Soil erosion is one of the largest global problems of environmental protection and sustainable development, causing serious land degradation and environmental deterioration. The need for fast and accurate soil rate assessment of erosion and deposition favors the application of alternative methods based on the radionuclide measurement technique contrary to long-term conventional methods. In this paper, we used gamma spectrometry measurements of ¹³⁷Cs and unsupported ²¹⁰Pb _ex in order to quantify the erosion on the Titel Loess Plateau near the Tisa (Tisza) River in the Vojvodina province of Serbia. Along the slope of the study area and in the immediate vicinity eight representative soil depth profiles were taken and the radioactivity content in 1 cm thick soil layers was analyzed. Soil erosion rates were estimated according to the profile distribution model and the diffusion and migration model for undisturbed soil. The net soil erosion rates, estimated by ¹³⁷Cs method range from −2.3 t ha⁻¹ yr⁻¹ to −2.7 t ha⁻¹ yr⁻¹, related to the used conversion model which is comparable to published results of similar studies of soil erosion in the region. Vertical distribution of natural radionuclides in soil profiles was also discussed and compared with the profile distribution of unsupported ²¹⁰Pb _ex measurements. The use of diffusion and migration model to convert the results of ²¹⁰Pb _ex activities to soil redistribution rates indicates a slightly higher net erosion of −3.7 t ha⁻¹ yr⁻¹ with 98% of the sediment delivery ratio.

It is well known that protection from the external irradiation produced by beta emitters is simpler than the corresponding shielding of radioactive sources that emit gamma radiation. This is caused by the relatively strong absorption (i.e. short range) of electrons in different materials. However, for strong beta sources specific attention should be paid to the bremsstrahlung radiation induced in the source encapsulation (matrix), especially for emitters with relatively high beta-endpoint energy (1 MeV) that are frequently used in nuclear medicine. In the present work, the bremsstrahlung spectra produced in various materials by the following beta emitters, Sr-90 (together with its daughter Y-90), P-32 and Bi-210, were investigated by Monte Carlo simulations using Geant4 software. In these simulations, it is supposed that the point radioactive sources are surrounded by cylindrically shaped capsules made from different materials: Pb, Cu, Al, glass and plastic. For the case of Y-90(Sr-90) in cylindrical lead and aluminum capsules, the dimensions of these capsules have also been varied. The absorbed dose rates from bremsstrahlung radiation were calculated for cases where the encapsulated point source is placed at a distance of 30 mm from the surface of a water cylinder with a mass of 75 kg (approximately representing the human body). The bremsstrahlung dose rate and bremsstrahlung spectrum from the Y-90(Sr-90) point source encapsulated in an Al capsule were also measured experimentally and compared with the corresponding simulation results. In addition, the bremsstrahlung radiation risk for medical staff in therapies using Y-90 was considered in simulations, relating to finger dose as well as whole-body dose during preparation and injection of this radioisotope. The corresponding annual doses were obtained for medical workers for specified numbers of Y-90 applications to patients.

Exposure to ionizing radiation originates primarily from terrestrial and cosmic radiation sources. Cosmic-radiation exposure depends strongly on altitude and is additionally influenced by latitude and solar activity. Particular attention should be paid to aircraft passengers and aircrew, who may receive elevated radiation doses due to prolonged exposure at flight altitudes. In this study, Monte Carlo simulations were performed using the Geant4 toolkit (version 11.3) to investigate secondary cosmic-ray particles, including muons, neutrons, protons, electrons/positrons, and gamma photons, at altitudes of 0 m, 2100 m, and 11,300 m and latitudes of 0°, 30°, 45°, 60°, and 90°. Deposited energies in a water phantom representing the human body were used to calculate equivalent dose rates and estimate annual effective doses. The average equivalent dose rates were 0.036, 0.22, and 6.9 μSv·h⁻¹ at 0 m, 2100 m, and 11,300 m, respectively. Dose rates showed a pronounced latitude dependence, increasing from low latitudes and reaching maximum values at 60°, followed by a decrease at 90°, consistent with the reported latitude effect of cosmic radiation. The annual effective dose for the general population at sea level ranged from 0.28 to 0.35 mSv, with an average of 0.31 mSv. For annual flight times of 10, 50, and 100 h, passenger doses were 0.069, 0.34, and 0.69 mSv, respectively, remaining below 1 mSv. For aircrew, annual doses were 3.44, 4.82, and 6.19 mSv for 500, 700, and 900 flight hours, respectively, remaining below 20 mSv. The results are consistent with literature data and demonstrate the applicability of Monte Carlo simulations for cosmic-radiation exposure assessment.