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The aim of the study is to analyze the accumulated data on the study of forest territories of the border regions of the Bryansk region that have been exposed to radioactive contamination for their involvement in economic activity, as well as the possible transfer of radioactive materials in forest fires. The area of recorded and unaccounted forests was estimated according to the “Forest Plan of the Bryansk Region for the period 2019-2028” and the results of the analysis of remote sensing data of the earth, the assessment of radiation pollution – according to the radiation surveys of the forest fund and radioecological monitoring of forests, assessment of cesium-137 content – according to radiation monitoring. In the course of the work, the dynamics of the transition of forests from the range of a high level of radioactive contamination to lower ones from 1991 to 2018 slightly changes the total area of contaminated forests by regions was revealed. Top-level values of cesium-137 content in the main types of forest combustible materials, which a dangerous factor is contributing to a significant increase in the content of radiocesium in atmospheric air and the transfer of radionuclides beyond the limits of radioactive contamination zones in a forest fire. The most radiation-hazardous is the forest litter, which contains more than 70% of the total cesium-137 reserve in forest combustible materials, the values of which reach values of 224 kBq / kg in the Krasnogorsk district of the Bryansk region. The obtained forecast of cesium-137 content in the forest litter by the zones of radioactive contamination of forests in the most polluted areas of the Bryansk region for the period up to 2046 indicates the preservation of a high degree of radioactive contamination of forests in the Krasnogorsk and Novozybkovsky districts after more than 60 years after the Chernobyl accident power plants. Due to the high class of natural fire hazard of forests in the south-west of the Bryansk region and the high risk of fires in contaminated areas, it is necessary to assess the degree of danger in the prevention and suppression of radioactive forest fires, especially criterion of the absorbed dose for workers in order to avoid the deterministic effect.

The aim of this study was to analyze the current radioecological situation in agriculture in five south-west districts of the Bryansk region, which were exposed to the most radiation influence due to the accident at the Chernobyl NPP. Currently, there are 135 collective farms in the observed areas. The total area of agricultural lands was 266.2 thousand hectares. The area of agricultural lands with 137Cs contamination over 37 kBq/m2 was 244.8 thousand hectares in 2018. The area of arable land, hay fields and pastures located in the zone with a 137Cs soil surface activity in a range of 37–185 kBq/m2 is 135.1 thousand hectares, 185–555 kBq/m2– 88.3 thousand hectares, 555-1480 kBq/m2 – 19.8 thousand hectares. At present, only 21.4 thousand hectares (8% of the agricultural lands in the considered areas) don’t exceed contamination levels of 137Cs 37 kBq/m2, and they can be classified as “clean territory”. Analysis of the agricultural products radiation monitoring data from the collective farms of the south-west districts of the Bryansk region showed that the part of feed and crop products exceeded the standards varied from 4 to 15% in 2017-2018. The high content of 137Сs in the feed of several collective farms determined the excess of sanitary and hygienic standards in livestock products from these farms – milk in 4-8% of total samples, beef in 5–8% of total samples. The collective farms located in Krasnogorsky and Novozybkovsky districts of the Bryansk region, with a high risk of exceeding the standards for the content of radionuclides in the agricultural products, was identified. The required volumes of rehabilitation measures in the plant growing and animal husbandry of the south-west districts of the Bryansk region was indicated. It was found that 75 thousand hectares of the total area of agricultural lands need radical improvement and the introduction of higher doses of agromeliorants to produce plant-growing and fodder products corresponding to the legislation standards. To produce milk and beef that comply with sanitary and hygienic standards for livestock products, it is necessary to use ferrocyanide treatment in volumes of 10.5 t/a. It was shown that most radioactively contaminated rural areas need individual programs for the application of rehabilitation technologies. Such programs should provide the population safety and domestic activity. 

The aim of this study was to determine the dynamics of decrease of the dose rate of gamma radiation in air from 137Cs in typical rural locations in the remote period after the Chernobyl accident. The dose rate measurements were performed in the areas of 15 settlements of the Zlynka, Klintsy and Novozybkov districts of the Bryansk region of Russia in the period 1998–2012. After the accident in 1986, the density of contamination of the territory with 137Cs in all settlements was higher than the value of 555 kBq/m2 . Monitoring measurements of the dose rate were performed in eight locations commonly used in assessing the radiation doses to the rural population after the Chernobyl accident: 1) virgin soils (meadows) located outside settlements, 2) virgin soils located inside settlements, 3) forests, 4) arable fields, 5) kitchen gardens, 6) other ground surfaces (earthen yards next to residential buildings), 7) single-story wooden houses, 8) asphalted areas (streets, roads, courtyards next to residential buildings). The number of observation sites in individual locations ranged from 6 to 19 (a total of 103 sites). Series of measurements at individual sites were launched in the period 1998–2001 and completed in 2009–2012. On average, the duration of the series was 11.1 years. The measurements were made in the spring-autumn period annually (in some years at some sites two to three times a year) using a portable gamma-ray spectrometer-dosimeter. In the initial period of the study (1998–2001), the values of the absorbed dose rate in air from 137Cs were in the range from 40 to 2020 nGy/h. The maximum values were recorded in virgin meadows and forests, and the minimum ones were observed inside houses and over asphalted surfaces. By the end of our series of observations (2009–2012), the dose rate decreased at all sites, by an average of 33% (range 6–64%). The values of the ecological period of half-reduction of the dose rate, calculated for individual sites, ranged from 14 to 320 years and averaged 34 years (virgin soils located outside settlements), 30 years (virgin soils located inside settlements), 37 years (forests), 93 years (arable fields), 99 years (kitchen gardens), 33 years (other earth surfaces), 45 years (wooden houses), 60 years (asphalted areas). The deduced values of the rate of decrease of the dose rate of gamma radiation in the air in the surveyed locations were used to estimate the ecological period of the half-reduction of the effective external dose for rural population living in wooden houses. On average, this period was equal to 50 years. Given the radioactive decay of 137Cs, we can expect that the external dose from Chernobyl 137Cs to the rural population will decrease by approximately 4% per year. Our estimate of the rate of decrease of the external effective dose from 137Cs in the remote period after the Chernobyl accident is in agreement with the estimates that were previously given by other authors for the slow component of decreasing external doses from 137Cs to adults living in rural settlements of the Bryansk region.