The current radioecological situation in the areas of the “Chernobyl footprint” in Russia: 40 years later

Four decades after the Chernobyl accident, the assessment of the long-term effects of radioactive en-vironmental pollution remains relevant. The present study provides a comprehensive analysis of the current radioecological situation (as of January 2025) in the areas of the emergency trace with an em-phasis on the most radioactively contaminated territories in the Bryansk, Kaluga, Tula and Oryol regions. Estimates for background territories in the Novgorod region are also presented for comparison. The work is based on data from long-term monitoring conducted by Research and Production Association “Typhoon” of the Russian Federal Service for Hydrometeorology and Environmental Monitoring. The study found that the main dose-forming radionuclide in the vast majority of the emergency trace is long-lived 137Cs, which contributes to the integral contamination index (ICI) of soil from 78% to 100%. The contribution of the 90Sr to the ICI is an order of magnitude smaller. The dose rate and the environmental risk index were estimated for some reference species of terrestrial biota. It has been established that the current values of the radiation dose rate of the considered biota species, determined by the average density of soil contamination with radionuclides in the areas under consideration, satisfy the maximum permissible radiation load. It is shown that the highest dose loads for reference species are preserved in the Bryansk region. A steady positive trend in improving the radiation situation has been revealed. Over the past five years (2020-2025), the number of settlements in 137Cs pollution zones with a density of 15-40 Ci/km2 has decreased by more than 2 times, and the values of ICI have decreased by an average of 1.2 times. In the long term (from 1986 to 2025), the radiation dose rate of biota in the most radionuclide contaminated areas decreased by 20-30 times, and the ICI values decreased by 3.5 times. Despite the significant improvement in the radiation situation, the continued spatial heterogeneity of pollution and the potential risk to the most radiosensitive species necessitate continued radioecological monitoring in the territories of the emergency trace.