Search Results (13)

Due to the consequences of nuclear and/or radiological accidents in the past (Chernobyl, Fukushima, etc.), and potential future events of that kind, the constant monitoring of environmental radioactivity is important. There are different pathways of the transfer of radionuclides from environment to humans (ingestion, inhalation and external). Food ingestion greatly contributes to the total effective dose; hence, it is of great importance to investigate exposure to radionuclides through food. This paper presents the results of a long-term investigation of ¹³⁷Cs activity concentration in apples in northwestern Croatia for the period 1968–2023. The highest ¹³⁷Cs activity concentration in apples was measured in 1986, decreasing exponentially ever since. The Fukushima-Daiichi accident in 2011 did not cause a significant increase in ¹³⁷Cs activity concentration, although the presence of the consequent fallout was detected via the appearance of ¹³⁴Cs in some parts of the environment. The observed residence time for ¹³⁷Cs in apples was estimated to be 4.5 and 3.9 years for the pre-Chernobyl and post-Chernobyl periods, respectively. The correlation between ¹³⁷Cs in fallout and apples is very good, the correlation coefficients being 0.99, which indicates that fallout is the main source of contamination. The estimated effective dose received by adult members of the Croatian public due to intake of radiocaesium from apples over the overall observed period is 6.4 µSv. Therefore, the consumption of apples was not a critical pathway for the transfer of radiocaesium to humans. Full article

In this paper, the evaluation of the Rn-222 radioactivity content in drinking water samples from the Calabria region, southern Italy, is reported as a case study. The Rn-222-specific activity in the analyzed groundwater samples for human use was evaluated by using the PerkinElmer Tricarb 4910 TR setup and compared with the parameter value (100 Bq L⁻¹) reported in the reference Italian legislation, i.e., D.Lgs. 28/2016, derived from the European Directive 2013/51/Euratom. The radiological health risk for the population of the investigated area, due to the ingestion and inhalation of Rn-222 dissolved in water, was then evaluated by calculating the total annual effective dose, only in those cases where the parameter value was exceeded. The obtained results represent a main reference for the investigated area and are useful for determining any possible radiological health risk for human beings related to the ingestion of the investigated radionuclide. Moreover, they can also be used as a baseline for future investigations regarding background radioactivity levels. Full article

Significant efforts have been made by the International Commission on Radiological Protection (ICRP) to establish a reliable basis of equivalent and effective doses due to radionuclides. The ICRP over years has been updating the dose coefficients to include recent developments and make it more realistic. This perspective highlights some issues that warrant updating the methodology used for estimating ²¹⁰Po dose to humans. The need to underpin these dose coefficients with ever-increasing literature has encouraged us to share the observation on the significant loss of ²¹⁰Po due to seafood cooking, considering the loss due to cooking warrants changing the factor for the dose from seafood ingestion. Most dose assessment approaches use whole-body concentration, while most ²¹⁰Po is present in the liver and digestive system that often are not part of the edible portion. The other factor is the extremely high ²¹⁰Po concentration in aerosols as a result of coal and oil-fired power plants, forest fires, and volcanic activities, especially in the inhalable fraction. The ²¹⁰Po/²¹⁰Pb concentration ratio in the Gulf was observed to be between 1.6 and 1.9 in contrast to the 0.1 ratio observed in non-impacted areas. This reassessment of the inhalation dose is also relevant globally due to increasing incidences of forest fires where a much higher than 0.1 ²¹⁰Po/²¹⁰Pb ratio is expected and will result in a significant inhalation dose. Full article

We describe a school science outreach initiative that introduced learners to applied nuclear physics research by means of a two-day workshop that involved learners and teachers from 5 schools in the Western Cape province of South Africa. During this workshop, the participants were introduced to the naturally occurring, inert, colorless, and tasteless radioactive gas radon (²²²Rn). During the first day of the workshop, the participants were informed about the detrimental health impacts of inhaling radon and its daughter radionuclides and were shown how indoor radon activity concentrations can be measured using the electret ion chamber (EIC) technology. The learners were then each supplied with a short-term electret (E-PERM, Radelec, Frederick, MD, USA) and associated ion chamber to enable them to make radon measurements in their homes. The teachers in turn were supplied with EICs to enable them make radon measurements in their schools. The participants returned the EICs on the second day of the workshop, one week later. Here, the drop in the potential difference across each electret was measured in order to calculate the average indoor radon activity concentration. A total of 49 indoor radon concentrations were measured. The average indoor radon concentrations were 36 ± 26 Bqm⁻³ in homes and 41 ± 36 Bqm⁻³ in schools, while the highest concentration was found to be 144 Bqm⁻³. These levels were compared to predictions from a model that uses input information about the uranium content associated with the surface geology at each measurement location. The predictions compared well with the measured values. Full article

Human lung deposition data is non-mandatory for drug approval but very useful for the development of orally inhaled drug products. Lung deposition of inhaled drugs can be quantified by radionuclide imaging, for which one of the first considerations is the method used to radiolabel formulations. In this study, we report the development of a radiolabeling method for lyophilizate for dry powder inhalation (LDPI) formulations. TechneCoat^TM is one method that can radiolabel drug particles without using solvents. In this method, particles are radiolabeled with a dispersion of ^99mTc-labeled nanoparticles called Technegas^TM. Because a LDPI formulation is not comprised of particles but is a lyophilized cake aerosolized by air impact, the TechneCoat method cannot be used for the radiolabeling of LDPI formulations. We therefore modified the TechneCoat apparatus so that LDPI formulations were not aerosolized by the Technegas flow. Radiolabeling using a modified TechneCoat apparatus was validated with model LDPI formulations of interferon alpha (IFN). IFN of ^99mTc-unlabeled, IFN of ^99mTc-labeled, and ^99mTc of ^99mTc-labeled LDPI formulations showed similar behavior, and differences from IFN of ^99mTc-unlabeled LDPI formulations were within ±15% in aerodynamic particle size distribution measurement. Our radiolabeling method for LDPI formulations may be useful for the quantification of drug deposition in human lungs. Full article

This article contains and discusses the results of research on the source of polonium ²¹⁰Po and radio-lead ²¹⁰Pb in the human body of adults living in Poland. An adult inhabitant of Poland receives an effective annual radiation dose of 309 µSv from inhalation and absorption of ²¹⁰Po and ²¹⁰Pb. The main sources of both radionuclides in the body is cigarette and marijuana smoking. In terms of food, the consumption of fish, cereals, vegetables and fruit as well as mushrooms have the largest contribution to annual dose. This study highlights the importance of cigarette smoking and the growing importance of marijuana hash smoking as the main source of ²¹⁰Po and ²¹⁰Pb for adults living in Poland. The calculated dose that results from the decay of both radionuclides in body is 1/10 of the annual radiation dose received by a Polish inhabitant from natural sources (2.8 mSv) and is almost five times lower than the dose resulting from the inhalation of ²²²Rn. Full article

Radon (²²²Rn) is a natural radioactive gas formed in rocks and soil by the decay of its parent nuclide (238-Uranium). The rate at which radon migrates to the surface, be it along faults or directly emanated from shallow soil, represents the Geogenic Radon Potential (GRP) of an area. Considering that the GRP is often linked to indoor radon risk levels, we have conducted multi-disciplinary research to: (i) define local GRPs and investigate their relationship with associated indoor Rn levels; (ii) evaluate inhaled radiation dosages and the associated risk to the inhabitants; and (iii) define radon priority areas (RPAs) as required by the Directive 2013/59/Euratom. In the framework of the EU-funded LIFE-Respire project, a large amount of data (radionuclide content, soil gas samples, terrestrial gamma, indoor radon) was collected from three municipalities located in different volcanic districts of the Lazio region (central Italy) that are characterised by low to high GRP. Results highlight the positive correlation between the radionuclide content of the outcropping rocks, the soil Rn concentrations and the presence of high indoor Rn values in areas with medium to high GRP. Data confirm that the Cimini–Vicani area has inhalation dosages that are higher than the reference value of 10 mSv/y. Full article

A natural radioactivity in thermal water was investigated based on 19 selected thermal waters from Poland. The analysed results show that the radionuclides’ concentrations in the study waters vary over a wide range. The temperature of the waters varies from above 20 °C to above 80 °C. The waters are characterised by different mineralisation, chemical compositions, and belong to different hydrochemical types. There is a good correlation between the water temperature and the depths of the aquifer formations occurrence, suggesting the thermal energy originates from the thermal geogradient. The concentration of radium is well correlated with the water mineralisation. The ratio of radium activity (²²⁶Ra/²²⁸Ra) in groundwater relates not only the ratio of uranium activity to that of thorium (²³⁸U/²³²Th) in aquifer formation, but also depends on the physical and chemical water properties. Based on the concentration of radon and its transport model, the radiation exposures due to inhalation of ²²²Rn and its progeny for employees and clients of the spa were assessed. The use of the thermal waters as a drinking resource may be problematic due to the possibility of exceeding the recommended annual committed effective dose 0.1 mSv. Full article

Natural radionuclide concentrations in coal and coal ash can occur at levels sufficient to raise potential health and environmental concerns when (re)suspended or disposed into the environment. To evaluate such concerns, this study characterized coal and simulant coal ash samples obtained from two Nigerian coal mines (Okaba and Omelewu) using high resolution gamma spectroscopy combined with scanning electron microscopy and energy dispersive spectroscopy. Discrete uraninite particles were observed dispersed within the coal ash samples, alongside U and Th containing mineral grains (monazite and zircon) with monazite the most abundant radioactive mineral particles. The pitted and cracked surface morphologies of these radioactive particles (with sizes between 10 μm and 80 μm) indicate their susceptibility for disintegration into more harmful and readily inhalable PM2.5 aerosol particles, with the potential to deliver a localized dose and cause chronic respiratory diseases. The results of activity concentrations and radiological hazard indices for the coal ash samples from both mines were between three and five times higher than world average in soil, which imply that these coal ash materials should be suitably contained in slurry ponds to prevent hazards due to increased risk of prolonged indoor exposure to gamma radiation, radon gas, and inhalation of liberated radioactive particles. Full article

Identifying sources of concern and risk from shale gas development, particularly from the hydraulic fracturing process, is an important step in better understanding sources of uncertainty within the industry. In this study, a risk assessment of residential exposure pathways to contaminated drinking water is carried out. In this model, it is assumed that a drinking water source is contaminated by a spill of flowback water; probability distributions of spill size and constituent concentrations are fit to historical datasets and Monte Carlo simulation was used to calculate a distribution of risk values for two scenarios: (1) use of a contaminated reservoir for residential drinking water supply and (2) swimming in a contaminated pond. The swimming scenario did not produce risks of concern from a single exposure of 1 h duration, but 11 such 1-h exposures did produce risks of 10⁻⁶ due to radionuclide exposure. The drinking water scenario over a 30-year exposure duration produced cancer risk values exceeding 10⁻⁶ for arsenic, benzene, benzo(a)pyrene, heptachlor, heptachlor epoxide, pentachlorophenol, and vinyl chloride. However, this extended exposure duration is probably not realistic for exposure by a spill event. Radionuclides produced risks in the residential drinking water scenario of 10⁻⁶ in just 8 h, a much more realistic timeline for continual exposure due to a spill event. In general, for contaminants for which inhalation exposure was applicable, this pathway produced the highest risks with exposure from ingestion posing the next greatest risk to human health followed by dermal absorption (or body emersion for radionuclides). Considering non-carcinogenic effects, only barium and thallium exceed target limits, where the ingestion pathway seems to be of greater concern than dermal exposure. Exposure to radionuclides in flowback water, particularly through the inhalation route, poses a greater threat to human health than other contaminants examined in this assessment and should be the focus of risk assessment and risk mitigation efforts. Full article

This manuscript evaluates the role of cell killing, tissue disorganization, and tissue damage on the induction of lung cancer following low dose rate radiation exposures from internally deposited radioactive materials. Beagle dogs were exposed by inhalation to ⁹⁰Y, ⁹¹Y, ¹⁴⁴Ce, or ⁹⁰Sr in fused clay particles. Dogs lived out their life span with complete pathology conducted at the time of death. The radiation dose per cell turnover was characterized and related to the cause of death for each animal. Large doses per cell turnover resulted in acute death from lung damage with extensive cell killing, tissue disorganization, chronic inflammatory disease, fibrosis, and pneumonitis. Dogs with lower doses per cell turnover developed a very high frequency of lung cancer. As the dose per cell turnover was further decreased, no marked tissue damage and no significant change in either life span or lung cancer frequency was observed. Radiation induced tissue damage and chronic inflammatory disease results in high cancer frequencies in the lung. At doses where a high frequency of chromosome damage and mutations would be predicted to occur there was no decrease in life span or increase in lung cancer. Such research suggests that cell killing and tissue damage and the physiological responses to that damage are important mechanisms in radiation induced lung cancer. Full article

We estimate the contamination risks from the atmospheric dispersion of radionuclides released by severe nuclear power plant accidents using the ECHAM/Modular Earth Submodel System (MESSy) atmospheric chemistry (EMAC) atmospheric chemistry-general circulation model at high resolution (50 km). We present an overview of global risks and also a case study of nuclear power plants that are currently under construction, planned and proposed in the Eastern Mediterranean and Middle East, a region prone to earthquakes. We implemented continuous emissions from each location, making the simplifying assumption that all potential accidents release the same amount of radioactivity. We simulated atmospheric transport and decay, focusing on ¹³⁷Cs and ¹³¹I as proxies for particulate and gaseous radionuclides, respectively. We present risk maps for potential surface layer concentrations, deposition and doses to humans from the inhalation exposure of ¹³¹I. The estimated risks exhibit seasonal variability, with the highest surface level concentrations of gaseous radionuclides in the Northern Hemisphere during winter. Full article

The radioactivity in tobacco leaves collected from 15 different regions of Greece and before cigarette production was studied in order to find out any association between the root uptake of radionuclides from soil ground by the tobacco plants and the effective dose induced to smokers from cigarette tobacco due to the naturally occurring primordial radionuclides , such as ²²⁶Ra and ²¹⁰Pb of the uranium series and ²²⁸Ra of the thorium series and/or man-made radionuclides, such as ¹³⁷Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the activities of the radioisotopes of radium, ²²⁶Ra and ²²⁸Ra in the tobacco leaves reflected their origin from the soil by root uptake rather than fertilizers used in the cultivation of tobacco plants. Lead-210 originated from the air and was deposited onto the tobacco leaves and trapped by the trichomes. Potassium-40 in the tobacco leaves was due to root uptake either from soil or from fertilizer. The cesium radioisotopes ¹³⁷Cs and ¹³⁴Cs in tobacco leaves were due to root uptake and not due to deposition onto the leaf foliage as they still remained in soil four years after the Chernobyl reactor accident, but were absent from the atmosphere because of the rain washout (precipitation) and gravitational settling. The annual effective dose due to inhalation for adults (smokers) for ²²⁶Ra varied from 42.5 to 178.6 μSv/y (average 79.7 μSv/y), while for ²²⁸Ra from 19.3 to 116.0 μSv/y (average 67.1 μSv/y) and for ²¹⁰Pb from 47.0 to 134.9 μSv/y (average 104.7 μSv/y), that is the same order of magnitude for each radionuclide. The sum of the effective doses of the three radionuclides varied from 151.9 to 401.3 μSv/y (average 251.5 μSv/y). The annual effective dose from ¹³⁷Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 nSv/y (average 199.3 nSv/y). Full article