The paper presents a review of the data on radioactivity releases to thePacific Oceanlevels after the Fukushima NPP accident. It is shown that the potential risk of of the seafood contamination with the long-living radionuclides 134Cs and 137Cs, which continue to be released to the Pacific Ocean up to the present time. Contribution of 90Sr to the total radioactive contamination does not exceed 3%. Review of the literature data on the modeling of radioactivity spot diffusion showed that due to the flows in the Pacific Ocean the radioactivity transfer toKamchatka Peninsula, the Kuril Islands, and the ingress into theOkhotskSeawas expected in 2014. It is expected a slight increase of the cesium concentration in water and sea biota in the area of Russia fishing zone FAO 61, but not higher than the concentrations in the Black Sea and Baltic Sea after the Chernobyl accident. Data on measurements of the pollution of fish caught in the Pacific Ocean,JapanandOkhotskSeasin 2011–2014 years during the sea expeditions organized by the Russian Geographical Society, yet showed that the total content of cesium isotopes in any fish sample have not eceeded the value of 0.7 Bq/kg. The prognose risk assessment carried out for the conservative scenario of water contamination in fishing zones ofRussiaand seafood consumption characteristic for the region showed that this risk is minimal according to the WHO scale and does not exceed the risk from fish caughed in Black Sea and Baltic Sea, contaminated after theChernobylaccident, consumption.

Objective: comparative evaluation of carcinogenic risk inMoscowfrom radon in indoor and atmospheric pollutants.

Materials and methods: the lung cancer incidence in Moscow; radiation-hygienic passport of the territory; .U.S. EPA estimated average age at all and radon induced deaths, years of life lost; Report of UNSCEAR 2006 and WHO handbook on indoor radon, 2009. Trend analysis of incidence; evaluation of the excess relative risk; assessment of ratio radon-induced population risk and published values оf total population carcinogenic risk from chemical carcinogens.

Results: it is shown that the 304 cases of lung cancer per year (1. 85 10^-3) on average from 2006 to 2011 (21280diseases for 70 years in addition to background level) induced by radon; the differences in average trends of all lungcancer incidence in the districts can exceed 25%.

Conclusion. The potential of risk reduction by measures of mitigation radon concentration exceeds 5 times the cost efficiency to reduce emissions from vehicles and can reduce cancer incidence, on average 236 cases per year; population risk 16520 cases over 70 years or save not less than 2832 person-years of life per year. The annual effect of reducing losses from not-survival of 12 years as a result of radon-induced lung cancer deaths exceeds 14160000 dollars. The evaluating of the carcinogenic risk from radon in accordance with the definition of population risk increases the predictive evaluation of the effectiveness of preventive measures more than twice.

The purpose of the work was to obtain data about the level of population radon exposure on the surveyed settlements.

Methods. Surveys were carried out by the integral track method with the use of the track chambers REI-4 from the kit TRACK-REI-1M. Were surveyed dwelling, schools, kindergartens and business premises. Duration of the each exposure was 2-4 months. The measured value was radon volume activity, then effective equilibrium radon concentration (EEC) was calculated using the values of the equilibrium coefficient F=0,5. Effective dose from radon was calculated using a dose coefficient 9•10^-6mSv/(hour•Bq/m³). Describe theorganizational aspects of the surveys are described.

Results. Survey of the premises to radon were conducted in the settlements of 26 administrative units for several seasons in 2008–2013. The surveyed settlements are cities with multi-storey or mixed buildings sites. The number of inspected premises in the settlement in one measurement period typically ranged from 100 to 200. Most premises were surveyed at least for two seasons (warm and cold). The total number of measurements is about 5300. The summarized results for all settlements were obtained: intervals and average values of the radon EEC, doses fromradon, the proportions of premises with EEC less than 100, 200 and 400 and more than 400 Bq/m³. The calculatedannual doses to the population from radon in a number of settlements are presented. Conclusion.Summarized information about the exposure of the population to radon are obtained. It is shown that «winter» radon EEC values not always exceeds summer values. For part of the settlements we can see even opposite picture. Criteria for assessing the relevance of the «radon situation» in the settlement are proposed. Based on the results of performed surveys the settlements ranked using this criterion.

A mathematical model for radiogenic increasing of mortality was proposed, taking into account spontaneous background damages of the genetic material, that always occur in cells due to the influence of non-radiation internal and environmental factors. The model is based on the representation of indistinguishability between radiogenic andspontaneous cancers and on the postulates of the Kellerer-Rossi dual action theory. It was proposed that duringformation of premalignant damages dual interactions occur both between primary radiation damages, and betweenradiation and spontaneous primary damages (hybrid interactions). The role of the latter is particularly important at low levels exposure that corresponds to a linear dependence of cancer incidence on dose. Their significance is indicated by the following factor: at the adopted value of the nominal (radiation) risk factor (0,05 Sv^-1) and cancer mortality share among the population (0,15–0,2), the contribution of non-radiative carcinogenic factors for the total life is equivalent to radiation dose of 3–4 Sv or radiation at a constant dose rate of 40–50 mSv / year.

The model assumes formation in DNA of both spaced apart (single) damages with high probability of recovery, and nearby (double) damages, which are more likely to interact, entering into the permanent state. Permanent damages being formed in certain portions of DNA can be inherited to daughter cells as premalignant defects. The relative role of spontaneous primary damages is greater the more single damages are formed as compared to double ones within the area of potential interaction.

It was shown within this model that the presence of background cancer mortality for initial and finite population in the used by ICRP expression for interpopulation risk transfer has logical and biophysical justifications. Accounting of spontaneous primary damages and hybrid interactions enhances the capabilities for development of radiation risk models.

The purpose of research was to assess the dynamics of the changes during the five-year period (from 2008 to 2013) of the radiation situation in the territory adjacent to the places of the peaceful nuclear explosions of the “Dnepr” series in the Murmansk region, the analysis of information environment of the subject in the Internet and the study of the population public opinion.

Gamma-radiation dose rate registered in the investigated territory in 2013 (140 – 180 nSv/h) corresponded to the natural radiation background, characteristic for the Khibiny. The average content of ¹³⁷Cs in soil is comparable to the level of the global fallout contamination. Levels of the artificial radionuclides concentration in the samples of natural foodstuffs (mushrooms and berries) were found in 2013 to be much lower than corresponded permissible levels. Values of the ³H specific activity for the water samples from the surface and underground sources sampled in 2013 decreased more than in 1,5 times in comparing with 2008 and have not exceeded the interventional level – 7600 Bq/kg. Exposure doses estimated for the critical group of population Exposure doses estimated in 2013 for the critical groups of population have not exceeded the dose limit adopted in RSS-99/2009. The interest of population to the mentioned problem has not been pointed out on the basic of the analysis of publications electronic versions in mass media for 2013. The comparative analysis of the results of the survey showed that level of public concern over the radiation environment in their places of residence has been low in 2008 and even lower in 2013. With a low level of the knowledge concerning radiation respondents found their significant interest for the issues relating radiation, its effects on the health and radiation protection measures.

Along with the radiation-hygienic monitoring, it is necessary to conduct regular activities aimed on the population informing about the radiation situation on the basic of the significant data obtained from the responsible agencies specialists.

The purpose. The purpose of the investigation is an assessment of the peculiarities of forming and registration of the collective doses of patients and the population of the Tatarsatan Republic (RT) from medical exposure and the development of measures for optimization of this radiation factor.

Materials and methods. The analysis is based on the forms of the Federal statistical observation № 3-DOZ «Data on the exposure doses to patients obtained during medical radiological examination» (form № 3-DOZ) and radiation-hygienic passports of RT for the period from 2006 to 2013.

The results. Annually in RT there is an increase of the number of performed X-ray procedures, which reached the value of 6279696 (1.64 procedures per resident per year) in 2013. During the reporting period (from 2006 to 2013) the structure of the performed X-ray procedures has also changed. It is observed that the percentage of fluorography procedures in the overall structure decreased from 41.3% to 31.3% at the same time the level of absolute value of annually performed fluorography procedures is stable. There is an increase in the absolute number of radiographic procedures performed during the period from 2578754 to 4072810 X-rays per year, that is 1.58 times higher. Absolute and relative values related to X-ray fluoroscopy examinations decreased from 1.1% to 0.7%. In contrast, the absolute number of annually performed X-ray computed tomography examinations (CT) has increased over the period by 3.3 times and percentage of CT in overall structure of X-ray procedure is 2.7%. The number of special investigations has increased in 2.1 times, but the relative value remained at average level of 0.4% on general background of the increasing of X-ray activity in the region. This fact influenced the change in the radiation-hygienic indexes of medical radiation exposure of the population of RT. According to №3-DOZ forms and radiation-hygienic passports of the territories, the levels of the annual collective effective dose from medical exposure to the patients and population increases in the period from 2006 to 2012. The structure of the medical exposure has been significantly changed. If the dominant role in the formation of the annual collective effective dose in 2006 performed the fluorography procedures (609.17 person-Sv; 34.03% in the structure of the total collective dose from medical exposure), then the primary importance passed to СТ in 2013 (748.18 person-Sv; 50.04%). The article considers the peculiarities of the formation and recording of exposure doses to patients when performing various types of x-ray procedures.

Conclusion. The widespread use of the digital technologies of producing and processing of the X-ray images, an adjust instrumental control and registration of patient exposure doses, routine control of operational parameters of the equipment used for the fluorographic, X-ray and fluoroscopic procedures allowed to objectify and reduce correspondent indicators of the collective effective exposure doses to patients and population. There exists the reserve for organizational, technical measures for the further reduction of patient exposure doses during the performance of the routine X-ray procedures, namely the standardization of the performed examinations, further transition to the digital X-ray technologies of the image obtaining. The use of calculation methods of the patient dose registration continues to provide the significant influence on the statistical reporting when the performing of CT and special examinations. Taking into account the fact that CT provides the greatest contribution to the annual collective effective dose in the region in recent years (more than 50%, the first place in the structure of medical exposure), and special examinations of a high clinical efficient, are also accompanied by a significant radiation exposure it is necessary to apply the measures fore the objectification of the exposure doses for these types of examinations in order to develop scientifically justified measures to reduce adverse effects on the exposed population categories.

To explain the known differences in the dose and age dependences of radiogenic mortality from leukemia and solid tumors after single exposure, a model was developed, which is a modification of the Kellerer-Rossi theory of dual radiation action. The model assumes formation in a cell of both single and double primary damages due to radiation and other carcinogens, while the recovery rate of single damages (φ) significantly exceeds that for double ones (ψ). Upon achieving a certain stage of the cell cycle (the critical age of cell – T), double damages become permanent and with probability of А can be inherited to daughter cells as “premalignant” defects. In contrast, in the Kellerer-Rossi theory, permanent damage is formed immediately after formation of the second damage at the next energy absorption event in the cell, i.e. ψ=0 .

On the assumption that the premalignant defects only occur based on the double primary damages, i.e. φ>>ψ, the expressions for А were derived for the prompt radiation exposure and radiation exposure at a constant dose rate. They reproduce the effect increasing with decreasing of T, whereas the influence of T on the linear term of the dose expression in both cases is the same, but with decreasing of T the quadratic term increases faster for exposure at a constant dose rate than that for the prompt one. Thus, presence of the quadratic term in the dose expression for leukemia and its virtual complete absence for solid tumors may be due to lower T-value for hemopoietic stem cells. Predicted by the model dose rate influence on the quadratic term does not depend on the dose, so the reduction factor should be only applied to the quadratic term of the dose expression. This follows as well from the original version of the Kellerer-Rossi theory.

The Third complex multidisciplinary expedition of the Russian Geographic Society for monitoring of the radiation situation in the Kuril-Kamchatka area of the Pacific Oceantook place in September – October 2014. The purposes of the expedition were monitoring of the radiation situation and assessment of the impact of the accident at the nuclear power plant “Fukushima-1”on radioactive contamination of the marine environment near the Russian coasts. This paper presents results on the activity measurements of the cesium and strontium radionuclides in the hydrobionts collected during the expedition in the Seas of Japan and Okhotsk. Nine samples of the sea hydrobionts including one species of invertebrates and four species of fish have been analysed. Determination of activity concentrations of radionuclides of cesium (separately ¹³⁴Cs and ¹³⁷Cs) were carried out by the gammaspectrometry method using a high-resolution semiconductor detector. Activity concentrations of ⁹⁰Sr were quantified with a radiochemical method. The activity concentrations of ⁹⁰Sr and the total activity concentrations of both cesium radioisotopes for all the samples analyzed did not exceed 1 Bq kg^–1 (wet weight). This value is much lower than the safe levels of 130 Bq kg–1 (radiocesium) and 100 Bq kg^–1 (radiostrontium) for the fish consumption inRussia. The study demonstrates that theFukushima accident has no considerable impact on radioactive contamination of the selected species of hydrobiota in Russian waters of theJapanSea andOkhotskSea.

There have been provided an analysis of the digitized full-text abstracts and dissertations on the official websites of institutions with dissertation councils on hygiene, in the digital libraries of the Russian State Library (RSL) and the National Library of Russia (NLR) and the website of the Higher Attestation Commission at the Ministry of Education. An array was formed of 1446 theses on the specialty 14.02.01 (old code – 14.00.07) «Hygiene» for 2000–2012. Doctoral theses comprised 19.8 % – significantly more than cumulative biological and medical theses (14.8 %) for the same period inRussia. Polynomial trend with a coefficient of determination (R2 = 0.73) with statistical significance indicates a decrease in the number of theses. Every year inRussiadissertation councils on hygiene received (111 ± 9) theses. It is established that in 76.9 % of abstracts are digitized in NLR and 63.7 % in RSL. Digitized documents can be accessed in the halls of the library for free, and in a mode of remote access – for a fee. Measures to optimize dissertation documents digitizing by librarians are described, as well as to seek opportunities to create a unified information system of dissertation research in Russia in the Scientific Electronic Library within the reference-analytical system Science Index for dissertation councils, free subscription of national research libraries to digital full-text databases of abstracts and dissertations and integration of Russian scientists in the international scientific community.

An article presents the modern problems of population radiation protection inBashkortostanRepublic. The main natural ionizing irradiation sources are identified and their contribution to the total exposure dose of the BashkortostanRepublicpopulation is analyzed. The types of the main natural ionizing irradiation sources are identified, as well as the ways of their intake and the methods of their influence. The results of laboratory studies are presented for the radon equivalent equilibrium volumetric activity, for the average gamma radiation dose rate in dwellings, for the investigations of gross alpha and gross beta activity in drinking water and open water sourcesBashkortostanRepublic. The article underlines the main problems of the radiation situation in the new construction. The main preventive measures are pointed out for the radiation protection of the buildings under construction improving. The article also presents an analysis of the results of activities of the Administration of Rospotrebnadzor in theBashkortostanRepublicfor the reducing of the levels of the Republican population exposure from the natural irradiation sources.