Post-accident Period Research Articles

Psychosocial state of the adult evacuees and risk factors of negative change

Study and evaluation of psychosocial state of population evacuated from the 30 km ChNPP zone at the age of 18 years and older; identification of potential psychosocial risk factors for the health loss. The sampling epidemiological study of psychosocial state of population aged 18-50 years evacuated from the 30 km zone of ChNPP was conducted at the NRCRM Radiation Registry Outpatient Clinic and Radiation Psychoneurology Department. The study subjects (n=258) were mostly (98%) females. Study was con ducted from October 2013 till May 2015. All the sample members were registered since 1992 in the system of life long health monitoring, i.e. the NRCRM Clinical and Epidemiological Registry. Study subjects were interviewed through the method using an original «Questioning Inventory». Mathematical processing of study results was held using the Epi Info 7 software package. According to the study results, a nuclear accident at the Chornobyl NPP has become a powerful psychoso cial stress for evacuated people. Psychosocial state of the evacuees, formed during the post accident period, with full reason can be defined as a state of stable, chronic psychosocial stress. Nature of factors that caused the stress development is polygenic. Block of stressors directly related to the accident was determined, namely there were «change of radiation and ecological situation», «ionizing irradiation», «evacuation», and «radical breaking of dynamic stereotype of behavior and life». In parallel there was selected a block of stress factors generated by that background, i.e. psychological, social, economic, and cultural, on which a nuclear disaster was imposed upon. The effects of stress have manifested as a persistent syndrome of «anxiety» for the personal health and health of fami ly members, primarily the children, and as a stable state of «dissatisfaction» with fullness and quality of life. The nuclear accident at the ChNPP has been the cause of a strong psychosocial stress in adult evacu ated population, especially in women. Further in a remote period the stress was transformed into a stable, chronic form. Nature of stress is polygenic and includes stressors directly related to the accident, and stressors that are not directly related to the accident consequences, but are due to the level of social, economic, medical, and informa tional protection of survivors. Data presented in the paper are rather enough important for the formation of strate gies and measures for social and psychological protection of population in an event of nuclear accidents and incidents.

Cardiovascular diseases and systolic function of left ventricle in clean-up workers of Chornobyl accident (based on 30 years follow-up)

To study the dynamics of circulatory system diseases during the 30 year period after irradiation, changes in the status of systolic function of heart left ventricle (LV) and the features of its remodeling in clean up workers (CW) of the accident at the Chernobyl nuclear power plant (ChNPP). It was examined 144 CW at ChNPP, including 52 patients, who survived acute radiation sick ness (ARS) grade of severity 1-3, and 105 non irradiated persons (control group - CG). CW have been divided into two subgroups: without signs of ARS (ARS0) and those who suffered from ARS. CW and CG patients were male who had no signs of cardiovascular, nervous, pulmonary or endocrine pathology prior to the Chernobyl accident. Their average age at the beginning of the accident was 33.9-37.7 years. The study program included clinical examina tion, echocardiography, retrospective and statistical analysis. Hypertensive heart disease (HHD) has developed in the CW, including the ARS convalescents, by 12 years, and ischemic heart disease (CHD) at 9-11 years is believed to be earlier than in comparable non irradiated patients. In the post accident period, there was an increased mean value of LV posterior wall (PW) thickness, interventricular septum (IVS), myocardium mass and myocardium mass normalized by body surface area. These indices grew with the increase of HHD duration. Over the 30 year follow up period, between CW and CG from 14.3 to 28.6 % of patients with LV increased volumes it was found a decreased ejection fraction (EF), what indicated the development of sys tolic LV dysfunction with the phenomena of left ventricular heart failure (HF). Reduction of EF correlated with increase of end systolic volume (ESV) having the highest statistical strength. In CW and persons of CG there was from 77.3 to 84.8 % of patients had clinical signs of HF with preserved EF. From this number, 56-63.6 % of patients had concentric and 18.8-26.7 % had eccentric LV hypertrophy (LVH), and in 6.1 to 15.6% of patients, normal LV geom etry or its concentric remodeling was observed. The CW and non irradiated persons differed significantly by the onset of HHD and CHD, which previ ously developed in the CW, including the ARS survivors. Changes in the structural and functional state of myocardi um during long term follow up did not have any probable differences between CW and non irradiated persons and consisted of BW and IVS thickening, which predetermined the development of LVH. In CW and CG concentric LVH was dominant. The LV systolic dysfunction with decreased EF and increased ESV was characterized by clinical symptoms of left ventricular HF. More than half of patients with clinical symptoms of HF and preserved EF had signs of concen tric hypertrophy.

Reconstruction of individualized doses of subjects from the Ukrainian State Register – of Persons that Affected due to Chornobyl accident and reside in Korosten raion of Zhytomyr oblast

To elaborate an ecological dosimetric model of reconstruction individualized exposure doses of subjects from the State Register of Ukraine (SRU) - of persons, affected due to Chornobyl accident and reside at the radioactive contaminated territory of Korosten raion of Zhytomyr Oblast, and to calculate exposure doses for those persons. In the paper, an ecological dosimetric model is presented which is elaborated in order to individualize exposure doses of people who reside in Korosten raion of Zhytomyr Oblast and are registered in SRU. The model is based on the results of radio ecological and dosimetric monitoring held in the period of 1986-2013 at the territory of northern oblasts of Ukraine. Annual dose over each post accidental year consists of the two compo nents: (a) annual effective dose of external gamma exposure (due to radioactive fallout on the ground), and (b) internal exposure of the whole body (due to consumption of meal contaminated by radioactive isotopes). For 1986, the dose of internal exposure is evaluated out of all main radionuclides of radioactive accidental fallout, and after 1987 only for radioisotopes of caesium (134Cs and 137Cs). The parameterization of the model is based on the pre vious experience in working out a complex of ecological dosimetric models for estimation of referent exposure doses of Ukrainian population. Individualized doses of external and internal exposure (annual and accumulated) are estimated for the population of various age groups that resides in the settlements of Korosten raion (totally about 100 settlements). Separately the doses are presented for rural settlements of the raion and for the city of Korosten for each year of the post accidental period of 1986-2016. Estimates of doses are given that were accumulated: (a) during 15 years just after the accident, (b) for the period of 2000-2016, and (c) for 30 year period after the acci dent. Mean dose accumulated for 30 years after the Chornobyl accident by residents of rural settlements of Korosten raion is estimated as 19.8 mSv, and for inhabitants of the Korosten city as 20.9 mSv. On condition of permanent res idence in the raion, residents of about 66 % settlements of Korosten raion accumulated the doses in the interval 5 20 mSv during 30 years after the accident. For the residents of about 25 % settlements the accumulated dose is in the interval 20-50 mSv, and for 7 % of settlements it exceeds 50 mSv.

Industrial disasters: the Seveso accident and its 40-year legacy

The 1976 disaster in Seveso, Italy left a legacy of utmost relevance and contributed to a major shift in the way society, people and industry consider the environment-and-health issue. Main aspects of this legacy concern policy, science, research and the community. Policy: The accident prompted the adoption in 1982 of EU legislation on the prevention and control of major-accident hazards of certain industrial activities, the ‘Seveso-Directive’, later amended in 1996 and in 2012 to take into account increased rights for citizens to access information and justice. Science: The accident represented an unplanned ‘experiment’ providing further insight into the effects of 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) in humans. An increased risk was seen for lymphohematopoietic neoplasms in the thirty-year post-accident period; all-cancer incidence was increased in a subset of highly exposed women; suggestive, non-consistent increases were seen for colorectal and breast cancer. Diabetes was more frequent in the exposed area. In families with very high TCDD serum concentrations, the M/F ratio at birth was inverted; the number of females being larger than males. The male reproductive system appeared critically sensitive to TCDD. Women’s fertility and second generation studies are underway. Research: Seveso made it clear that for a complete health impact assessment, in addition to chemical exposure, the post-disaster stressful experience, the personal and community characteristics and the measures implemented to respond to the disaster should be considered: The increased cardiovascular mortality among men in the most polluted area, in the early post-accident period, points towards post-disaster stress as a major health determinant. Community: People need not only to be protected, but also to play an active role in the response and recovery phases. Communication and participation avoid mistrust, control stressful factors and foster population resilience.

Analysis of the Dynamic Behavior and Stress-Strain State of NPP Containment under Nonstationary Impacts

The paper presents the analysis of dynamic behavior of the reinforced concrete containment of NPP unit under the combined effect of internal pressure shock caused by the accident in the reactor hall and seismic impact of design-basis earthquake using the finite element method (FEM) and DIPROS software. Using the modal analysis and numerical solution of the FEM equations of containment concrete, the stress-strain state of the building structure in the post-accident period was defined. It is shown that the maximum intensity of the stresses in the steel liner of the containment does not exceed the yield strength of the steel liner material. Accordingly, the liner integrity is preserved, the containment remains operable and ensures compliance of radiation safety requirements.

Radiological dose reconstruction for birds reconciles outcomes of Fukushima with knowledge of dose-effect relationships.

We reconstructed the radiological dose for birds observed at 300 census sites in the 50-km northwest area affected by the accident at the Fukushima Daiichi nuclear power plant over 2011–2014. Substituting the ambient dose rate measured at the census points (from 0.16 to 31 μGy h−1) with the dose rate reconstructed for adult birds of each species (from 0.3 to 97 μGy h−1), we confirmed that the overall bird abundance at Fukushima decreased with increasing total doses. This relationship was directly consistent with exposure levels found in the literature to induce physiological disturbances in birds. Among the 57 species constituting the observed bird community, we found that 90% were likely chronically exposed at a dose rate that could potentially affect their reproductive success. We quantified a loss of 22.6% of the total number of individuals per increment of one unit log10-tansformed total dose (in Gy), over the four-year post-accident period in the explored area. We estimated that a total dose of 0.55 Gy reduced by 50% the total number of birds in the study area over 2011–2014. The data also suggest a significant positive relationship between total dose and species diversity.

HYPERTENSIVE HEART DISEASE IN THE ADULT POPULATION EVACUATED FROM THE CHERNOBYL EXCLUSION ZONE IN THE POST-ACCIDENT PERIOD

Objective: to determine the level of nosologic forms of hypertension disease (HD) in the population resettled from the Chernobyl exclusion zone to show its dependence on age, sex and the period of time the people lived in the zone before the resettlement. Material and methods. The data on the age of the cohort at the time of the accident were studied over 1988-2010 (30779 people at the age 18-39, 24343 people at the age 40-60). The research included epidemiological and statistical methods. Results. The post-accident period is characterized by the increased prevalence of cardiovascular diseases. The people whose age at the time of the accident was 18-39 detected the highest morbidity rate 17-22 years after the accident, and the people aged 40-60 at the time of the accident detected a high morbidity rate for the first time 6 years later and the maximum rate was 12-17 years later. The HD morbidity rate in the people whose age was 18-39 with the exception of the first period after the disaster was slightly higher than in the people from the older age group. During the first two accident periods, the patients diagnosed with essential HD were prevalent, which can be explained by the impact of stress and social and economic factors. Beginning from the third period, the morbidity of HD, mainly affecting the heart, has become more substantial and remained its high rate.

Exposures and effects in the marine environment after the Fukushima accident.

This paper does not necessarily reflect the views of the International Commission on Radiological Protection. Radiation doses to marine biota near the Fukushima Daiichi nuclear power plant have been estimated for the immediate aftermath and subsequent period of the accident. Dose estimations using monitoring data have been complemented by means of dynamic transfer modelling, improving on the more traditional equilibrium transfer approach. Earlier assessments using equilibrium transfer models overestimated the exposures in the immediate aftermath of the accident, whereas dynamic transfer modelling brings them more in line with the doses calculated from monitored activity concentrations in the biota. On that basis, marine biota populations in the vicinity of Fukushima do not seem to be at significant risk. The situation in the late post-accident period shows a tendency for lower exposures, but radiocaesium in sediments and biota persists to this day, with some organisms inhabiting local hotspots. Little is known about how long radionuclides will continue to remain in the local environment, or the long-term effects on populations due to limited knowledge on the effects of chronic radiation exposures to marine organisms. Therefore, the marine environment at Fukushima needs further study. The Fukushima nuclear accident remains an ongoing problem for marine radioecology, requiring constant re-evaluation of the cumulative extent of contamination and effects on the environment for years to come.

Postaccident changes in health status of the Chornobyl cleanup workers 1986–1987 (period of observation 1988–2012)

To determine postaccident changes in health status of the Chornobyl cleanup workers 1986 1987, pecu liarities of nontumor incidence. Long term cohort epidemiological study (period of observation 1988-2012) has been con ducted using data of the State Registry of Ukraine of Persons Affected by the Chornobyl Accident. Study cohort - 196,423 males participants of the Chornobyl recovery operations in 1986-1987. Epidemiological and mathematical and statistical methods were used. We have found a dramatic deterioration of the Chornobyl cleanup workers' health due to the growth of wide range of nontumor diseases, especially circulatory, digestive, respiratory, endocrine, genitourinary and nervous sys tem diseases. In postaccident period, disability and mortality have increased significantly due to nontumor dis eases. Circulatory diseases make major contribution to the structure of causes of disability and death. When study ing the dynamics of nontumor incidence, we have found that in 1988-1992 the highest, throughout postaccident period, rate of mental and behavioral disorders, diseases of the nervous system was mainly due to disorders of the autonomic nervous system. Since 1993-1997, rate of this pathology has significantly reduced and remained stable in subsequent years of observation. Thus, we can assume that in the early postaccident period, stress factor in com bination with radiation one had the greatest impact on health of cleanup workers, resulting in the development of other nontumor diseases in the remote postaccident period. The study revealed an evident increase in nontumor incidence, disability and mortality from nontumor diseases among Chornobyl cleanup workers 1986-1987; the highest rate of nontumor incidence was observed 12-21 years after the Chornobyl accident.

Basic principles and practices of integrated dosimetric passportization of the settlements in Ukraine

The purpose of the review is to demonstrate the results of dosimetric passportization (performed in 1991-2014) for the settlements of Ukraine which suffered from radioactive contamination caused by the Chornobyl accident. The dosimetric passportization played a key role in the National program on the liquidation of aftermath of the Chornobyl accident directed on recovery through all stages of the current radiation situation control and decision support touching upon various types of interventions and social benefits to the population of radioactively contaminated areas. The works being performed under dosimetric passportization did not have analogues among the researches which took place after other large-scale industrial and municipal accidents as well their scales as the duration of both radio-ecological and dosimetric monitoring.The new methodological approaches to the assessment of so-called passport doses of a settlement as well as to the definition of the concept of annual dose being the dose used to make decisions for providing both direct and indirect emergency countermeasures for the settlements of Ukraine became pioneering ones. During all the post-accident period there were issued sixteen collections of general dosimetric passportization data which accumulate the results of hundreds of thousands spectrometric, radiochemical and radiation levels measurements and WBC measurements carried out in 1991-2014.The annual passport doses calculated on the basis of these measurements (including their components) are unique information that quantifies the level and time dynamics of the radiation situation for each of the 2161 settlements of 74 raions in 12 oblasts during all the post-accident period. Thanks to the works of dosimetric passportization of the settlements of Ukraine there were created databases to be unique in their structure and content with quantitative characteristics of the territorial and temporal distribution, the dynamics of changes of a number of important radiological parameters, namely over 500 thousands of measurements of concentration of 137Cs and 90Sr in the local foodstuff (milk and potatoes); there are more than 1.3 million of measurements of the cesium content in the body of residents of the settlements of Ukraine; there are 100 thousands of dose estimates (both internal and external ones were measured separately) of inhabitants living on the radioactively contaminated areas. The results of the dosimetric passportization served as one of the main exposure criteria for generalized aftermath of the Chornobyl accident represented in the National reports for the first 15, 20 and 25 years after the accident.

Experience of study of the incidence of malignant neoplasms population in small areas of Ukraine, which suffered contamination with radionuclides due to the Chornobyl accident

to evaluate the dynamics of implementation risks of malignant tumors in some small areas of Ukraine in the pre- and post-accident period. The study population group - the population of the Malyn rayon, Zhytomyr region. The period of observation covered 1980-2014. There was investigated the incidence of malignant tumors in general and individual nosological forms (thyroid cancer, breast cancer, tumors of hematopoietic and lymphoid system). Methods of variation statistics and descriptive epidemiology were used. Characteristics of ionizing radiation influence on the population of Malyn rayon indicate the potential for negative effects, especially for thyroid cancer. Besides the fact that the average total effective radiation dose whole body by radioactive cesium in Malyn rayon population (5.9 mSv) are at medium level in Zhytomyr region and is significantly lower in comparison with those of other areas of the northern part of the oblast, the exposure of thyroid 236 mGy, is significantly higher than the regional figures - 81 mGy. Although the level of morbidity Malyn rayon of malignant tumors in general was about at the national level for 1999-2003 and lower it in the 2012-2014, exceeding the figures of Zhytomyr region, the incidence of thyroid cancer in the 2012-2014 in Malin area was 1.7 times higher in comparison with data for Ukraine and in 1.9 times in comparison with the data in Zhytomyr region. As in most northern areas that fell under radioactive iodine fallouts, there is the realization of increased radiation risk of cancer of this organ. The incidence of breast cancer in female population Malyn rayon is the lowest in comparison with Ukraine and Zhitomir regions. However, the rate of increase in this area is the highest. The results indicate the need for further monitoring of occurrence of cancer cases in the population of not only Ukraine as a whole, or large administrative units, but also among the population in small areas, taking into account the probability of the realization of risks of radiation-associated disease cases according to local environmental conditions.

The dynamic nature of risk perceptions after a fatal transit accident.

In 2009, two trains of Washington, DC's Metrorail system collided, resulting in nine deaths and 50 serious injuries. Based on a multiwave survey of Metrorail users in the months after the crash, this article reports how the accident appears to have (1) changed over time the tradeoffs among safety, speed, frequency of service, cost, and reliability that the transit users stated they were willing to make in the postaccident period and (2) altered transit users' concerns about safety as a function of time and distance from the accident site. We employ conditional logit models to examine tradeoffs among stated preferences for system performance measures after the accident, as well as the influence that respondent characteristics of transit use, location, income, age, and gender have on these preference tradeoffs. As expected, respondents appear averse to longer headways between trains, longer travel durations, higher travel costs, a higher number of late trains, and a higher number of fatalities. The models also show evidence of higher aversion to fatalities from transit system operation among females compared to males. In addition, respondents less experienced with Metrorail travel and those with lower household incomes show higher aversion to fatalities, and this aversion increases as a subject's psychological distance from the accident site decreases. Contrary to expectations shaped by previous studies, aversion to fatalities appears to have increased between the early months after the accident and the end of the survey period, and the expected relationship between age and aversion to fatalities is not statistically significant.

Структурні зміни щитоподібної залози в постраждалих внаслідок аварії на ЧАЕС, хворих на цукровий діабет 2-го типу

Відповідно до мети роботи нами було проведено дослідження клінічних зв’язків між цукровим діабетом (ЦД) 2-го типу та незлоякісними захворюваннями щитоподібної залози (ЩЗ) у потерпілих внаслідок аварії на Чорнобильській атомній електростанції (ЧАЕС) у віддалені поставарійні терміни (148 осіб) та в контрольній групі (38 осіб). Отримані дані стосовно характеру та частоти органічної патології ЩЗ. Частота органічної патології ЩЗ у хворих на ЦД 2-го типу, потерпілих внаслідок аварії на ЧАЕС (58,3 ± 6,3 %), статистично вірогідно (р < 0,05) вище, ніж у групі контролю (43,1 ± 3,9 %). Домінуючою патологією у хворих на ЦД 2-го типу, потерпілих внаслідок аварії на ЧАЕС, є вузловий еутиреоїдний зоб, частота якого (26,7 ± 5,7 %) більше ніж в 3,3 раза вища (р < 0,01), ніж у групі контролю (8,1 ± 2,2 %), та залежить від статі, віку, тривалості основного захворювання.

Insight from Fukushima Daiichi Unit 3 Investigations Using MELCOR

During the emergency response period of the accidents that took place at the Fukushima Daiichi nuclear power plant (NPP) in March of 2011, researchers at Oak Ridge National Laboratory (ORNL) conducted a number of studies using the MELCOR code to help understand what was occurring and what had occurred. During the postaccident period, the U.S. Department of Energy (DOE) and the U.S. Nuclear Regulatory Commission (NRC) jointly sponsored a study of the Fukushima Daiichi NPP accident with collaboration among ORNL, Sandia National Laboratories, and Idaho National Laboratory. The purpose of the study was to compile relevant data, reconstruct the accident progression using computer codes, assess the codes’ predictive capabilities, and identify future data needs. The current paper summarizes some of the early MELCOR simulations and analyses conducted at ORNL of the Fukushima Daiichi NPP Unit 3 (1F3) accident. Extended analysis and discussion of the 1F3 accident are also presented taking into account new knowledge and modeling refinements made since the joint DOE-NRC study.

Interpreting aerosol lifetimes using the GEOS-Chem model and constraints from radionuclide measurements

Abstract. Aerosol removal processes control global aerosol abundance, but the rate of that removal remains uncertain. A recent study of aerosol-bound radionuclide measurements after the Fukushima Daiichi nuclear power plant accident documents 137Cs removal (e-folding) times of 10.0–13.9 days, suggesting that mean aerosol lifetimes in the range of 3–7 days in global models might be too short by a factor of two. In this study, we attribute this discrepancy to differences between the e-folding and mean aerosol lifetimes. We implement a simulation of 137Cs and 133Xe into the GEOS-Chem chemical transport model and examine the removal rates for the Fukushima case. We find a general consistency between modelled and measured e-folding times. The simulated 137Cs global burden e-folding time is about 14 days. However, the simulated mean lifetime of aerosol-bound 137Cs over a 6-month post-accident period is only 1.8 days. We find that the mean lifetime depends strongly on the removal rates in the first few days after emissions, before the aerosols leave the boundary layer and are transported to altitudes and latitudes where lifetimes with respect to wet removal are longer by a few orders of magnitude. We present sensitivity simulations that demonstrate the influence of differences in altitude and location of the radionuclides on the mean lifetime. Global mean lifetimes are shown to strongly depend on the altitude of injection. The global mean 137Cs lifetime is more than one order of magnitude greater for the injection at 7 km than into the boundary layer above the Fukushima site. Instantaneous removal rates are slower during the first few days after the emissions for a free tropospheric versus boundary layer injection and this strongly controls the mean lifetimes. Global mean aerosol lifetimes for the GEOS-Chem model are 3–6 days, which is longer than that for the 137Cs injected at the Fukushima site (likely due to precipitation shortly after Fukushima emissions), but similar to the mean lifetime of 3.9 days for the 137Cs emissions injected with a uniform spread through the model's Northern Hemisphere boundary layer. Simulated e-folding times were insensitive to emission parameters (altitude, location, and time), suggesting that these measurement-based e-folding times provide arobust constraint on simulated e-folding times. Despite the reasonable global mean agreement of GEOS-Chem with measurement e-folding times, site by site comparisons yield differences of up to a factor of two, which suggest possible deficiencies in either the model transport, removal processes or the representation of 137Cs removal, particularly in the tropics and at high latitudes. There is an ongoing need to develop constraints on aerosol lifetimes, but these measurement-based constraints must be carefully interpreted given the sensitivity of mean lifetimes and e-folding times to both mixing and removal processes.

Changes in pediatric thyroid sonograms in or nearby the Kanto region before and after the accident at the Fukushima Daiichi nuclear power plant.

Following the accident at the Fukushima Daiichi Nuclear Power Station which occurred on March 11, 2011 due to the Eastern Japan Great Earthquake (the Accident), there have been concerns over elevation of the risk of thyroid cancer among children due to internal exposure to radioactive iodine. In Fukushima Prefecture, screening of children with thyroid ultrasonography has been carried out, yielding numerous findings, suggesting a possible influence from the Accident. We report thyroid ultrasonographic findings, used by similar device at Fukushima Prefecture's study, at Ito-hospital. Of the 2721 children aged 15 or less who visited our hospital between January 2005 and March 2013, 1214 children (330 boys and 884 girls; median age, 12; range of age, 4-15) were covered by evaluation of thyroid ultrasonographic findings, excluding children known in advance to have thyroid disease on the basis of disease history, palpation and blood tests. Among these 1214 children, 709 children (58.4%) were found cysts (≤ 5 mm in 665 cases) by ultrasonography, 43 children (3.5%) were found nodules (≤ 5 mm in 18 cases) and 9 children (5.2%) were found an intrathyroid ectopic thymus. Analysis of the data before and after the Accident using the same device, involving age adjustment on the basis of the standard population in 2010, showed no difference in the incidence rate of cysts or nodules. In children examined, the incidence rate of cyst formation (particularly ≤ 5 mm) was higher, and there was no difference in the incidence rate of cysts or nodules between the pre- and post-accident period.

Distribution and migration of 90Sr in components of the Dnieper River basin and the Black Sea ecosystems after the Chernobyl NPP accident

The change in 90Sr concentrations in hydrobionts, water and bottom sediments of the Chernobyl NPP pond-cooler, the Kievskoe and Kakhovskoe reservoirs, the Northern-Crimean canal and the Black Sea after the Chernobyl NPP accident was studied. The environmental half-times for the decrease of 90Sr concentrations were determined: in water – 4.1–24.3 years; algae and flowering water plants – 3.6–7.7 years, in molluscs – 2.4–6.7 years, and in fish – 7.8–12.9 years. The time for 90Sr concentrations to decrease to pre-accident levels were estimated: in freshwater reservoirs and the northwest part of the Black Sea this was 32–44 years, and in freshwater hydrobionts this was 25–73 years. The contribution of dose from 90Sr to the hydrobionts, sampled from the Kakhovskoe reservoir, the Northern-Crimean canal and the Black Sea, has not reached values which could impact them during the entire post-accident period. This complex of comparative studies was carried out for the first time.

Differences in the expression profiles of normal contralateral tissues of papillary thyroid cancer patients exposed and not exposed to the Chernobyl fallout

The change in 90Sr concentrations in hydrobionts, water and bottom sediments of the Chernobyl NPP pond-cooler, the Kievskoe and Kakhovskoe reservoirs, the Northern-Crimean canal and the Black Sea after the Chernobyl NPP accident was studied. The environmental half-times for the decrease of 90Sr concentrations were determined: in water – 4.1–24.3 years; algae and flowering water plants – 3.6–7.7 years, in molluscs – 2.4–6.7 years, and in fish – 7.8–12.9 years. The time for 90Sr concentrations to decrease to pre-accident levels were estimated: in freshwater reservoirs and the northwest part of the Black Sea this was 32–44 years, and in freshwater hydrobionts this was 25–73 years. The contribution of dose from 90Sr to the hydrobionts, sampled from the Kakhovskoe reservoir, the Northern-Crimean canal and the Black Sea, has not reached values which could impact them during the entire post-accident period. This complex of comparative studies was carried out for the first time.

THE FORMATION PRINCIPLES OF INCREASED RADIATION RISK GROUPS AMONG THE CHERNOBYL-AFFECTED POPULATION REGISTERED IN THE BELARUSIAN STATE REGISTRY

Using the State Registry database there was composed the group including all people who stayed in the evacuation zone during the early post accident period not taking into account to what group of the primary account they belonged to. The provided analysis of the State Registry data about the population staying in the evacuation zone during the early post accident period showed that the dose filling of the existing databases is of current importance from the scientific and practical point of view. The using of place and terms of staying in the radiation exposure zone criteria not depending on the group of the primary account including the filling of databases with existing dosimetry information are considered to be the adequate ones for formation of groups with various dose burdens. The suggested approach can serve as the basis for optimization of the medical provision for the affected population on frequency and amount of treatment-diagnostic manipulations and also for providing long-term radiation-epidemiological studies.

CHERNOBYL RADIONUCLIDE DISTRIBUTION, MIGRATION, AND ENVIRONMENTAL AND AGRICULTURAL IMPACTS

The distribution and migration of radionuclides released into the environment following the Chernobyl accident in 1986 are described. The Chernobyl disaster resulted in the consumption of farm products containing radionuclides as a source of irradiation of the population due to the prevalence of a rural type of human nutrition in the affected region. Economic and radiologic importance of countermeasures for reducing the impacts of the accident are described. The basic radioecological problem is described in which the area where direct radiation contamination of biota was observed is considerably smaller than the zone where concentrations of radionuclides through the food chain exceeded the permissible standards. The radiation-induced effects in biota in the affected area are described. In the long-term post-accident period, the radionuclide distribution between components of ecosystems (including humans) and doses are considered in comparison to a technologically normal situation of nuclear power plant operation. This analysis demonstrates that if radiation standards protect humans, then biota are also adequately protected against ionizing radiation.