Radionuclides (40K, 232Th, 226Ra, 137Cs, and 90Sr) in Agroecosystems of the Central Chernozem Region

Studies were conducted in 2023–2024 at reference sites of Belgorod oblast. The study procedure is conventional in the agrochemical service. The purpose of this work is to study the specific activity of natural and artificial radionuclides in the soils and the plants of certain agroecosystems. These studies have shown that the average specific activity of 40K does not vary significantly in the leached (539 Bq/kg), typical (544 Bq/kg), and ordinary (573 Bq/kg) arable chernozems, while in the residual carbonate chernozems, this parameter (207 Bq/kg) is 2.60–2.77 times lower. The average specific activity of 232Th in the leached (39.2 Bq/kg), typical (42.9 Bq/kg), and ordinary (46.7 Bq/kg) chernozems is 1.97–2.35 times higher than in the residual carbonate (19.9 Bq/kg) chernozems. The average specific activity of 226Ra in the soils studied do not differ significantly, staying within 17.3–18.9 Bq/kg. In the soils of the western and eastern areas of the region, the specific activity of 137Cs ranges within 5.9–19.6 and 16.3–87.2 Bq/kg, respectively. The specific activity of 90Sr in the soils of the western regions is below 3, whereas for the eastern, it is below 5 Bq/kg. In the plant products studied, the average specific activity of 40K varies within 111–597 Bq/kg, while those of 232Th and 226Ra do not exceed 6 and 8 Bq/kg, respectively. The specific activity of 137Cs is less than 3, and that of 90Sr is 2 Bq/kg, which is significantly lower than the established maximum levels for this parameter.