The aim of this work was to prove the use of radionuclides deposited in sediment core taken from an overgrowing dystrophic lakes surrounded by marsh-peat vegetation to estimate sedimentary conditions. Sediment core samples were taken from the Toporowe Stawy Lakes (Niżni (TSN) and Wyżni (TSW); Tatra Mountains). The sampling was done using a Limnos corer. After the physical sample preparations, gamma measurements were performed. Radiochemical analysis was applied with the aim of determining 210Pb radioactivity by means of 210Po. The mean values for TSN lake are as follows: 137Cs ~ 123 Bq∙kg-1, 40 K ~ 389 Bq∙kg-1, 228Th ~ 55 Bq∙kg-1, 226Ra ~ 86 Bq∙kg-1, 241Am ~ 5 Bq∙kg-1, and 210Pbuns ~ 180 Bq∙kg-1. For TSW lake, the radioactivity levels of 226Ra and 241Am are comparable to the TSN. The mean values of 137Cs, 40 K, and 228Th are almost twice as high as in TSN. The level of 210Pb in uppermost layer of TSN is higher than in TSW. Sediments were dated by use of 210Pb method, and the rate of sedimentation of each layer was also estimated. Basic chemometric tools were used to confirm the way of deposition of radionuclide, find the correlations between variables, and compare analyzed lakes. It was concluded that the presented type of lakes are a valuable source of information and the vertical distribution of radionuclide can be used to interpret the source of material supply and factors that influence the sedimentation process in recent 150-200 years.

In this study, two software tools, namely the ERICA Assessment Tool and the RESRAD-BIOTA code, are used for the calculation of the radiological exposure of non-human organisms. For the purposes of the analysis, data retrieved from field studies are used. The site-specific measurements were performed on organisms (mammals-sheep and goats of Bovidae spp.) collected from free-ranged grazing regions in Greece. Plants (grass) of Poaceae spp. and soil samples were also collected from these regions. Natural radionuclides (226Ra, 228Ra, and 228Th) of lithogenic origin and 137Cs, resulted from human activities (Chernobyl and Fukushima nuclear power plant accidents and global fallout), were detected in all samples. The measured activity concentrations were used as input to the two software tools, the ERICA Assessment Tool and the RESRAD-BIOTA code. The results of the simulations provided the external, internal, and total dose rates received by the organisms due to the exposure to the radionuclides. The assessments indicated that out of all detected radionuclides, 228Th is the main contributor to the external dose and 226Ra and 228Ra are the main contributors to the internal dose. The comparative analysis of the two tools revealed significant differences in the calculated doses. In fact, external and internal doses calculated by RESRAD-BIOTA are higher than the values calculated by the ERICA Tool, due to the dose conversion coefficients (DCCs) used for the dose calculation. RESRAD-BIOTA provides more conservative values, but ERICA Tool provides lower uncertainty due to the higher flexibility in the design of the phantom organism. On a risk assessment basis, there is no significant impact, due to organisms\' exposure to radioactivity. However, further consideration of the exposure levels is required due to the potential effects of protracted low-level ionizing radiation on the various levels of life\'s organization.