As the result of the Chernobyl NPP accident more than 200 thousand square kilometers of the European territories were contaminated by Cs-137 in the amount of above 37 kBq/m2 (1 Ci/km2 ). Belorussia, Russia and Ukraine amount up to 70% of this entire affected area. More than 600 000 people were engaged in the accidental cleanup operations, 340000 were evacuated or relocated within 1986-1991. The early stage evacuation efficacy is confirmed by the absence of acute radiation syndrome among the population and by the prevented collective dose which amounts to no less than 10 000 man/Sv. The effective measure to reduce the internal radiation dose to the population at the early accidental stage was introduction of maximum tentative permissive levels of radionuclide content in the foodstuffs.Among the identified post -accident medical consequences of the Chernobyl is the radiation syndrome found in 134 emergency cleanup workers within the first 24 hours of the accident’s development. Out of that number, 28 people died within the first four months, 19 people died before 2006. The accident’s liquidators developed radiation -induced leukemia ( the attributive risk value is 45-60% ). People exposed to high radiation doses display the statistically significant 18% morbidity increase of all types of solid cancers at the doses above 150 mSv. There is the statistically significant information indicating the increased amount of thyroid cancer morbidity among those who were just children and teenagers at the time of the accident. The adverse psychological consequences are accounted for not just the fear of overexposure but also for the disturbance of the habitual lifestyle especially mindful of the forced relocation.The longterm protection measures, radionuclide decay and selfcleaning of the contaminated areas resulted in the drastic reduction of the population dose in the radioactively contaminated territories. In 2015, only in some settlements of the Briansk Region’s the mean annual effective dose to the population exceeds 1 mSv. Presently the major goal is to transfer to normal human life with the change of the legal status of radioactively contaminated settlements in which the radiation situation is back to normal.The article provides the comparative data on the Chernobyl and the Fukushima - 1 accidental consequences and emphasizes the necessity of retaining the Chernobyl experience because the rapid advancement of the atomic energy around the world makes the mitigation of the accident’s consequences a truly international mission.

The state policy of the Russian Federation to ensure population, living in the contaminated areas, life safety is implemented by means of federal programs.12 programs for overcoming the Chernobyl accident consequences, children’s population protection and housing provision for the Chernobyl accident liquidators are adopted and realized during this time. Total financing amount from the federal budget is more than 9,2 billion rubles. The main efforts are directed to create necessary infrastructure in settlements, development and deployment rehabilitation measures for agricultural lands and forests, creation of radiation situation monitoring systems, increase housekeeping safety culture in the contaminated territories, informational support and social and psychological rehabilitation of the population. Within the state programs are developing complex systems of a radiation situation monitoring in 12 subjects of the Russian Federation. Experts training for the outreach work with population, concerning radiation safety, increasing population knowledge level about radiation in a format of seminars, conferences, with use of online technologies is provided. The project on creation the uniform interdepartmental information system on overcoming radiation accidents aftermath, integrating the operating information systems of The Ministry of the Russian Federation for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters, Federal Service for Hydrometeorology and Environmental Monitoring, the Russian Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing and the Russian Academy of Sciences is realized.However, the problem of overcoming the radiation accidents aftermath remains relevant up to date.In 14 subjects of the Russian Federation there are territories contaminated by radioactive materials as a result of the Chernobyl accident where more than 1,5 million people live.

The Belarus National Commission on Radiation Protection was established in 1991, based on the former Byelorussian Soviet Socialist Republic Supreme Council Resolution. The Commission works out recommendations on the radiation protection to submit to the state authorities, state institutions under the Republic of Belarus Government and state research institutions, reviews and assesses scientific data in the field of radiation protection and makes suggestions in regards of the implementation of the achieved developments. The Commission engages leading scientists and practitioners from Belarus, involved in the provision of the radiation protection and safety in the state. The methodological cornerstone for the Commission activities was chosen to be the committment to the worldwide accepted approach of the nature and magnitude of the undertaken protective measures justification in the field of radiation safety. The Commission adheres the ALARA optimization criteria as the core of the aforementioned approach. The Commission has also submited to the Government a number of developments which were crucial in the highest level managerial decisions elaboration. The latter impacted directly the state tactics and strategy in the environmental, health and social consequences of the Chernobyl disaster minimization. Following the recommendations of the international institutions (ICRP, IAEA, UNSCEAR, FAO/WHO), developments of the colleagues in the Russian Federation, Ukraine and the local regional experience, the Commission proceeds with the expert observation of the ongoing protective measures to reduce the radiation impact and population exposure resulted from the Chernobyl accident, is actively occupied in the radiation safety ensuring at the Belarussian nuclear power plant being under construction, much contributes to elaboration of the new version of the state Law “On Radiation Protection of Population” and other regulatory documents.

In an existing exposure situation (in a remote period after the Chernobyl accident) there is a need of the transition from "radioactive area zoning" to "the settlements classification by average annual effective doses to the critical group of persons among the settlement's residents", to ensure the appropriate radiation level and social protection of the settlement's residents, located on the contaminated territory.The comparative allocation analysis of the average annual external and internal effective doses, the average annual effective cumulative doses to residents of settlements, related to the relevant areas (the Council of Ministers of Belarus latest decision, the proposed dose range according to the Catalogue of average annual effective doses of residents of settlements radiation Republic of Belarus) confirmed the validity of the transition from "radioactive zoning area" to "the classification of settlements by average annual effective dose."In accordance with the radiation protection principles, it seems reasonable to classify the settlements located on the contaminated territory at the average annual effective dose as follows: < 0.1 mSv / year (not required to carry out radiation protection measures in the agricultural sector);  0.1-1 mSv / year (periodic radiation monitoring should be carried out);  1 mSv / year (it is necessary to apply a complex of protective measures).

The article describes radiation conditions in the Kaluga region 30 years after the Chernobyl NPP accident. The Chernobyl NPP accident caused radioactive contamination of nine Kaluga region territories: Duminichsky, Zhizdrinsky, Kuibyshevsky, Kirovsky, Kozelsky, Ludinovsky, Meshchovsky, Ulyanovsky and Hvastovichsky districts. Radioactive fallout was the strongest in three southern districts: Zhizdrinsky, Ulyanovsky and Hvastovichsky, over there cesium-137 contamination density is from 1 to 15Ci/km. According to the Russian Federation Government Order in 2015 there are 300 settlements (S) in the radioactive contamination zone, including 14 settlements with caesium-137 soil contamination density from 5 to 15 Ci/ km2 and 286 settlements with the contamination density ranging from 1 to 5 Ci/km2. In the first years after the Chernobyl NPP accident in Kaluga region territories, contaminated with caesium-137, there were introduced restrictive land usage, were carried out agrochemical activities (ploughing, mineral fertilizer dressing), there was toughened laboratory radiation control over the main doze-forming foodstuff. All these measures facilitated considerable decrease of caesium-137 content in local agricultural produce. Proceeding from the achieved result, in 2002 there took place the transition to more tough requirements SanPiN 2.3.2.1078-01. Analysis of investigated samples from Zhizdrinsky, Ulyanovsky and Hvastovichsky districts demonstrated that since 2005 meat samples didn’t exceed the standard values, same for milk samples since 2007. Till the present time, the use of wild-growing mushrooms, berries and wild animals meat involves radiation issues. It was demonstrated that average specific activity of caesium-137 in milk samples keeps decreasing year after year. Long after the Chernobyl NPP accident, the main products forming internal irradiation doses in population are the wild-growing mushrooms and berries. Population average annual effective doses, caused90by Chernobyl fallouts, do not exceed 1 mSv/year. In 2014 AAEDmaximum calculated value for adultpopulation of 0,91 mSv was established in the following settlements:, Martynki village(Ulyanovsky district) and Lovatyanka village (Hvastovichsky district). The doses, accumulated in the period after the accident, are generally not high. According to calculations numerical value of forecasted accumulated doses varies from 0,23 to 21 mSv. Maximum calculated values of 21 mSv are established in Hvastovichsky district (Lovatyanka village) and Ulyanovsky district (Martynki village). Between 1986 and 2005, the effective irradiation doses did not exceed 29 mSv. Hence, in 70 years after the Chernobyl NPP accident standard value of 70 mSv will not be exceeded in the Kaluga region settlements. After 30 years, the main cause of population internal exposure is consumption of products from private subsidiary farms and especially of wild-growing products. There was conducted radiation monitoring of local agricultural foodstuff produce and of products from the forest. It demonstrated that caesium-137 average specific activity in samples of milk from private subsidiary farms in settlements of Zhizdrinsky, Ulyanovsky and Hvastovichsky districts decreased several-fold. It is between 20,0 Bq/l in 2007 and 1,7 Bq/l in 2015. In 2015, maximum levels of caesium-137 contamination in milk was 3,1% of the standard value, in potatoes - 4,7%, in meat - 4,4%.Average specific activity of caesium-137 in forest mushrooms samples from Zhizdrinsky, Ulyanovsky and Hvastovichsky districts doesn’t decline. Peaks of average caesium-137 activity were observed in 2012, 2013 and 2014; they depend on mushrooms abundance, species, dry summer weather and locations of sampling in the forest. In 2015 in three southern districts, the maximum content of caesium-137 in mushrooms exceeded the permissible level (500 Bq/kg) 4,5-fold; about 2% of the samples do not correspond to it. The maximum contamination of berries with caesium-137 also exceeds the permissible level (160 Bq/kg) nearly 5-fold, and about 43% of samples don’t correspond to it. Obtained results have demonstrated that long after the Chernobyl NPP accident (30 years) the main part of population internal exposure is caused by consumption of wild- growing mushrooms and berries. In the recent years, milk consumption does not play a considerable role in forming of internal dose any more. Conclusion: in 30 years since Chernobyl NPP accident in the Kaluga region radiation and environment conditions have considerably improved on the territories with radionuclides contamination. However, problems remain. The major task for mitigation of the Chernobyl NPP accident consequences is comprehensive radiation, social and economic rehabilitation of the contaminated territories.

Over 50% of Tula Region areas were contaminated after the Chernobyl NPP accident. The article provides the thirty years’ results of radiation hygienic monitoring of the Chernobyl accidental fallout - affected areas in Tula Region. The radiation situation is assessed at the initial accidental period and at the current stage. The initial levels of gamma - radiation dose intensity (up to 35 mcSv/hr ) are identified for the period of the “iodine” hazard along with the tabular data on the dose intensity relative stabilization by the beginning of August 1986 due to iodine-131 decay. The information is presented regarding iodine-131 tentative maximum permissible level exceedance in the dairy products of the two most contaminated regional areas - Plavskoye and Arsenievskoye. The article also provides the laboratory data on the total beta - activity in the foodstuffs in 1986-1987 and cesium-137 maximum permissible level exceedence in 1986. The radionuclide maximum permissible level exceedances in foodstuffs were registered only in 1986 due to the plants surface contamination whereas in the forest mushrooms those exceedances were repeatedly found until 2004. The black earths and grey forest soils had a benign impact upon the intensity of the radionuclide transfer into plants which resulted in the formation of internal radiation doses.At the current stage, the content of cesium-137 and strontium- 90 in the foodstuffs can only be quantified by a radiochemical method. The table covers all the districts within the boundaries of radiation contaminated zones. The radiochemical studies indicate the main dose - forming products. The article contains the table of internal and external radiation doses of the population in Plavsk town over 1986-1990 and displays the factors impacting population’s internal and external exposure. The Chernobyl - affected exposure dose of the population is mostly attributed to the external radiation and, for over twenty years, it does not exceed 1 mSv/ year. The annual effective dose of the population from 96,2% of the settlements is below 0,3 mSv/year.

Research objective is retrospective analysis of radiation conditions in the Oryol region during 1986- 2015 and assessment of efficacy of the carried out sanitary and preventive activities for population protection against radiation contamination caused by the Chernobyl NPP accident.Article materials were own memoirs of events participants, analysis of federal state statistic surveillance forms 3-DOZ across the Oryol region, f-35 “Data on patients with malignant neoplasms, f-12 “Report on MPI activities”. Risk assessment of oncological diseases occurrence is carried out on the basis of AAED for 1986- 2014 using the method of population exposure risk assessment due to long uniform man-made irradiation in small doses. Results of medical and sociological research of genetic, environmental, professional and lifestyle factors were obtained using the method of cancer patients’ anonymous survey. Data on "risk" factors were obtained from 467 patients hospitalized at the Budgetary Health Care Institution of the Oryol region “Oryol oncology clinic”; a specially developed questionnaire with 60 questions was filled out.The article employs the method of retrospective analysis of laboratory and tool research and calculation of dose loads on the Oryol region population, executed throughout the whole period after the accident.This article provides results of the carried out laboratory research of foodstuff, environment objects describing the radiation conditions in the Oryol region since the first days after the Chernobyl NPP accident in 1986 till 2015.We presented a number of activities aimed at liquidation of man-caused radiation accident consequences which were developed and executed by the experts of the Oryol region sanitary and epidemiology service in 1986-2015. On the basis of the above-stated one may draw the conclusions listed below. Due to interdepartmental interaction and active work of executive authorities in the Oryol region, the population of the territories impacted by radioactive contamination is provided with conditions in compliance with radiation safety requirements and hygienic specifications.Since January 1987 according to radiation and hygienic monitoring in the Oryol region, the local foodstuff did not exceed the hygienic specifications on radiation. In the territories included in the zone of radioactive contamination, the economic activities may be carried out without special protective measures for decrease of caesium-137 and strontium-90 content in produce, there are no restrictions on picking of wild-growing berries, herbs and mushrooms.Being direct participants of development and carrying out of activities for the region protection in case of emergency situation at the radiation hazardous site, we believe that the data presented in this article may be useful both for experts and general population.

The goal. The analyses of radiation hygienic monitoring conducted in Tula region territories affected by the Chernobyl NPP accident regarding cesium-137 and strontium- 90 in the local foodstuffs and the analyses of populational annual effective dose. The materials and methods. The survey was conducted in Tula Region since 1997 to 2015. Over that period, more than fifty thousand samples of the main foodstuffs from the post-Chernobyl contaminated area were analyzed. Simultaneously with that, the external gamma - radiation dose rate was measured in the fixed control points. The dynamics of cesium -137 and strontium-90 content in foodstuffs were assessed along with the maximum values of the mean annual effective doses to the population and the contribution of the collective dose from medical exposures into the structure of the annual effective collective dose to the population. The results. The amount of cesium-137 and strontium -90 in the local foodstuffs was identified. The external gamma- radiation dose rate values were found to be stable and not exceeding the natural fluctuations range typical for the middle latitudes of Russia’s European territory. The maximum mean annual effective dose to the population reflects the stable radiation situation and does not exceed the permissible value of 1 mSv. The contribution of the collective dose from medical exposures of the population has been continuously reducing as well as the average individual dose to the population per one medical treatment under the annual increase of the medical treatments quantities. The conclusion. There is no exceedance of the admissible levels of cesium-137 and strontium- 90 content in the local foodstuffs. The mean annual effective dose to the population has decreased which makes it possible to transfer the settlements affected by the Chernobyl NPP accident to normal life style. This is covered by the draft concept of the settlements’ transfer to normal life style.