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Concept of seasonality in the light of the Chernobyl accident.

Seasonality could have a strong influence on the radiological impact of environmental radioactive contamination. Short-lived radionuclides (e.g., 131l) and those that mainly enter the food chain by direct contamination (e.g., 137Cs) are especially important in this context. In particular, the contamination of cereals is influenced by seasonality. For temperate latitudes it is generally true that radioactive contamination during winter, when the fields lie fallow and the domestic animals are stabled, will result in a significantly lower radiological impact than if a similar contamination were to take place in the summer shortly before harvesting. The impact of the Chernobyl accident on the radioactive contamination of human diet was strongly influenced by seasonality.

Accidents↗

Investigations of radiocaesium in the natural terrestrial environment in Norway following the Chernobyl accident.

Radioactive fallout from the Chernobyl accident affected parts of central Norway to a considerable extent, in particular the 134Cs+137Cs deposition had a significant impact on the natural environment. When this became apparent, a comprehensive radioecological research programme was initiated in order to study the behaviour of radiocaesium in boreal and alpine ecosystems, with emphasis on food-chains leading to exposure of species used for human consumption, i.e., reindeer and freshwater fish. In this paper results from the terrestrial part of this research programme during the period 1986-1990 are presented. The work was mainly confined to the mountain areas of Dovre and Rondane. Parallel studies were performed in eutrophic and strongly oligotrophic communities. The influence of local variations in topography and microclimate on the observed radiocaesium levels in topsoils, lichens and vascular plants was studied in detail. Currently a significant re-distribution of radiocaesium from the originally strongly exposed surfaces to those that were less exposed is observed. In the soil, radiocaesium is strongly retained in the litter and raw humus layers. Current levels in lichens are 1-2 orders of magnitude higher than in vascular plants. This strongly affects the seasonal variation of radiocaesium in reindeer, showing winter maxima of about 5 times higher than the August levels. The radiocaesium levels in reindeer showed a decline of approximately a factor of 3 during the period 1987-1990. Other animal species studied in the programme exhibited substantially lower radiocaesium levels than reindeer, but a considerable interspecies variation was observed.

Accidents↗

Winter transport of Chernobyl radionuclides from a montane catchment to an ice-covered lake.

The amounts of 137Cs and 90Sr have been determined in the inflows and outflows of the Norwegian sub-alpine lake, Ovre Heimdalsvatn, in March/April during the period of ice-cover, when discharge is extremely stable. The lake is situated in an area contaminated by Chernobyl fallout. The transported course particulate plant material has been collected in traps; the particles and colloids have been removed from water samples by cross-flow ultrafiltration. On the basis of radionuclide inputs and outputs, lake budget calculations have been made for 137Cs and 90Sr during the period of ice-cover. Daily transport of radionuclides is considerably less than that observed during the spring snowmelt period when discharges are high. Size distribution patterns of Cs and Sr observed during winter are compared with previously published data from the same lake during the spring spate. The retention of 137Cs is similar in winter and spring, but retention of 90Sr is greater in winter.

Accidents↗

Radioactive contamination of soils in lower Saxony, Germany, after the Chernobyl accident.

The horizontal and spatial distribution of artificial and natural radionuclides in soils, and the vertical migration velocity of 0.8-2.0 cm per annum for caesium were examined in order to determine whether caesium is still in the root zone of major plants and, therefore, part of the food-chain. The vertical distribution patterns of caesium are dependent on the different physico-chemical soil properties. The soil samples were analysed with a pure Ge detector. In south-eastern Lower Saxony, the maximum gamma-activity for 137Cs of 33.3 kBq m-2 was found in a depth range of 0-20 cm (January 1, 1989). This was correlated with areas that had received heavy rainfall on May 4, 1986. On January 1, 1989 approximately 60% of the Chernobyl caesium was still in the top 0-2 cm of the topsoil.

Accidents↗

Post-Chernobyl accident radioactivity measurements in the Comunidad Autonoma de Valencia, Spain.

Increased atmospheric radioactivity after the accident in Chernobyl was first detected on air filters. Measurements were begun in Valencia on May 2, 1986, with the maximum activity being observed around May 3-4, 1986. As a consequence of this accident, annual campaigns of measurements on migrating birds (several species of aquatic birds and song-thrushes) were started. The data corresponding to the campaign immediately after the accident (1986/87) show a generalized contamination (approximately 50% of the measured specimens). Significant levels of 134Cs, 137Cs and 110Agm were found. It is important to note that 110Agm is only present in Aythya ferina. In the successive campaigns in 1988/89 and 1989/91 few samples were found to be contaminated and only 137Cs was identified. Strontium-90 was measured and identified in some specimens, mainly in their bones.

Accidents↗

Radioactive contamination of food sampled in the areas of the USSR affected by the Chernobyl disaster.

In October 1990 a Netherlands humanitarian fact finding mission on aid to people affected by the Chernobyl disaster visited contaminated regions in Russia, Byelorussia and the Ukraine. The mission consisted of medical, socio-psychological and agricultural experts. The results of radioactivity measurements on food products sampled in the contaminated areas are reported here and the radiation burden for the Soviet citizens due to these products is discussed. The radiocaesium contamination measured in 19 food products ranged between 0 and 170 Bq kg-1 and 40K from 25 to 200 Bq kg-1 in the fresh product. Strontium-90, measured in a few samples, was found to be between 1.8 and 30 Bq kg-1. Mushrooms and reindeer moss were very highly contaminated: from 103,000 to 284,000 Bq kg-1 of radiocaesium in the fresh product. Strontium-90 in these samples was 7.8-1550 Bq kg-1. The contamination of all food products was far below the stated limits, except for mushrooms. Extrapolation of the results to the total food consumption gave the radioactive burden due to this food as an estimated 0.2 mSv per year. All of the food products investigated, except mushrooms, can be regarded as safe with respect to radioactive contamination. In addition to sampling agricultural produce, field exposure measurements were also carried out. The measured values, expressed in equivalent doses, ranged from 1.8 to 14 mSv per year at a height of 1 m, with a median value of about 4 mSv per year.

Accidents↗

Sézary syndrome with a complex, frameshift p53 gene mutation in a Chernobyl survivor.

We report a case of Sézary syndrome in a patient who was in the immediate vicinity of the Chernobyl nuclear reactor accident 18 months prior to presentation. A complex, frameshift p53 gene mutation was subsequently identified in tumour tissue, consisting of an 8-base pair deletion and a T-->G point mutation in exon 7. This is characteristic of damage caused by ionizing radiation, which suggests a causal link between exposure to ionizing radiation and the subsequent development of Sézary syndrome, a rare form of T-cell leukaemia/lymphoma.

Gene Deletion↗

Endocrine and reproductive health status of men who had experienced short-term radiation exposure at Chernobyl.

Hormonal and semen parameters in 416 men aged 25-45 years were examined: 328 were men who cleaned the territory around the Chernobyl nuclear reactor (called 'liquidators') and 88 were healthy age-matched controls. The dose of radiation received by the liquidators was 0.16 +/- 0.08 Gy. LH, FSH, prolactin, testosterone and cortisol levels were assayed using WHO-matched reagents. Semen analyses were performed according to the WHO Manual (1992). The mean concentration of all hormones in liquidators and controls were within the WHO-defined normal range. The mean levels of LH and cortisol in liquidators were significantly lower (p = 0.013 and p < 0.001, respectively) and testosterone significantly higher (p = 0.023) than in controls. The variations in hormone levels in liquidators were not correlated with the acquired doses of radiation as measured by personal dosimeters (film badges). Semen parameters in a subgroup of 70 liquidators were within the normal WHO-defined range. The percentage of normal forms of spermatozoa in liquidators (35.0 +/- 13.1%) was significantly lower (p < 0.015) than in a control group (42.8 +/- 8.9%). The study has shown that exposure of men to relatively short-term radiation did not cause long-lasting disruption of their endocrine status and spermatogenesis. The study was 7-9 years retrospective and it is therefore impossible to infer what the immediate effects of the radiation exposure were on these parameters.

Adult↗

Iodine prophylaxis in the aftermath of the Chernobyl accident in the area of Sejny in north-eastern Poland.

The aim of our study was the estimation of the effects, possible side-effects and immunological reactions after the mass iodine prophylaxis following the Chernobyl nuclear disaster. 1457 subjects, aged 6-55 yrs, filled in our questionnaires and in 1191 of them the titres of antithyroid antibodies (TA) including ATMA--Anti-Human Thyroid Membrane Antibodies and TGAb--Anti-Thyreoglobulin Antibodies were estimated. Our study revealed that the prophylaxis, recommended in Poland only for children and teenagers was widely used (more than 90%) and relatively safe. No serious side effects, especially in pregnant women consuming KI were reported. The frequency and mean titres of TA were similar in adults who took and did not take stable iodine. The incidence of TA could be connected with many different factors including iodine deficiency, endemy of goitre as well as iodine prophylaxis. The reason of this phenomenon may be explained in long-term population studies.

Adolescent↗

Antithyroid autoantibodies in the examined population with iodine prophylaxis after the Chernobyl catastrophe.

The aim of the present study was the observation of the frequency of antithyroid autoantibodies in the population in low endemic goitre area after mass iodine prophylaxis after the Chernobyl catastrophe and the estimation of TSH and thyroid hormones secretion in this population. On the basis of the investigations carried out we could conclude that the frequency of antithyroid autoantibodies in the population with confirmed endemic goitre is comparable to the frequency of antithyroid autoantibodies in the healthy population. ATA occurrence in children after iodine prophylaxis could confirm the hypothesis that thyroglobulin immunity is higher after iodine intake. The lower T3 concentration observed in the group with antithyroid autoantibodies suggests that autoantibodies may be involved in the thyroid hormones synthesis or peripheral conversion of thyroid hormones.

Accidents, Occupational↗

[Exposure to radioactivity in the perinatal period following the reactor accident in Chernobyl].

After the Chernobyl nuclear accident on 26 April 1986 Europe experienced increased radioactive radiation by contamination of the atmospheric aerosol and the soil. Foods emanating radioactive radiation were ingested by the population to an increased extent via the food chain. This proportion of radioactive radiation accounted for about 80% of the total irradiation exposure and prompted us to examine mother's milk, amniotic fluid and placenta of newborn in respect of their concentrations of radionuclides I-131, Cs-134 and Cs-137. Due to the short half-life of I-131 an increased concentration of this substance was seen only during the first eight weeks after the nuclear accident. On the other hand, however, there was a clear increase in Cs-134 and Cs-137 from this time onward, the highest concentration of these two nuclides being measured only after one year after the accident. Despite the enhanced exposure to radioactivity of mother's milk and amniotic fluid, the guideline values laid down by Federal German legislation were not exceeded.

Accidents↗

[Long-term radiation damage to the skin and eye after combined beta- and gamma- radiation exposure during the reactor accident in Chernobyl].

BACKGROUND: In April 1986, numerous reactor workers and firemen were exposed to high doses of ionizing radiation during the Chernobyl nuclear power plant accident. Apart from high ambient gamma-ray exposures they received inhomogeneous contamination with beta-rays from fission products, resulting in severe skin exposure. PATIENTS AND METHODS: Sixteen of these so called Liquidators were repeatedly examined between 1991 and 1996. Their doses ranged from 0.35 to 9 Gy, partly confirmed by determination of chromosomal aberrations. Ophthalmologic examination included non-subjective assessment of lenticular radiation damage with an electronic Scheimpflug camera system. Digital image analysis allowed the comparison of opacification units to previous and normal findings. RESULTS: Four Liquidators had posterior subcapsular opacifications in different degrees, one presented only after cataract extraction. One patient had dense corticonuclear cataracts and pseudoexfoliation-like changes. Three men had severe dry eye syndrome. Eight men had no ocular complications. Retinal radiation damages were absent. 15 Liquidators suffered from severe chronic cutaneous radiation damage, which led to amputations in 3 cases. CONCLUSIONS: A relation between ocular and dermatological findings was not expected and could, in fact, not be seen. The comparison of posterior subcapsular opacification and doses revealed no distinct relation, although it indicates a correlation that is here not quantified. The doses represent organ doses for the bone marrow which is primarily exposed to deeper penetrating gamma-radiation. Thus they need not be correlated with combined beta- and gamma-doses in organs such as skin and eye because the superficial exposure due to beta-radiation may differ greatly form the whole body exposure as reflected in bone marrow doses.

Accidents, Occupational↗

[Iodine 131: biokinetics, radiation exposure and risk assessment with reference to the reactor accident at Chernobyl].

Following the reactor accident at Chernobyl, this paper describes the biokinetics of radioiodine in man and discusses the radiation exposure resulting from intake of 131I. The risk of radiation-induced thyroid carcinomas and of congenital abnormalities is evaluated. Assuming a linear dose/risk relationship, one can calculate an increase in mortality from thyroid carcinomas amongst children in southern Germany of 100 to 101 per million children. For adults in southern Germany, and for the rest of the population in Germany, the figure is considerably lower. Gonadal dose from the 131I released is so small, compared with the annual natural radiation exposure, that it is not appropriate to discuss genetic effects.

Accidents↗

Bone marrow transplantation after the Chernobyl nuclear accident.

On April 26, 1986, an accident at the Chernobyl nuclear power station in the Soviet Union exposed about 200 people to large doses of total-body radiation. Thirteen persons exposed to estimated total-body doses of 5.6 to 13.4 Gy received bone marrow transplants. Two transplant recipients, who received estimated doses of radiation of 5.6 and 8.7 Gy, are alive more than three years after the accident. The others died of various causes, including burns (the cause of death in five), interstitial pneumonitis (three), graft-versus-host disease (two), and acute renal failure and adult respiratory distress syndrome (one). There was hematopoietic (granulocytic) recovery in nine transplant recipients who could be evaluated, six of whom had transient partial engraftment before the recovery of their own marrow. Graft-versus-host disease was diagnosed clinically in four persons and suspected in two others. Although the recovery of endogenous hematopoiesis may occur after exposure to radiation doses of 5.6 to 13.4 Gy, we do not know whether it is more likely after the transient engraftment of transplanted stem cells. Because large doses of radiation affect multiple systems, bone marrow recovery does not necessarily ensure survival. Furthermore, the risk of graft-versus-host disease must be considered when the benefits of this treatment are being weighed.

Accidents↗

Delayed effects of accidental cutaneous radiation exposure: fifteen years of follow-up after the Chernobyl accident.

BACKGROUND: During the Chernobyl accident in 1986, 237 individuals were identified as having the most severe exposure to ionizing radiation. In the period between 1998 and 2000, 99 long term survivors out of this group were reassessed for radiation-induced cutaneous lesions. OBJECTIVE: To identify sequelae of accidental cutaneous irradiation. METHODS: Detailed dermatologic examinations, including biopsies of suspicious cutaneous lesions for histopathologic examination and 20 MHz sonography, were performed in all patients. RESULTS: Twenty-two of the 99 patients displayed radiation-induced cutaneous lesions. Epidermal atrophy, telangiectases, and pigment alterations were present in all these individuals. Keratotic lesions were found in 14 patients. Cutaneous fibrosis was documented in 8 individuals by the use of 20 MHz sonography, while a radiation ulcer was found in 5. In one patient, two basal cell carcinomas were found. CONCLUSION: The life-long follow-up of irradiated persons is of great importance in order to identify cutaneous neoplasms at an early treatable stage.

Cohort Studies↗

"Rogue" lymphocytes among Ukrainians not exposed to radioactive fall-out from the Chernobyl accident: the possible role of this phenomenon in oncogenesis, teratogenesis, and mutagenesis.

Cultured lymphocytes exhibiting extreme cytogenetic damage (rogue cells) were observed in preparations from 8 of 24 individuals sampled in Krasilovka, a Ukrainian village receiving little or no increased radiation after the Chernobyl disaster, but were not observed in an additional 24 persons from two Russian towns in the more contaminated area. This observation cements the worldwide occurrence of these cells. The present data plus a review of the literature establish that rogue cells appear in brief bursts simultaneously in certain individuals of discrete populations. We suggest that the pattern is consistent with the action of a viral trigger that acts directly or indirectly--the latter possibly through the activation of latent chromosomal retroposons. If this phenomenon occurs in other tissues, it may have important implications for oncogenesis, teratogenesis, mutagenesis, and evolution.

Accidents↗

Fallout from the Chernobyl nuclear disaster and congenital malformations in Europe.

Investigators estimate that the population exposure that resulted from the Chernobyl fallout is in the range of natural background radiation for most European countries. Given current radiobiologic knowledge, health effects-if any-would not be measurable with epidemiologic tools. In several independent reports, however, researchers have described isolated peaks in the prevalence of congenital malformations in the cohort conceived immediately after onset of the fallout. The consistency of the time pattern and the specific types of malformation raise concern about their significance. In this study, the author summarizes findings from Turkey, Belarus, Croatia, Finland, Germany, and other countries, and implications for radiation protection and public health issues are discussed.

Abnormalities, Radiation-Induced↗

Dietary and clastogenic factors in children who immigrated to Israel from regions contaminated by the Chernobyl accident.

The authors evaluated the possible association between dietary history and plasma clastogenic factors in children who immigrated to Israel between 1989 and 1993 from regions contaminated by the Chernobyl accident. The authors compared questionnaire data about demographic variables, dietary histories before and after immigration occurred, and health status with clastogenic factor scores for 162 immigrants. Logistic regression analysis revealed a negative association between clastogenic factor scores and frequency of consumption of fresh vegetables and fruit among children < or = 7 yr of age during the postimmigration period. Intake of eggs and fish by boys who were < or = 7 yr of age prior to immigration was associated positively with clastogenic factor scores. Consumption of fresh vegetables and fruits afforded protection to the immune systems of children who were < or = 7 yr of age.

Adolescent↗