid in a relatively long treatment period, several radiological indices have been calculated, to determine if the radionuclide's content can be also harmful to human health. The assessment indicates that humans are not exposed to concentrations of metal contaminants higher than the international recommended values.

The study shows the methodology for measuring and assessing the radon concentration in indoor and outdoor environments. The results analyzed in the paper show the radioactive measurements of the natural radiation background from the IFIN-HH and ELI-NP, Romania, for radiometrical purposes, for public health and radiological security. The indoor radon concentration varies from 42 to 154 Bq/m(3) with an average value of 109.4 Bq/m(3), and the outdoor concentration varies from 15 to 28 Bq/m(3) with the average value of 23.1 Bq/m(3). Also, we developed a research study in order to investigate the long-term behavior of the diurnal and seasonal fluctuations of radon Rn-222 and the influence of environmental conditions and other climatic factors. In correlation with the radon concentration measured, the effective dose was also calculated.

This paper presents the work carried out in Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH) for the measurement of indoor and outdoor Rn-222 concentration as a historical development and as present situation, focused on the assurance of its metrological chain, from primary standardization, up to in field measurement. These activities are in tight connection with the activity of education and training for staff involved in exposure to naturally occurring radioactive materials (NORMs), especially radon, and for those involved in the measurement of radon concentrations in field. Two types of training actions will be presented: the courses organized for people working in uranium industry and public health and the course prepared and presented within the ANNETTE EU Project, Horizon 2020 Research and Innovation Programme.