The aim of the study. The development of decision-making algorithm for decisions on the social and medical protection of people in emergency situations based on risk analysis. Material and methods. The problems and conceptual provisions of risk assessment and decision-making, based on its results, are described concerning the social and medical protection of personnel of hazardous industries and the population in the event of an emergency situation (ES) in which the level of exposure to hazardous factors may exceed the established safety standards. The object of risk assessment and analysis are stochastic (probabilistic) effects of exposure to ES hazard factors. Their main features, which create complex problems in risk assessment and making decisions on protective measures, is the non-specific effects of the hazardous factors’ impact on human health and their possible latency. Results. The first step before decisions on the protective measures should be to identify a high-risk group among people affected by ES, based on the risk assessment. Three variants of decision-making for the high-risk group are considered: 1) financial compensation for risk, 2) medical measures for protecting health and 3) compensation for the realized damage to health. The requirements of the risk assessment methodology are formulated. Discussion. It is shown that the first option can not provide optimal and justified protection of the health and well-being of people in ES. Decisions on this protection are proposed to be based on a combination of options 2) and 3). The choice of the optimal combination depends on the specific situation and development of emergencies, on the success of implementing engineering and organizational protective measures aimed at preventing "doses" of exposure to people of hazardous factors of the emergency above the established safety limits and on the effectiveness and timeliness of medical protection. Conclusion. The choice of the option of making an effective decision on social and medical protection should be based on the detailed risk assessment from the exposure to hazardous factors, including risk assessment in economic indicators.

The aim of the study. An analysis of the problems of the development of the dose-effect relationship (DER) in the assessment of the risk under exposure to ionizing radiation (IR) and harmful chemicals (HC) on human health and proposals for improving them. Material and methods. Problems of the development and application of the methodology for assessing the risk of exposure to IR and HC are in the area of delivering DER based on the results of biological experiments and epidemiological studies (ES). These problems are associated with such properties of the effects of exposure to IR and HCh as nonspecificity and latency, low statistical power, fragmentation of the actual information available on the studied effects, possible dependence on the level of the associated spontaneous morbidity or mortality rate. A number of DER models have been developed by national and international organizations. However, between these models, there are significant differences in the choice both of model parameters and the ratio between the multiplicative and additive dependencies on spontaneous effects. The relevance of improving DER models suitable for reliable predictive risk assessments of exposure to IR and HC remains. Results. In modern DER models, the ratio between the multiplicative and additive dependencies on spontaneous effects was chosen by an expert way on the basis of the available results of biological experiments and ESs without sufficient rigorous justification. This was reflected in the different choice of this ratio by different developers. For a more reasonable choice of the ratio, it is proposed to consider two possibilities: 1) implementing additional targeted biological research on the molecular-cellular and organismic levels; 2) a joint analysis of the results of two independent ESs on different cohorts affected by exposure to IR or HC. For IR there is a real opportunity to solve the problem according to the second option. A specific possible method of action in the second direction and an algorithm for its implementation are proposed. Conclusion. Current models of DER for IR and HC require further development, in particular, in terms of the relationship between multiplicative and additive dependencies in DER. A method of justifying the choice of this ratio is proposed and an algorithm for its implementation for IR is described.

There are proposed conceptual positions and levels of decision-making on provision of the safety, social and medical protection of the human on the base of the assessment, analysis and risk management in different areas of human activity in normal and emergency conditions under the exposure to man-made and some natural hazard sources. At the base of developed applications there is a unified approach to the development and use of modern risk assessment methodology: the elaboration of a common method of the risk assessment and, basing on it, specific and simplified methods for concrete sources of hazard impact. This structure of methodological bases of risk assessment, in its full development makes it more transparent and comparable as well specific methods, as the support of decision-making on protective and other measures from different sources of danger. There were formulated proposals for universal safety standards (SSs) and other levels of decision-making on safety, social and medical protection of the population and staff of hazardous industries, including acceptable levels of risk. For the establishment of SSs and other decision-making levels, a special risk index is used: the relative damage (ratio of years of life lost to a year of stay-at-risk). This index is most appropriate for evaluation, comparison and management of risk, especially in conditions of two or more acting danger sources. On the base of universal SSs there are developed branch main SSs for certain isolated sources of danger. They are expressed in those indices (specific risk indices or impact indices in their different definitions), which by now are widely used in the practice or will be chosen for practical use in the future. In the ensuring human safety in normal conditions, the main use of the risk assessment is the development and support of SSs and other levels of decision-making. In emergencies the specific risk assessment besides to the establishment the decision-making levels is essentially needed to make justified optimal decisions on the measures of social and medical protection of the population and professionals.

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A study to assess the concentrations ratio of silver nanoparticles (Ag-NPs) in the blood and brain of the male Wistar rats using nuclear physical methods has been carried out. The Ag-NPs suspension including quasi-spherical Ag-NPs was administrated intravenously (in the tail vein for Ag-NPs of 9+2 nm and 94+10 nm), and for Ag-NPs of 94 nm diameter it was also administrated orally and intratracheally. The organ recovery was made in 24 h following the administration (for three types of administration) and one more time in 120 h in case of intravenous administration. Radioactive label in the nuclei of silver was created by irradiation of Ag-NPs suspensions in a flow of reactor thermal neutrons, and its share was 5.6 ∙ 10-7 of the total number of silver atoms. This fact could not affect the overall physical and chemical properties of radiolabeled Ag-NPs. We measured the activity of the 110mAg isotope-label in samples of blood and brain of rats, while the activity of 59Fe isotope was measured after the exposure to samples of these organs.Given the fact that iron is contained mainly in the hemoglobin of blood, on the basis of the measurement of 59Fe activity being the induced by neutron flux, we derived an evaluation of the residual mass of blood in brain capillaries using a standard procedure to prepare the samples. This determination is 0.058±0.010 g, and on average this is about 0 37±0.09% of the total mass of blood in rats. The estimated ratio of the Ag-NPs concentration in brain samples of rats (minus the Ag-NPs number in residual blood capillaries) to their peripheral blood concentration for 9 nm Ag-NPs is 0.16±0.04 and 0.31±0.07, and for 94 nm Ag-NPs - 0.20±0.05 and 0.29±0.07 for times in 24 and 120 hours after intravenous administration, respectively. For Ag-NPs of 9 nm and 94 nm diameter we revealed no significant effect of the Ag-NPs size on the value of this ratio. The same ratio for Ag-NPs of 94 nm diameter in 24 h after the oral and intratracheal administration is 0.29+0.09 and 0.41+0.12, respectively.