Indoor radon (222Rn), thoron (220Rn) and their progeny concentrations have been measured in different types of buildings at different locations in different dwellings in different seasons in Hassan city, Karnataka, using time-integrated passive radon dosemeters containing LR-115 Type II solid-state nuclear track detectors. The annual effective dose due to radon and thoron has been estimated. The activity concentrations were observed to be highest in winter and lowest in summer, and the data also shows that bathrooms and kitchens have significantly higher radon-thoron concentrations and annual effective doses.

The noble radioactive gas radon and its isotope thoron dominate terrestrial radiation in the indoor environment. These gases eventually disintegrate generating radioactive ions that readily adhere to aerosol particles. This study was conducted in a tectonically active location with significant radon concentrations. The obtained average values of radon mass exhalation and thoron surface exhalation rate from this study are higher than the global average values of 56 mBq kg-1 h-1 and 1000 mBq m-2 s-1, respectively. As the exhalation rates are higher, naturally the average radon and thoron concentrations are also greater than the worldwide average values of 40 and 10 Bq m-3, respectively. No significant correlation was observed between 222Rn and 220Rn exhalation rate and indoor 222Rn/220Rn concentration. The exposure dose due to 222Rn, 220Rn and their progenies shows no significant health risk.

Following the Fukushima Daiichi Nuclear Power Plant disaster in March 2011, the Japanese government initiated an unprecedented decontamination programme to remediate 137Cs-contaminated soils and allow population return. This programme involved the removal of topsoil under farmland and residential land, and its replacement with \"fresh soil\" composed of granitic saprolite. However, decontamination was limited to these two land uses, without remediating forests, which cover 70 % of the surface area in the affected region. In this unprecedented context, the specific impact of this unique decontamination programme on 137Cs transfers in river systems remains to be quantified at the catchment scale. In this study, based on the analysis of a sediment core collected in June 2021 in the Mano Dam reservoir draining a decontaminated catchment, the effects of soil decontamination on particle-bound 137Cs dynamics and sediment source contributions in response to a succession of extreme precipitation events were retrospectively assessed. The sequence of sediment layer deposition and its chronology were reconstructed through the analysis of several diagnostic properties (organic matter, elemental geochemistry, visible colourimetry, granulometry) and contextual information. During abandonment (2011-2016), cropland contribution decreased (31 %). Concurrently, 137Cs activity and deposition flux decreased (19 and 29%year-1, respectively). Following decontamination (2017), sediment transfer increased (270 %) in response to increased contributions from decontaminated cropland and \"fresh soil\" (625 % and 180 % respectively). Meanwhile, forest contributions remained stable. In contrast, 137Cs activity dropped (65 %), although 137Cs deposition flux remained constant. Forests acted as a stable source of 137Cs. Accordingly, 137Cs deposition flux after decontamination (2016-2021) was similar to that observed during the 5-years period of land abandonment (2011-2016), as a result of the regrowth of spontaneous vegetation over farmland, protecting soil against erosion. Future research should further investigate the impact of longer land abandonment that prevailed in some regions decontaminated lately on the 137Cs fluxes in the rivers.

A De-Pangher-type long counter was designed for neutron measurements in standard neutron fields based on the results of simulations using the MCNP6 code at the National Metrology Institute of Japan, the National Institute of Advanced Industrial Science and Technology. The effects of six parameters in the design on the energy response of the long counter were investigated. The energy response was then quantitatively evaluated for eight design candidates selected from the investigation. The calculation results show that these candidates have a flatter energy response from 100 eV to 10 MeV compared to that of the current long counter. These candidates also reduce the difference between the average energy response from 10 eV to 1 MeV and that from 10 to 20 MeV.

An accident at the Barakah Nuclear Power Plant (BNPP) would result in a significant radionuclide release into the semi-closed marine environment. In this research, the released radionuclide distribution pattern and dose rate in the Persian/Arabian (Gulf) were calculated using a combined hydrodynamic/radiobiological model. Simulations of the dispersion of artificial radionuclide concentrations were conducted using a HYSPLIT model. To assess prospective hazards in case of an incident, environmental risk from ionizing contaminants: assessment and management (ERICA) tools were used. Using the Fukushima nuclear power accident as a model, the scenario source term profile was developed. The volumetric concentrations levels of pollutants ranged between 1 × 104 mBq m-3 to 1 × 1010 mBq m-3 in the radius of 200 km after 48 h. Based on the dose rates of the various marine biotas, Polychaete worms, and Pelagic fish, they had the highest and lowest dose contribution.

The integration of the ORION digital signal processing-based MCA system coupled with a 3″ × 3″ NaI(Tl) detector assembly with a GM detector for counting beta (β) has eliminated the need for a standalone β-γ method in which U3O8 is determined by gross β and gross γ counting. Uraniferous and mixed U-Th samples were taken up for study and compared with the results obtained from Canberra p-type coaxial high resolution gamma ray spectrometry detector. In uraniferous samples, U3O8 values obtained are within ±10%, whereas in the case of mixed U-Th samples, U3O8 values are within ±15%. Regression graphs drawn between the outcomes from the two analytical systems indicate R2 > 0.95 for Ra(eU3O8) and ThO2. In uraniferous samples, the R2 value for U3O8 was found to be > 0.99, but in mixed U-Th samples, it is 0.92. The closeness of agreement between the results obtained from two methods at various concentrations over the analytical range shows that the integrated system is suitable for the quantitative determination of eU3O8, U3O8, Ra(eU3O8), ThO2 and K in geological rock samples.

It has been found that algae have a variety of health benefits, although investigations showed that they contain radiotoxic elements, including 226Ra, 232Th, 40K, and 137Cs, which may affect human health. This study is connected to activity concentration measurements of the above radionuclides in the algae supplements available in the Middle East markets. The annual effective radiation doses of measured radionuclides in analyzed algal supplements have been calculated. The highest values of annual effective doses have been estimated for 226Ra in Ecklonia (13.39 μSv/y) and for 232Th in Red Marine Algae (11.80 μSv/y), both from South Korea. In algal \"superfoods\", the effective dose of 137Cs is not significantly affected by the Fukushima Nuclear Power Plant. Based on these results, it can be concluded that the activity levels of radionuclides are low, the naturally occurring radionuclides provide the most effective doses, and algae supplements can be considered safe.

Accidental release of radiocaesium (137Cs) from nuclear power plants may result in long-term contamination of environmental and food production systems. Assessment of food chain contamination with 137Cs relies on 137Cs soil-to-plant transfer data and models mainly available for regions affected by the Chornobyl and Fukushima accidents. Similar data and models are lacking for other regions. Such information is needed given the global expansion of nuclear energy. We collected 38 soils worldwide of contrasting parent materials and weathering stages. The soils were spiked with 137Cs and sown with ryegrass in greenhouse conditions. The 137Cs grass-soil concentration ratio varied four orders of magnitude among soils. It was highest in Ferralsols due to the low 137Cs interception potential of kaolinite clay and the low exchangeable potassium in these soils. Our results demonstrate, for the first time, the high plant uptake of 137Cs in tropical soils. The most recent 137Cs transfer model, mainly calibrated to temperate soils dominated by weathered micas, poorly predicts the underlying processes in tropical soils but, due to compensatory effect, still reasonably well predicts 137Cs bioavailability across all soils (R2 = 0.8 on a log-log scale).

According to UNSCEAR, cosmic radiation contributes to ~16% (0.39 mSv/y) of the total dose received by the public at sea level. The exposure to cosmic rays at a specific location is therefore a non-negligible parameter that contributes to the assessment of the overall public exposure to radiation. In this study, simulations were conducted with the Particle and Heavy Ion Transport code System, a Monte Carlo code, to determine the fluxes and effective dose due to cosmic rays received by the population of Douala. In minimum solar activity, the total effective dose considering the contribution of neutron, muon+, muon-, electron, positron and photon, was found to be 0.31 ± 0.02 mSv/y at the ground level. For maximum solar activity, it was found to be 0.27 ± 0.02 mSv/y at ground level. During maximum solar activity, galactic cosmic rays are reduced by solar flares and winds, resulting in an increase in the solar cosmic-ray component and a decrease in the galactic cosmic-ray component on Earth. This ultimately leads to a decrease in the total cosmic radiation on Earth. These results were found to be smaller than the UNSCEAR values, thus suggesting a good estimation for the population of Douala city located near the equatorial line. In fact, the cosmic radiation is more deflected at the equator than near the pole. Muons+ were found to be the main contributors to human exposure to cosmic radiation at ground level, with ~38% of the total effective dose due to cosmic exposure. However, electrons and positrons were found to be the less contributors to cosmic radiation exposure. As regards the obtained results, the population of Douala is not significantly exposed to cosmic radiation.

Coastal Mangroves are facing growing threats due to the harmful consequences of human activities. This first-ever detailed study of natural radioactivity in soil samples collected from seven tourist destinations within the Sundarbans, the world\'s largest mangrove forest, was conducted using HPGe gamma-ray spectrometry. Although the activity levels of 226Ra (11 ± 1-44 ± 4 Bq/kg) and 232Th (13 ± 1-68 ± 6 Bq/kg) generally align with global averages, the concentration of 40K (250 ± 20-630 ± 55 Bq/kg) was observed to surpass the worldwide average primarily due to factors like salinity intrusion, fertilizer application, agricultural runoff, which suggests the potential existence of potassium-rich mineral resources near the study sites. The assessment of the hazard parameters indicates that the majority of these parameters are within the recommended limits. The soil samples do not pose a significant radiological risk to the nearby population. The results of this study can establish important radiological baseline data before the Rooppur Nuclear Power Plant begins operating in Bangladesh.