The specific activities of natural radionuclides (⁴⁰K, ²²⁶Ra and ²³²Th) and Chernobyl-derived ¹³⁷Cs were measured in soil profiles representing typical soil types of Belgrade (Serbia): chernozems, fluvisols, humic gleysols, eutric cambisols, vertisols and gleyic fluvisols. The influence of soil properties and content of stable elements on radionuclide distribution down the soil profiles (at 5 cm intervals up to 50 cm depth) was analysed. Correlation analysis identified associations of ⁴⁰K, ²²⁶Ra and ¹³⁷Cs with fine-grained soil fractions. Significant positive correlations were found between ¹³⁷Cs specific activity and both organic matter content and cation exchange capacity. Saturated hydraulic conductivity and specific electrical conductivity were also positively correlated with the specific activity of ¹³⁷Cs. The strong positive correlations between ²²⁶Ra and ²³²Th specific activities and Fe and Mn indicate an association with oxides of these elements in soil. The correlations observed between ⁴⁰K and Cr, Ni, Pb and Zn and also between ¹³⁷Cs and Cd, Cr, Pb and Zn could be attributed to their common affinity for clay minerals. These results provide insight into the main factors that affect radionuclide migration in the soil, which contributes to knowledge about radionuclide behaviour in the environment and factors governing their mobility within terrestrial ecosystems.

This study evaluates the influence of the largest Serbian coal-fired power plant on radionuclide concentrations in soil profiles up to 50 cm in depth. Thirty soil profiles were sampled from the plant surroundings (up to 10 km distance) and analyzed using standard methods for soil physicochemical properties and gamma ray spectrometry for specific activities of natural radionuclides (40K, 226Ra and 232Th). Spatial and vertical distribution of radionuclides was determined and analyzed to show the relations between the specific activities in the soil and soil properties and the most influential factors of natural radionuclide variability were identified. The radiological indices for surface soil were calculated and radiological risk assessment was performed. The measured specific activities were similar to values of background levels for Serbia. The sampling depth did not show any significant influence on specific activities of natural radionuclides. The strongest predictor of specific activities of the investigated radionuclides was soil granulometry. All parameters of radiological risk assessment were below the recommended values and adopted limits. It appears that the coal-fired power plant does not have a significant impact on the spatial and vertical distribution of natural radionuclides in the area of interest, but technologically enhanced natural radioactivity as a consequence of the plant operations was identified within the first 1.5 km from the power plant.

The health effects attributed to exposure to ambient PM2.5 concentrations above 10 ?g/m3 by using the AirQ+ modeling software were assessed. The hourly concentrations of PM2.5 were collected from 13 air pollution monitoring stations in the Belgrade district during June and July 2021., which were further used as input data for the AirQ+ software. The average concentration of PM2.5 for two-month monitoring from all sampling sites in the city was 14.8 ?g/m3, the maximum daily concentration was 55.7 ?g/m3, while the maximum concentration per hour was 365 mg/m3. The spatial distribution of concentrations was mapped using geostatistical interpolation, revealing hotspots within the city center and industrial area of the district. The burden of disease, such as stroke, ischemic heart disease (IHD), chronic obstructive pulmonary disease (COPD), and lung cancer, due to the ambient PM2.5 pollution was evaluated according to the WHO method-ology for health risk assessment of air pollution. The model used for this assessment is based on the attributable proportion defined as the section of the health effect related to exposure to air pollution in an at-risk population. The estimated attributable proportion was 19.4% for stroke, 27.2% for IHD, 15.3% for COPD and 9.0% for lung cancer. The estimated number of attributable cases per 100000 population at risk, due to PM2.5 air pollution, for stroke, IHD, COPD, and lung cancer, was 28, 34, 15, and 8, respectively.