Metrology aspects (sampling, storage, transportation, and measurement) of radon in water

Background: Radon can enter homes using water during normal household activities, and it contributes to increasing the radon concentration of the adjacent space. Because of its gaseous form, it can easily escape during one of the procedures preceding its measurement (sampling, transport, and storage) and during its measurement resulting in its underestimation, which could lead to an underestimated dose calculation. Objectives: This study focused on quantifying and evaluating radon losses during sampling, transporting, and storing radon in water samples. Also, in terms of measuring radon in water activity concentration, two emanometry methods were compared to the direct method of gamma-ray spectrometry. Design and Methods: In terms of sampling, two methods were examined and compared. Road transport effect on radon losses was studied by measuring the radon in water concentration of radon-rich samples before and after their transportation at different ambient temperatures. Different materials (PET, glass, aluminum) were examined for their radon tightness by repetitive measurements and interpolation of the recorded data. Also, the effect of ambient temperature (1 to 40°C) on radon losses was studied during the storage phase. To compare radon in water measuring methods, water from the original bottle was poured carefully into the different sample containers that each method requires and measured by each method. Results and Conclusions: Sampling is the factor that can cause the most significant radon losses. Radon tightness investigation of different materials showed no significant differences in their ability to preserve radon inside the container, as their fitting curves followed the literature radon decay curve. Ambient temperature (1 to 40 °C) did not appear to affect radon losses during the storage phase. Unlike the storage phase, significant radon losses were observed during road transport at ambient temperatures of 31°C and above. Therefore, measures should be taken to avoid radon losses for ambient temperatures of 31°C and above when road transport is considered (e.g., using thermally insulated boxes and cooling elements). From the comparison of the two emanometry methods with gamma-ray spectrometry, it was found that all methods provide equal results within standard uncertainties

Time variation of radon in tap water in locations of a Greek area with geological background for elevated radon-in-water concentrations and correlation study between radon, gross alpha, uranium, and radium concentrations

Background: Radon (222Rn), a naturally occurring radioactive gas, dissolves in water, and it can be found in elevated concentrations in public water supplies when water originates from ground sources in areas rich in uranium. An area of great interest for measuring radon-in-water is the Migdonia basin in Northern Greece due to its geological background and because all of its villages are supplied with water from boreholes. Objectives: The main aim of this paper was to study the time variation of radon in tap water activity concentration in nine villages of the Migdonia basin supplied with water from boreholes and to determine factors that may affect it. Radon in water correlation between the source (borehole) and the consumption point (tap) was studied for some villages. Also, the correlation among radon, gross alpha, beta, uranium (238U), and radium (226Ra) activity concentration in water was studied. Design and methods: Water samples were collected and measured for their radon activity concentration from 66 villages in the Migdonia basin in order to find places with relatively high radon concentrations. The time variation of radon-in-water was studied for villages that showed relatively high radon concentrations for 3 to 4 years (2018–2022). All samples were measured for their 222Rn activity concentration using gamma-ray spectrometry. Water samples were also analyzed for their gross alpha, beta, and uranium isotopes activity concentration. Results and conclusions: Average radon in tap water activity concentrations measured in the area ranged from background concentrations to 185 Bq L-1. The corresponding annual effective doses from waterborne radon inhalation using both UNSCEAR and ICRP dose conversion factors ranged from 0.01 to 0.466 mSv y-1 and from 0.02 to 0.868 mSv y-1, respectively, while radon ingestion annual effective doses varied from 0.007 to 0.324 mSv y-1. Time variation of radon activity concentration in tap water for villages supplied from one borehole or a constant number of boreholes showed relatively low standard deviations (<24 percent) at a coverage factor of k = 1. Those deviations are probably caused by the time variation of boreholes’ radon concentration and water demand changes. A significant decline in radon concentration from the source (borehole) to the consumption point (tap water) was observed. Therefore, sampling should be performed at the consumption point. However, knowing the supplying borehole concentration is useful as it determines the potential for radon in drinking water. No apparent correlation was found among radon, gross alpha, beta, uranium, and radium concentrations in water. However, in some cases, remedial actions (withdrawal of boreholes) for uranium concentration also decreased radon concentration

Response of radiation detectors to terrestrial and cosmic radiation

This PhD (Doctoral Thesis-DT) objective is to investigate the response of radiation detectors to terrestrial and cosmic radiation. With the help of in situ measurements, that took place at the Telemetric Early Warning System Network of the Greek Atomic Energy Commission, an attempt to optimize the response characteristics of the system was conducted. The Telemetric Network of EEAE consists of a network of 24 Reuter-Stokes high-pressure ionization chambers (HPIC) detectors that measure dose rate and geographically cover the whole territory of Greece. The response of the Reuter-Stokes detectors to terrestrial and cosmic radiation was evaluated in comparison with spectroscopic data from in situ gamma spectrometry measurements performed with portable High purity Germanium detectors (HPGe) and gamma spectrometric laboratory measurements of soil samples taken from eight of the Telemetric Network stations. Furthermore, through the analysis of the timeseries, that was created from data of dose rate measurements by the detectors and expands over two decades, a correlation of those values with atmospheric phenomena and cosmic radiation was investigated. At the same locations, dose measurements were conducted with the use of passive electret ionization chambers and the results of those measurements are evaluated. Last but not least, at the previous mentioned locations the radon exhalation rate from soil was measured and the correlation between those values and the gamma dose rate measured at the same locations was evaluated.Η διδακτορική διατριβή (ΔΔ) έχει ως αντικείμενο τη διερεύνηση της απόκρισης των ανιχνευτών ραδιενέργειας τόσο στη γήινη ακτινοβολία όσο και στη κοσμική. Μέσα από επιτόπιες μετρήσεις στο Τηλεμετρικό Σύστημα Μέτρησης Ραδιενέργειας της Ελληνικής Επιτροπής Ατομικής Ενέργειας επιχειρείται μια βελτιστοποίηση των χαρακτηριστικών απόκρισης του συστήματος. Το δίκτυο τηλεμετρικών συστημάτων έγκαιρης προειδοποίησης της Ελληνικής Επιτροπής Ατομικής Ενέργειας αποτελείται κυρίως από ένα δίκτυο 24 θαλάμων ιοντισμού υψηλής πίεσης Reuter-Stokes (HPIC) για μετρήσεις ρυθμού δόσης και καλύπτει όλη την Ελλάδα. H απόκριση των ανιχνευτών Reuter-Stokes στην γήινη και κοσμική ακτινοβολία αξιολογήθηκε σε σύγκριση με φασματοσκοπικά δεδομένα που ελήφθησαν από μετρήσεις in-situ γάμμα φασματοσκοπίας με φορητούς ανιχνευτές υπερκαθαρού γερμανίου (HPGe) και εργαστηριακές αναλύσεις δειγμάτων εδάφους με την μέθοδο της γ-φασματοσκοπίας, σε 8 σταθμούς του Τηλεμετρικού Δικτύου. Στη συνέχεια μέσα από ανάλυση χρονοσειρών δόσης, σχεδόν δύο δεκαετιών, επιχειρείται μια συσχέτιση αυτών τόσο με μετεωρολογικά φαινόμενα όσο και με την κοσμική ακτινοβολία. Στις ίδιες τοποθεσίες πραγματοποιούνται μετρήσεις δόσεων με παθητικούς ανιχνευτές θαλάμου ιοντισμού electret και αξιολογούνται τα αποτελέσματα. Τέλος πραγματοποιείται διερεύνηση της εκροής του ραδονίου από το έδαφος στις ίδιες τοποθεσίες, ώστε να εκτιμηθεί η συσχέτιση του με τη μετρούμενη γ-ακτινοβολία

Safety Management of Hazardous Materials - Orphan Radioactive Sources: Contribution of STRASS Project

STRASS project is an INTERREG project, collaboration between Greece and North Macedonia that includes the following aims a) Discovery and identification of radioactive materials (especially orphan radioactive sources and materials that are transferred mainly accidentally) during check in cross border area, b) Location of dangerous points of the roadway Thessaloniki-Skopje. c) Investigation of radiological risk after a traffic accident d) Establishment of common emergency response protocols for both countries. The project deals with circular economy and sustainability and its main challenge that is presented here is to minimize any risk of accident (traffic accident during transportation, dispersion, loss etc) and pollution when handling and transferring willfully or accidentally hazardous radioactive materials

In-depth study of radon in water in a Greek village with enhanced radon concentrations

This study focused on the radon transfer from the water to the air and the subsequent impact of waterborne radon indoors, taking advantage of the enhanced and decreasing from year to year radon-in-water concentrations observed in the Arnea village in Northern Greece. Some other essential aspects and observations regarding radon-in-water were also discussed. Concerning radon transfer from water to the air, the transfer efficiencies for showering and the use of the bathroom tap were estimated by measuring the radon-in-water and the waterborne radon-in-air concentrations in sealed bathrooms of two apartments in Arnea. The transfer efficiency for the bathroom tap use ranged from 22 to 28.9% for water flow rates of 2.7–7 L min−1. For showering, the transfer efficiency ranged from 45 to 48.3% for water flow rates of 6 L min−1 and 8 L min−1, respectively. As for the impact of waterborne radon indoors, each year's two-week monitoring of radon-in-water and radon-in-air concentrations in a house in Arnea from 2018 to 2022 revealed rapid and sharp increases in the bathroom air related to waterborne radon. Following the results obtained in the house's bathroom in Arnea, showering is the most significant exposure of humans to waterborne radon due to the person's proximity to waterborne radon, the enclosed space, the high transfer efficiency of showering, and the significant amount of water consumed. Each year's two-week average indoor radon concentrations measured in the examined house in Arnea showed that waterborne radon's contribution is less important than the other parameters affecting indoor radon, such as ventilation rates and radon emanation from the soil beneath the house's structure. Time variation (2018–2022) of radon activity concentration measured in a borehole supplying Arnea with water showed a relatively low standard deviation (10.2%) at a coverage factor of k = 1. A disequilibrium was observed between radon and its progenies immediately after pumping water from a borehole. This disequilibrium was observed for 1.3 years and seems to be continuous. Regarding radon removal from water, the diffused bubble aeration System constructed in Arnea reduces the radon-in-water activity concentration by more than 90% when using an air-to-water ratio of 10:1 and a detention time of 60 min. The System does not affect the adjacent outer space radon-in-air concentrations