The aim of this work was to estimate the health and radiation hazard due to external irradiation from terrestrial radionuclides in the Stara planina Mt. region, which is important because of past uranium mining activities on the mountain. Soil samples were collected inside the flotation processing facilities, their surroundings and more distant locations, i.e. from areas considered certainly affected, potentially affected, and unaffected by former mining and uranium ore processing activities. The radiological and health risk assessments were done by calculating the six main parameters, based on the activity concentration of 238U, 232Th, and 40K in soil samples as determined by gamma-ray spectrometry. Increased values of the risk parameters were observed only for sites where uranium ore was processed, while the location surrounding these compounds showed values that are usual for this mountain or slightly above them. Calculations of the risk parameters for the background area showed no radiation risk for the local and seasonal population. The presence of U and Th was detected in all water samples from creeks surrounding the facilities, but only in the water from the facility drainage pipe did their concentration exceed the limits given for the uranium content in drinking water. In conclusion, the results obtained in this study fall within the range of values in similar studies conducted worldwide and are below the values which can cause a significant radiation hazard.

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.

This study aims to obtain data on terrestrial radioactivity coming from naturally occurring (40K, 226Ra, 232Th, and 238U) and artificial (137Cs) radionuclides in surface soil (0-10 cm) of selected eighteen public-access urban areas in Krusevac city, Serbia, and to assess the corresponding health effects for citizens using those areas for recreational purposes. The specific activities of investigated radionuclides were analyzed using HPGe gamma-ray spectrometry. The mean specific activity of 40K, 226Ra, 232Th, 238U, and 137Cs was found to be 353, 39.8, 38.9, 41.0, and 5.9, respectively, in compliance with their values in other parts of Serbia and neighboring countries reported in similar researches. To evaluate the human health risk associated with radionuclides, conservative exposure assumptions and models recommended by the United States Environmental Protection Agency were employed taking into account three exposure routes: ingestion, inhalation of soil, and external irradiation. The absorbed gamma dose rate in the air due to natural radionuclides in soil was calculated. The calculated indices suggested that the radiation risk arising from natural and artificial radionuclides was not significant. The total excess lifetime cancer based on the 95 % upper confidence limit of the specific activities mean was calculated to be 5.89?10?6, lower than the tolerable risk for regulatory purposes (10?4). Among investigated radiation exposure pathways, external exposure was the most contributing one for the health risk. The results obtained for the city's parks and playgrounds suggested their safe use for recreational purposes from the radioecological point of view.

A handheld Raman spectrometer was used as a sensor for the detection of ammonium nitrate (NH4NO3, AN), fuel oil (FO), AN-water solutions, and AN-soil mixtures deposited on materials such as glass and tape to simulate the field conditions of explosive detection. AN is an inorganic oxidizing salt that is commonly used in mining explosives. A significant explosive mixture is Ammonium nitrate-fuel oil (ANFO). However, owing to its widespread accessibility, AN-based explosives are also utilized for the manufacture of improvised explosive devices (IEDs). The portable Raman system with a laser operating at 785 nm wavelength is used to analyze simulated sites manipulated with IEDs. Characteristic Raman bands from AN were found at 710 cm-1 and 1050 cm-1 , and 1440-1470 cm-1 for FO. The relative limit of detection of AN in water was less than 0.1%.

The potential consequences of a nuclear security event could be catastrophic; therefore, all appropriate measures should be taken to prevent them. Detection, as one of nuclear security's functions, involves recognizing criminal or unauthorized acts with nuclear security implications, or measurements indicating the unauthorized presence of nuclear or other radioactive material at associated facilities, activities, or strategic locations. Determining natural background radiation in advance for such locations can certainly enhance the effectiveness of nuclear security detection architecture. In this research, measurements of natural background radiation were conducted at 324 points evenly distributed throughout the City of Kruševac, Serbia, including locations and objects most vulnerable to exploitation by potential adversaries. The ambient dose equivalent rate was determined using a handheld radioisotope identification device based on scintillation gamma spectroscopy and mapped using geostatistical software. The measured dose rates fell within the expected ranges for Serbia, as well as for the broader region and worldwide. No orphan sources were detected. Statistical tests indicated a significant difference in dose rate values between paved and unpaved urban surfaces. Furthermore, the most common false positives in radioisotope identification were ascertained. It is concluded that utilizing the methodology applied in this work for collecting readings and spectra on natural background radiation proved to be a cost-efficient means of facilitating the assessment of alarms or alerts, as well as detecting the presence of suspicious or unauthorized nuclear or radioactive material in the environment.