The article presents preliminary assessment of the accident scale, level of its radiation effect on the population and response of national authorities of various countries for the population radiation protection provisions. High levels of the environmental radioactive contamination demanded the application of complex measures for the radiation protection of the population from adjacent territories of Japan. Radionuclides from the region of damaged NPP can get to the other countries by means of the long-distant air and sea water mass transfer. Specific activity of cesium radionuclides in the sea biota can reach the level recommended by the Codex Alimentarius Commission as the safe level for the international trade or exceed it. Significant radioactive contamination of the territories of other countries resulting from the «Fukushima-I» NPP accident did not occur. Many world countries applied measures of the Japanese food products import control on the base of the radiation monitoring data. These prohibitions are consequently remitted following the radiation situation improvement.

Basic measures of the Rospotrebnadzor emergency response during the early stage of the «Fukushima-I» NPP radiation accident are being analyzed in the article. Radiation monitoring of the environmental objects of the territories of the Russian Federation Far East Federal District, radiation control of arriving from Japan vehicles, freights and passengers as well as imported from Japan food products were promptly organized. This allowed to get reliable evaluations of the levels of radioactive contamination at the Russian Federation territory and population exposure doses due to the «Fukushima-I» NPP accident, timely exclude the possibility of import to the Russian territory for the freights, vehicles, food products having contamination exceeding established in the Russian Federation standards.

An article is devoted to the analysis of the radiation situation in the dynamics during the years since the accident at the Chernobyl nuclear power plant in 1986. Data on the scope of activities fulfilled for the assessment of the territories radioactive contamination levels and foodstuffs contamination levels, on the values of the exposure doses for the population living on the contaminated territories, on the medical and socio-psychological consequences of the Chernobyl accident is presented. Basic norms and principles, used during the protective measures development and introduction, are considered, their effectiveness is demonstrated. Mistakes emerged during protective measures implementation are analyzed, the prognosis of the population exposure dose values for the 70-year period since the accident and main directions of activities for the contaminated territories remediation and normal life conditions restoration for the population at these territories are presented.

Radiological consequences of the accident at the Chernobyl NPP were recently revisited by the UN Chernobyl Forum (2003-2005) and UNSCEAR (2005-2008). For the first time environmental impacts were considered in detail, including radioactive contamination of terrestrial and aquatic environments, application and effectiveness of countermeasures and effects on biota. Updated dosimetric data were presented for more than half a million of emergency and recovery operation workers, about 100 million inhabitants of the three most affected countries, Belarus, the Russian Federation and Ukraine, and for 500 million inhabitants of other European countries. Several hundred of the emergency workers received high radiation doses; of whom 28 persons died in 1986 due to acute radiation sickness. Children at the time of the accident, who drank milk with high levels of radioactive iodine, received high doses to the thyroid. Since early 1990s there was the dramatic increase in thyroid cancer incidence among them. Also in 1990s there was some increase of leukaemia in most exposed workers. The UN Chernobyl Forum concluded that severe social and economic depression of the affected regions and associated psychological problems of the general public and the workers had become the most significant problem. The vast majority of the population need not live in fear of serious health consequences from the Chernobyl accident.

Morbidity and mortality among emergency workers of the Chernobyl accident for the follow- up period of 199Morbidity and mortality among the emergency workers of the Chernobyl accident for the follow-up period of 1992-2008 is analyzed in the article. The cohort consists of 47141 emergency workers of 1986-1987. Radiation risks for cancer morbidity (ERR/Gy is 0.76; 95% CI: 0.19; 1.42, p-value=0008) and cancer mortality (ERR/Gy is 0.95; 95% CI: 0.19; 1.89, p-value=0.01) are statistically significant. Radiation risk for vascular diseases is assessed as well.

Results of the poll on the lifestyle and nutrition of the population of the most contaminated areas of the Bryansk and Tula regions during the initial period after the accident at the Chernobyl nuclear power plant are presented in the article. The poll was held at the beginning of 1987. Mean values of numeric factors were derived form the results of processing of questionnaires received from 8500 persons, namely: value of milk daily consumption depending on the age and place of residence, the date of the dairy cattle grazing starting, time of milk consumption termination in May 1986, time spent by the person outdoors and in the dwelling, data on the leaving of the contaminated territory. Obtained information is used for the clarification of models for the internal and external exposure dose calculation and for personalization of the dose estimations for the individual inhabitants.

Regulation of decision making on protection of the public from radiation exposure caused by the Chernobyl accident is retrospectively reviewed. Decisions on prime countermeasures such as evacuation of population from 30 km zone around the Chernobyl nuclear power plant were taken on the ground of a priori developed criteria. The next years, elaboration of a set of regulating documents was needed for implementation of countermeasures corresponding to real conditions of unprecedented scale and levels of radioactive contamination of large territory. Within several years the temporary permissible levels of radiation exposure and content of radionuclides in foodstuff were adopted for current operative decisions. The subsequent decisions made under a pressure of sociopolitical circumstances resulted in a compromise between radiation protection principles and inadequate public perception of radiological risk. Now a decision is needed to solve a problem of the return of radioactively contaminated territories to normal life. The analysis of experience gained in overcoming of consequences of the Chernobyl accident is of great importance for perfection of readiness for management of radiological emergencies.

Young people that were born and are living now on the radioactively contaminated territories assess the danger of radiation for the health at the same level as dangers of mostly harmful environmental factors. Besides, the clear downward trend of the level of mental and, especially, physical health was revealed among male young people living on the territories with the highest levels of radioactive contamination. Apart from that, deviations of integral indexes of the life quality for all polled groups living on radioactively contaminated and non-contaminated territories do not exceed 10% (assessment of the life quality according to the method SF-36) and one point (linear 10-points assessment scale).

The article presents two alternative points of view on the relationship of health malfunctions after the Chernobyl accident with radiation effect or with the factors of non-radiation nature (social, stress, nutrition peculiarities, etc.). An analysis of literature data and results of author’s own research of radiosensitive indicators of immunity condition, having essential value for the immediate and long term consequences of radiation effect was done. Possible correlation between health malfunctions of the population living in the regions, contaminated by the radionuclides, and combined effect of radiation and factors of non-radiation nature is shown.

The result of the carried investigation of participants of liquidation of Chernobyl accident consequences, suffering from organic disease of a brain of a vascular origin with mental infringements, and patients with the similar pathology, not exposed with radiating influence, revealed a number of the сlinico- psychopathological and paraclinical peculiarities testifying heavier current of disease among liquidators, forming a chronic ischemic condition of a brain, and the atrophy phenomena among mentioned group.

Dynamics of the cancer morbidity for the population during the period from 1980 to 1986 as well as during the period from 2004 to 2006 was investigated in 14 regions of the Russian Federation affected by the radioactive contamination due to the Chernobyl accident. Comparison of the indicators with the data from the Orenburg region was done. A moderate upward trend of the actual indicators was revealed as the result of their analysis. General morbidity for the urban population was higher than for the rural population.

Mathematic models based on the data from 80-ties were created for the calculation of expected values of morbidity indicators in 2004 to 2006. During the comparison of the actual and expected values it was revealed, that actual morbidity for the urban population was less than calculated value except for the Kaluga and Orenburg regions. As a rule, actual morbidity for the rural population exceeded calculated value.

Dynamics of the population cancer mortality for the period from 1980 to 1986 as well as for the period from 2004 to 2006 was investigated in 14 regions of the Russian Fed-eration affected by the radioactive contamination due to the Chernobyl accident. Comparison of the indicators with the relevant data from the Orenburg region (control) was done. Mathematic models based on the data from 80-ties were created for the calculation of hypothetic values of mortality indicators in 2004 to 2006. Comparison of actual and predicted values demonstrated that actual morbidity for the urban population was less than the calculated one. Comparison of actual and predicted values of the cancer mortality also demonstrated that for the majority of nozological forms the predicted levels were higher than the actual levels.

Investigation results of the contamination with ¹³⁷Cs and ⁹⁰Sr of the plants from natural ecosystems of four objects are being presented. 45 plant samples and 24 soil samples were analyzed. It was revealed that the permissible level for the ¹³⁷Cs content of 370 Bq/kg, is exceeded for 21 samples (46.7 %). Content of ⁹⁰Sr in plants varied from 3 Bq/kg to 544 Bq/kg. Most part of the radionuclides still remains in the upper soil horizons. Plant species specificity concerning the radionuclide accumulation depends on the composition of the natural ecosystem, type of soil, its agrochemical composition and humidity.

An article considers issues related to the radiological examination of the people arrived in Leningrad from the areas radioactively contaminated due to the Chernobyl nuclear power plant accident. It also describes the experience of creation and functioning of the specialized station for radiation control and sanitary treatment of people and their personal clothes. The article specifies basic requirements for such stations.

The article briefly presents the experience of the radiation-hygienic monitoring system creation in the territory contaminated with the radionuclides due to the Chernobyl accident and application of the radiation hygienic monitoring data for the assessment of protective measures efficiency. Radiation situation data for the territory of the Bryansk region after 25 years of Chernobyl accident and dynamics of the population average annual effective exposure dose are being presented.

The paper presents the results of radiation situation monitoring on the territory of the Orel region after the accident at the Chernobyl NPP. Actions of the sanitary epidemiological authority for the emergency response management, actions of the region administration for the population protection from the overexposure are analyzed. Data on morbidity of the liquidators of Chernobyl accident and region inhabitants, living on the contaminated territories, is presented.