Comparison of Radionuclide Impurities Activated during Irradiation of 18O-Enriched Water in Tantalum and Silver Targets during the Production of 18F in a Cyclotron.

During the production of 18F, as a result of the interaction of the beam of protons and secondary neutrons with the structural elements of the target body, many radionuclide impurities are created in the cyclotron. As part of this work, we theoretically predicted which isotopes would be activated in the target tantalum or silver bodies. Subsequently, we used gamma spectrometry analysis to verify these predictions. The results were compared with the work of other authors who studied titanium and niobium as materials for making the target body. Tantalum has been evaluated as the most favorable in terms of generating radionuclide impurities during the production of 18F by irradiation of 18O-enriched water in accelerated proton cyclotrons. Only three radionuclides were identified in the tested samples: 181W, 181Hf, and 182Ta with a half-life of fewer than 120 days. The remaining reactions led to the formation of stable isotopes.

Public Health Decision Making in the Case of the Use of a Nuclear Weapon.

The current geopolitical situation and the war on Ukraine's territory generate questions about the possible use of a nuclear weapon and create the need to refresh emergency protective plans for the population. Ensuring the protection of public health is a national responsibility, but the problem is of international size and global scale. Radiological or nuclear disasters need suitable decision making at the right time, which determine large effective radiation protection activities to ensure public health is protected, reduce fatalities, radiation disease, and other effects. In this study, a simulation of a single nuclear weapon detonation with an explosion yield of 0.3 and 1 Mt was applied for a hypothetical location, to indicate the required decision making and the need to trigger protocols for the protection of the population. The simulated explosion was located in a city center, in a European country, for the estimation of the size of the effects of the explosion and its consequences for public health. Based on the simulation results and knowledge obtained from historical nuclear events, practical suggestions, discussion, a review of the recommendations was conducted, exacerbated by the time constraints of a public health emergency. Making science-based decisions should encompass clear procedures with specific activities triggered immediately based on confirmed information, acquired from active or/and passive warning systems and radiometric specific analysis provided by authorized laboratories. This study has the potential to support the preparedness of decision makers in the event of a disaster or crisis-related emergency for population health management and summarizes the strengths and weaknesses of the current ability to respond.

Radioactive fossils: The uranium anomaly and its paleobiological implications.

In this study, several natural radionuclides (40K, 238U, 235U, 228Ac) and their decay product were investigated in various invertebrate and vertebrate fossils. In the high radioactivity group of fossils, 238U and 235U concentrations increased from 141 to 3621 Bq/kg and from 5.4 to 167 Bq/kg, respectively. In the low radioactivity group of fossils, concentrations of both U isotopes increased from 4.6 to 51 Bq/kg and from 0.18 to 2.3 Bq/kg, respectively. High radioactivity has been linked to the phosphatization process that affected the uranium sorption. Scanning of electron microscope images and X-ray fluorescence analysis were used to confirm the mode of preservation of studied fossils and the presence of a correlation between the phosphorus content and uranium elements in fossil specimens.

Occurrence of 222Rn and 226,228Ra in underground water and 222Rn in soil and their mutual correlations for underground water supplies in southern Greater Poland.

European Union Council Directive 2013/51/EURATOM recently sets out so-called indicator parameters for: radon, tritium and indicative dose of water intended for human consumption. The aim of this research was to elaborate an effective procedure for determination of radon and radium 226,228Ra isotopes (which are potentially the main contributors to the internal dose from drinking and cooking water) and to find the possible relationships between these radionuclides in underground water reservoirs and 222Rn concentration in the soil gas in their vicinity. The research was performed by applying a non-volatile and water-immiscible scintillation cocktail based on a pure diisopropylnaphthalene (Ultima Gold F: UGF), which allow for efficient radon extraction from 0.5 dm3 of water samples to 20 cm3 of scintillation phase and its direct determination with a detection limit of 5 × 10-3 Bq dm-3. The further preliminary concentration of 3 dm3 of crude water samples by evaporation to 0.5 dm3 samples led to the removal of all unsupported 222Rn activity and allowed the 226Ra determination via equivalent 222Rn detection after one-month samples storage using a low-background Triathler liquid scintillation counter in the α/ß separation counting mode. Together with determination of 226Ra isotope in water samples, the simultaneous measurements of 228Ra and 222Rn radionuclides concentrations in water as well as 222Rn activity in the soil gas around the water supply sites were performed. The achieved limit of 226Ra detection was at a very low level of 10-3 Bq dm-3. The measured values of 226Ra concentration in 50 public underground water supply units for the Kalisz district of Poland were relatively low and ranged from below detection limit to 28.5 × 10-3 Bq dm-3 with arithmetic mean and median values of 12.9 and 12.2 × 10-3 Bq dm-3, respectively. Weak correlations were observed between activity concentrations of 226Ra and 222Rn in the crude water samples (R2 = 0.31) and 222Rn in water and its concentration in the nearby soil gas (R2 = 0.48).

Modeling of 210Pb and 210Po radionuclide emissions from local power plants in central Poland.

Due to the more volatile nature of 210Po in relation to 210Pb, an imbalance of activity concentrations in high temperature combustion processes can be observed, especially in fine particulates (diameter < 0.1, 0.2 and 0.5 µm). In the atmosphere and in the soil around coal-fired power plants, 210Pb and 210Po concentrations are a combination of activities from natural and anthropogenic sources. In this study only portions of 210Po and 210Pb radionuclides resulting from energy production activities were analyzed. Due to the high mobility of fine particles, a surface area of 172 km × 140 km in central Poland was chosen for simulation. For validation of the modeling approach, three grid versions were applied: 1 km, 2 km and 4 km. Simulated results confirmed experimental-computational values of an excess of both radionuclides in the atmosphere in 2017 in the city of Lodz. Different aerosol fractions, seasons and various grids in the selected area were subjected to 36 individual simulations. The 210Po activity concentrations measured in winter and summer 2017 were 42.5 and 8.99 µBq m-3, respectively. Simulated and measured values of artificial 210Po and 210Pb activities are well correlated.

Formation of 107Cd radionuclide impurities during 18F production.

Cd isotopes (107Cd and 109Cd) are generated from the silver target body during the bombardment of [18O]water in the routine production of 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG) for PET (Positron Emission Tomography) diagnosis. Cadmium isotopes contribute significantly to the total activity of generated impurities and, due to being potentially radiotoxic to living organisms, they should be effectively reduced from FDG to prevent accidental injection of even small concentrations into patients. Purification of the final [18F]FDG can be based on a set of columns, fulfilling various functions in the cleaning process. To assess cadmium impurities and the efficiency of the purification process, a low background gamma spectrometry system with high resolution has been applied. Even activity of 3.5 kBq and 290 kBq has been measured on QMA (Sep-Pak Light Accell Plus QMA) columns for 109Cd and 107Cd isotopes, respectively. 107Cd activity in the five column set was higher than that of 109Cd. The rate of 18F production process was about 1 GBq/min, while that of 107Cd and 109Cd radionuclides was about 4.2 kBq/min and 50 Bq/min respectively. The same purification efficiency of both isotopes has been obtained at each step of the process. The production rate of 107Cd and 109Cd radionuclides was insignificant compared to the 18F production rate. Therefore [18F]FDG final product for use in injections before PET diagnostics was efficiently purified from cadmium radionuclide impurities.

Chemometric methods for source apportionment of 210Pb, 210Bi and 210Po for 10 years of urban air radioactivity monitoring in Lodz city, Poland.

The radionuclide activity concentrations of 210Pb and its decay products 210Bi and 210Po were measured in 271 total suspended particulate samples collected from 2008 to 2017 in the center of Lodz city, Poland. Natural and anthropogenic contributions to the observed activities of 210Pb, 210Bi and 210Po radionuclides were estimated. Corrected aerosol residence times were determined for this purpose. After the closure of one of the coal-fired power plants located in the center of the city, a substantial reduction in emission of these radionuclides was observed. For proper identification of the origins of these radionuclides, the concentrations of 4 K and 7Be as well as sulfur dioxide (SO2), and total air particulate matter were measured. Principal component analysis and cluster analysis were conducted for source apportionment of 210Pb, 210Bi and 210Po in urban air.

Kinetics of 210Po accumulation in moss body profiles.

Radionuclide concentration analysis of total moss bodies often gave relatively different results than a separate analysis of each different morphological part of the same sample. The dynamics of the transfer of metals by dust uplifted from the soil and another approach, based on the diffusion of the two radionuclides to the moss, have been analyzed. In the proposed model, short- and long-term approaches have been applied. Each part of a moss's profile can show different radionuclides accumulation ability, including both 210Pb and 210Po isotopes. A first-order kinetic model has been used for 210Po and 210Pb transport between three body components of mosses. This mathematical approach has been applied for 210Po activity concentration in the air estimation. For relatively clean deep forest region, calculated concentrations were from 17.2 to 43.8 µBqm-3, while for urban air concentrations were higher from 49.1 to 104.9 µBqm-3.

Application of modern anticoincidence (AC) system in HPGe γ-spectrometry for the detection limit lowering of the radionuclides in air filters.

The use of active and passive shields can substantially reduce the Minimum Detectable Activity (MDA) of the γ-ray counting systems, rejecting events induced by cosmic-rays or by environmental radioactivity. However, the size and geometry of the samples lead to limitations in the background reduction in routine measurements. The Minimum Detectable Activity (MDA) values for low energy of γ-ray emitting radionuclides (<200 keV) deposited in three typical air filter geometries have been compared for anticoincidence and single HPGe detector mode of γ-spectrometry systems. The relative increase in the Figure Of Merit (FOM) values from to 10-37% has been achieved for AC counting mode for radionuclides of 210Pb, 234Th, 235U and 226Ra deposited on the three kinds of air filters.

Indoor 222Rn concentration in the exhibition and storage rooms of Polish geological museums.

The radon exhaled from radioactive mineral collections exhibited in five Polish geological museums may influence its total indoor concentration. Radon concentrations measured in the exhibition halls do not pose a risk for visitors or museum staff. However, air exceeding the ICRP (2007) action limit for workers (equal to 300Bq/m3) was noted in the storage rooms of two museums. Significant222Rn activity concentrations equal to more than ~300kBq/m3were measured inside lead containers where radioactive minerals were stored.

Comparison of two spectrometric counting modes for fast analysis of selected radionuclides activity.

The two counting modes: a normal with a single HPGE detector and second with the additional anti-Compton shield of the annular NaI(Tl) detector have been compared for fast determination of the activity concentration of thorium 232Th in the building materials. The 232Th activity concentration was calculated by measurement of its decay products: 212Pb, 212Bi and 208Tl as well 228Ac content. Although the Compton suppression mode applied in gamma spectrometry systems in general increase sensitivity of the analysis, but in case of 583 keV the most abundant 208Tl γ-line, the significant reduction of photon counting rate was observed.

The sources and fate of (210)Po in the urban air: A review.

The origin of (210)Po activity and its fluctuations in the air are discussed in this paper. In the case of atmospheric aerosol samples, a comparison of the (210)Po/(210)Pb and (210)Bi/(210)Pb activity ratios makes it possible not only to determine aerosol residence times but also to appraise the contribution of the unsupported (210)Po coming from other sources than (222)Rn decay, such as human industrial activities, especially coal combustion. A simple mathematical method makes it possible to observe the seasonal fluctuations of the anthropogenic excess of (210)Po in the urban air. The average doses of (210)Po intake with food (including drinking water) and inhalation of urban aerosols are usually lower than those from (210)Po intake by cigarette smokers and negligible in comparison to total natural radiation exposure.

Direct determination of radionuclides in building materials with self-absorption correction for the 63 and 186 keV γ-energy lines.

The use of 911 keV and 129 keV γ-line intensity ratio has been applied for self-absorption correction of the 63 keV (234)Th ((238)U) and 186 keV((226)Ra and (235)U) lines in typical building materials and soil samples. Proposed procedure allows to determine (238)U from the (234)Th line (63 keV) and (226)Ra after subtraction of (235)U interference in the 186 keV. It is important in the case of low uranium concentration and weak intensity of (235)U 143 keV γ energy line, when activity of this radionuclide can be apprised on the natural constant (238)U/(235)U ratio, only (excluding accidental anthropogenic depleted uranium deposition in the soil samples). Therefore, by this method a direct and fast determination of the (226)Ra and other important radionuclides, without one month waiting period for (226)Ra-(222)Rn daughter equilibrium, is possible. The accuracy of the method has been confirmed (relative relation deviation <10%) for typical buildings materials such as: tales, bricks, concrete blocks and various type of ceramic materials.

Excess of ²¹°polonium activity in the surface urban atmosphere. Part (1) fluctuation of the ²¹°Po excess in the air.

The concentrations of (210)Pb, (210)Bi, and (210)Po in the urban atmosphere of Lodz city were measured from February 2010 to May 2010 and from May 2011 to April 2012. The seasonal changes in the activity ratios for (210)Po/(210)Pb and (210)Bi/(210)Pb indicated that the observed fluctuations were independent of the concentration of tropospheric (210)Pb and its decay products, particularly (210)Po. A simple calculation method was proposed for the estimation of the excess of (210)Po in urban aerosols in relation to the fraction of its activity formed from (210)Pb. On the basis of the results obtained, it was concluded that a substantial part of the (210)Po in urban air did not come from the decay of atmospheric (222)Rn, but rather it was from artificial sources. The highest levels of measured total (210)Po activity were observed during the winter period. This observation suggests that the main source of (210)Po in the investigated region could be related to anthropogenic emissions from domestic heating systems and local coal power plants, rather than from other sources, such as soil resuspension or stratospheric air intrusion as usually suggested in the literature.

Excess of polonium-210 activity in the surface urban atmosphere. Part 2: origin of ²¹°Po excess.

The presence of significant (210)Po activity, unsupported by its grandparent radionuclide (210)Pb, in the surface atmosphere of industrialized regions can originate from human technical activities. In urban air, the activity ratio of (210)Po to (210)Pb might increase as a result of natural condensation and coagulation processes of relatively volatile (210)Po-containing species emitted during coal combustion processes. The presence of excess of (210)Po cannot be explained by its in-growth from radioactive decay of (210)Bi. About 50% of (210)Po radionuclide released during coal combustion processes can be emitted into air as gaseous or ultrafine products. Subsequently, these products are quickly attached to the surface of fine particles suspended in the air. As a result, an excess of (210)Po activity in aerosols has been reported. However, in this manner, As much as 11 GBq of (210)Po per year can enter the urban air from the local coal power plants in Lodz city, Poland.

Use of moss and lichen species to identify (210)Po-contaminated regions.

(210)Po concentration in urban air fluctuates as a result of natural (222)Rn radionuclide exhalation and technical activity that is especially linked with high-temperature processes. Each year, an average 11 GBq of (210)Po is released from local power plants into urban air. Over two months, about 180 samples in central Poland were collected. To detect the concentration of (210)Po activity, two common species of biomonitors were chosen: the moss Pleurozium schreberi and the lichen Hypogymnia physodes. For the same locale, (210)Po in lichen shows an average of twice the amount of activity concentration than the moss. In moss, (210)Po concentrations in Lodz ranged from 41.5 Bq kg(-1) to 258.0 Bq kg(-1), while in lichen it ranges from 74.2 Bq kg(-1) to 670.9 Bq kg(-1). On the basis of the measured activity of (210)Po maps, radionuclide distribution has been prepared. For areas identified with higher concentrations of (210)Po, Quantum Gis has been applied.

Size distributions of airborne radionuclides from the fukushima nuclear accident at several places in europe.

Segregation and radioactive analysis of aerosols according to their aerodynamic size were performed in France, Austria, the Czech Republic, Poland, Germany, and Greece after the arrival of contaminated air masses following the nuclear accident at the Fukushima Dai-ichi nuclear power plant in March 2011. On the whole and regardless of the location, the highest activity levels correspond either to the finest particle fraction or to the upper size class. Regarding anthropogenic radionuclides, the activity median aerodynamic diameter (AMAD) ranged between 0.25 and 0.71 µm for (137)Cs, from 0.17 to 0.69 µm for (134)Cs, and from 0.30 to 0.53 µm for (131)I, thus in the "accumulation mode" of the ambient aerosol (0.1-1 µm). AMAD obtained for the naturally occurring radionuclides (7)Be and (210)Pb ranged from 0.20 to 0.53 µm and 0.29 to 0.52 µm, respectively. Regarding spatial variations, AMADs did not show large differences from place to place compared with what was observed concerning bulk airborne levels registered on the European scale. When air masses arrived in Europe, AMADs for (131)I were about half those for cesium isotopes. Higher AMAD for cesium probably results from higher AMAD observed at the early stage of the accident in Japan. Lower AMAD for (131)I can be explained by the adsorption of gaseous iodine on particles of all sizes met during transport, especially for small particles. Additionally, weathering conditions (rain) encountered during transport and in Europe in March and April contributed to the equilibrium of the gaseous to total (131)I ratio. AMAD slightly increased with time for (131)I whereas a clear decreasing trend was observed with the AMADs for (137)Cs and (134)Cs. On average, the associated geometric standard deviation (GSD) appeared to be higher for iodine than for cesium isotopes. These statements also bear out a gaseous (131)I transfer on ambient particles of a broad size range during transport. Highest weighted activity levels were found on the 0.49-0.95 µm and on the 0.18-0.36 µm size ranges in France and in Poland, respectively. The contribution from resuspension of old deposited (137)Cs was assessed for the coarse particle fractions only for the first sampling week.

Fast procedure for self-absorption correction for low γ energy radionuclide 210Pb determination in solid environmental samples.

Low-energy X and γ radiations (for example of 210Pb: Eγ = 46.5 keV) are effectively self-absorbed even in thin environmental samples, including air filters with captured dust or contaminated soil, as well as in bottom sediment matrixes with limited quantities of the samples. In this paper, a simple method for the direct analysis of 210Pb (T1/2 = 22.3 years) by gamma-ray spectrometry in environmental samples with self-absorption correction is described. The method is based on the comparison of two γ peak activities coming from other natural radionuclides, usually present in environmental samples. We have analyzed the dependence of the self-absorption correction factor for the 210Pb activity on the activity ratios of 911 and 209 keV peaks and 609 and 295 keV peaks coming from nuclides of 238U or 232Th rows, present in typical environmental samples.

Aerosol residence times and changes in radioiodine-131I and radiocaesium-137 Cs activity over Central Poland after the Fukushima-Daiichi Nuclear reactor accident.

The first detectable activities of radioiodine (131)I, and radiocaesium (134)Cs and (137)Cs in the air over Central Poland were measured in dust samples collected by the ASS-500 station in the period of 21(st) to 24(th) of March, 2011. However, the highest activity of both fission products, (131)I and (137)Cs: 8.3 mBq m(-3) and 0.75 mBq m(-3), respectively, were obtained in the samples collected on 30(th) March, i.e.∼18 days after the beginning of the fission products' discharge from the damaged units of the Fukushima Daiichi Nuclear Power Plant. The simultaneously determined corrected aerosol residence time for the same samples by (210)Pb/(210)Bi and (210)Pb/(210)Po methods was equal to 10 days. Additionally, on the basis of the activity ratio of two other natural cosmogenic radionuclides, (7)Be and (22)Na in these aerosol samples, it was possible to estimate the aerosol residence time at ∼150 days for the solid particles coming from the stratospheric fallout. These data, as well as the differences in the activity size distribution of (7)Be and (131)I in the air particulate matter, show, in contrast to the Chernobyl discharge, a negligible input of stratospheric transport of Fukushima-released fission products.

Determination of the mean aerosol residence times in the atmosphere and additional 210Po input on the base of simultaneous determination of 7Be, 22Na, 210Pb, 210Bi and 210Po in urban air.

The significant differences in the activities of 210Pb, 210Bi, 210Po and cosmogenic 7Be and 22Na radionuclides in the urban aerosol samples collected in the summers 2010 and 2011 in the Lodz city of Poland were observed. Simultaneous measurement of these radionuclides, after a simple modification of the one compartment model, allows us to calculate both: the corrected aerosol residence times in the troposphere (1 ÷ 25 days) and in the lower stratosphere (103 ÷ 205 days). The relative input of the additional sources (beside of the 222Rn decay in the air) to the total activity concentrations of 210Pb, 210Bi and 210Po radionuclides in the urban air, plays a substantial role (up to 97% of the total activity) only in the case of 210Po.