Vol 65, No 4-5 (2025)

The effects of radiation exposure of parents to the health of their offspring are an issue of discussion in radiation epidemiology. Despite various experimental and molecular and genetic research work indicating radiogenic effects in offspring the results of epidemiological assessment are quite controversial. Here is the review of epidemiological studies of the effects of preconception (prior to conception) exposure to the offspring of the first and next generations that were published in open access. Various cohorts of exposed individuals were observed: population of the areas with high natural radiation background; atomic bomb survivors in Japan; people who had suffered from nuclear weapon tests and radiation accidents; patients exposed to therapeutical and diagnostic radiation; workers who are in contact with ionizing radiation sources at their workplaces. Assessments of multivarious clinical implications among the offspring of exposed parents were cited: congenital malformations, immature deaths, alterations of height and weight parameters, irregularities of sex ratio, of cancer incidence rates, of immunological shifts, of somatic pathology, etc. It was noted that the presented cohorts are not comparable in terms of duration and rate of radiation exposure of the parents. No direct relation between unfavorable outcomes among the offspring and preconception dose loads of the parents was stated. The focus is made on shortcomings and difficulties of epidemiological studies including data collection via questionnaires, a lack of proper verification of medical outcomes in offspring, low statistical power, uncertainties of individual accumulated preconception doses, underestimation of non-radiation factors, short periods of follow up. In was finally demonstrated that the effects of preconception exposure to the health of the offspring are still a task to be solved. Public concern about late effects of radiation exposure in preconception period still remains high. Quantitative assessment of health risks among the offspring as a result of preconception ionizing radiation exposure is a priority research trend. Feasibility of epidemiological analysis based on the cohort of the offspring of Mayak Production Association — of the first nuclear facility in Russia — was described.

A methodology for establishing radiation causality of pathologies in chronic exposure to low-LET radiation in significant doses (0.4–1.0 Gy and higher) is proposed. It is relevant for accidents and extreme incidents of unintentional and intentional (nuclear and radiological terrorism). The use of risk assessments for nuclear workers (NW), for whom individual dosimetry is available, for modeling such effects seems to be the most correct approach. Based on the maintained and registered database on effects in NW, a complete sample of studies was formed that would have mortality risk assessments (Standardized Mortality Ratio; Relative Risk) from various pathologies for NW irradiated at doses from 0.4 Gy to 1.0 Gy and higher (systematic review). Mortality risks were assessed binary — “yes” (i.e. >1.0) or “not” (up to 1.0 inclusive). The percentage of risk detection was calculated for the samples for various pathologies. When a positive risk was found in >50% of studies, the causality of the pathology was considered to be attributable to radiation, similar to the Daubert Ruling in US courts. Using this method, attribution gradations of non-cancerous diseases and various types of cancer were established. It was found that these gradations, except for those identified for the most radiation-induced pathologies (leukemia and circulatory diseases), do not coincide with the table data for the Japanese cohort of victims of the atomic bombings (the LSS cohort). The proposed gradation for the consequences of chronic exposure on the population, professional and special contingents in the case of emergency, extreme or terrorist irradiation is more adequate due to a number of factors (chronic, not acute exposure, as in LSS, a more homogeneous contingent, the presence of individual dosimetry, etc.). The calculated standard “probabilities of radiation-induced diseases”, obtained on the model of NW effects, can serve as additional benchmarks for Interdepartmental Expert Councils to establish a causal relationship between developed pathologies and the radiation factor in the personnel of enterprises subordinate to the Federal Medical and Biological Agency of Russia and other departments. The absence of radiation attribution for a number of cancers and non-cancerous pathologies, even in relation to such irradiated groups of NW, will allow making a similar conclusion, but with even greater confidence, for significantly less irradiated professional groups within the Federal Medical and Biological Agency of Russia and the Rosatom system. And in the case of accidents and terrorist attacks, the developed methodology will provide reference information for subsequent assessment of the radiation-induced effects in victims.

2-Ethyl-6-methyl-3-hydroxypyridine succinate (EMHPS), the original domestic drug Mexidol, combines anti-hypoxic and antioxidant properties and is actively used in clinical practice in the treatment of various pathologies associated with oxidative stress. Today, the range of its applications is rapidly expanding. The therapeutic effect of EMHPS is complex and is implemented in several ways. The review examines the mechanisms of action of EMHPS as a potential radiomodulator, and presents the results of its successful use in experimental radiation sickness and radiation/chemoradiation therapy of malignant tumors.

Freshwater bodies with high radioactivity are often contaminated with chemicals, including heavy metals. Of particular interest is cadmium, which is toxic to living organisms. The article considers the effects on different levels of biological organization in duckweed Lemna minor L. when exposed to acute γ-radiation and cadmium ions (Cd²⁺). The plants were irradiated at doses of 11 and 63 Gy, and then cultured for 7 days on a medium with 0.315 and 12.6 µmol/L Cd²⁺, which corresponded to the minimum effective and half-maximum (50%) intensities of the impact of these factors on the specific growth rate of the laboratory duckweed culture. The effect of interaction of factors was calculated using median effect analysis. The growth rate under joint action was lower in most cases compared to the separate action of only radiation or Cd²⁺. Growth rate inhibition at 63 Gy and 12.6 µmol/L Cd²⁺ increased to 65%. Analysis of the effects at the population level showed that at low radiation doses the factors interacted as antagonists, and at high doses as synergists. Under the influence of stressors the average size of fronds (green plates) decreased: by 35% at 12.6 µmol/L Cd²⁺, by 15% under γ-radiation (63 Gy), and by 41% under combined action compared to untreated plants. Under combined action of the factors the degree of damage to the frond surface in the form of chlorosis and/or necrosis increased, including up to 100% at 63 Gy and 12.6 µmol/L Cd²⁺. The degree of frond damage is associated with a decrease in chlorophyll a content (r = −0.76, p < 0.05) and an increase in malondialdehyde concentration (r = 0.91, p < 0.05). At 12.6 µmol/L Cd²⁺ in the medium, the chlorophyll content decreased by half compared to unexposed plants. In contrast, high doses of radiation contributed to an increase in the content of chlorophylls and carotenoids (p < 0.05). After 11 and 63 Gy, Cd²⁺ accumulation in the tissues of irradiated plants increased by 1.8 and 3.2 times compared to unexposed plants at 0.315 µmol/L Cd²⁺ in the medium (p < 0.05). This study confirmed the importance of risk assessment for radioactive contamination of water bodies, taking into account the toxicity of associated stressors.

Data on contents of ¹³⁷Cs, ⁹⁰Sr, and ³H in surface water and their accumulation in bottom sediments and floodplain soils of the Pyshma River at a distance of up to 50 km from the Beloyarsk Reservoir on the 2024 are presented. An assessment of the annual discharges of artificial radioisotopes in the surveyed river section, including discharges from the Beloyarsk Reservoir, was executed. Using the annual drains balance calculation method, the main source of technogenic radionuclides entering the Pyshma River was identified as the Olkhovka swamp-river system, where average annual discharge of ¹³⁷Cs and ⁹⁰Sr from the Olkhovka River is 1.6 times higher than from the Beloyarsk Reservoir. The integrated stocks of ¹³⁷Cs in the bottom sediments and floodplain soils of the Pyshma River amounted to 8.63 GBq, which is 8.4 times greater than the stocks of ⁹⁰Sr and 4.3 times higher than the annual ¹³⁷Cs discharge at the endpoint of the surveyed river section. It was shown that ¹³⁷Cs entering the Pyshma River is sorbed by components of the river ecosystem, maintaining its reserves at a stable level. The annual ⁹⁰Sr discharge through the final river cross-section of the surveyed segment of the Pyshma River is 7.1 times greater than its integral reserves in floodplain soils and bottom sediments; therefore, this radionuclide, which has a higher migration capacity, is carried away with the water flow beyond the surveyed section of the river. It was shown that the uncontrolled removal of technogenic radionuclides from the Olkhovskoye swamp into the open hydrographic network creates a potential threat of radiation safety for downstream sections of the Pyshma river, which is part of the Ob-Irtysh river system, determines the need for systematic radioecological monitoring of aquatic ecosystems affected by the Beloyarsk NPP.

The analysis of changes in the ¹³⁷Cs aggregated transfer factors (T_ag) to the milk of farm animals in the southwestern districts of Bryansk region from 1986 to 2014 is presented. Several time intervals with different patterns of T_ag half-lives were identified. The first half-life, calculated for 1987—1992, was 0.76 years. Since 1996, the reduction of ¹³⁷Cs transfer factors to milk slowed significantly and became inhomogeneous. Differences in the dynamics of ¹³⁷Cs aggregated transfer factors to milk were noted in zones with different ¹³⁷Cs deposition densities.

A critical analysis of information on the parameters of thorium isotope transfer to animal organs and tissues is presented. Isotopic differences between ²²⁸Th, ²³⁰Th and ²³²Th are noted. It is shown that the greatest amounts of thorium are accumulated in the bone tissue of animals, and the minimum amount in muscles. It is noted that contamination of animal diet with soil is an important pathway of ²³²Th intake into animal organism. For wild animals, the highest transfer coefficients were observed for reptiles, and the lowest for mammals.