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The Chernobyl fallout in Salzburg/Austria and its effect on blood chromosomes.

The radioactive fallout of the Chernobyl accident caused an increase in radiation dose of 20 to 110 per cent over the normal environmental burden to the inhabitans of Salzburg City in Austria (in a distance of about 1300 km from the accident). The structural chromosome aberration in the lymphocytes of the peripheral blood of 15 test-persons have been investigated one year after the accident. From two of these we know also the aberration frequencies before the accident which were significantly lower. The results from all test persons were pooled according to their Cs137 and Cs134 content, measured by whole body counter. Their mean additional blood doses from the incorporated caesium plus the external fallout radiation were 0.23, 0.36 and 0.55 mGy/yr. The aberration frequencies increased with dose. The slope of the best straight-line through the points was 2.0 +/- 0.7 total chromosome type aberrations in 100 metaphases per mGy/yr. This result fits in well with former investigations of persons with individually calculated radiation burden from the environment. The sharp increase with dose at this low level is not compatible with values extrapolated from high doses. The usual dose assessment based on chromosome aberrations extrapolated from high to low doses is therefore not possible in the range considered in this investigation.

Accidents↗

[Radio-ecological and hygienic assessment of consequences of forest fires in the areas polluted during the Chernobyl accident].

Retransfer of radionuclides on the condensation trails of Chernobyl radioactive fallouts during forest fires has been experimentally evaluated and their mathematical transfer model verified. It has been shown that radionuclide retransfer will make no great impact on additional pollution of an area even under the most unfavourable conditions. The contribution of convective and non-convective components of transfer to the formation of a radioactive aerosol concentration field has been assessed. Time course of changes in the concentration of radioactive aerosol and its dispersive composition are shown in different phases of fire and at different distance from its source.

Aerosols↗

An approach to detecting delayed effects of radioactive contamination on industrial-urban-area dwellers.

Detecting changes in humans that result from radioactive contamination of the area of residence many years after an incident (i.e., when the radiation has substantially decayed) presents a difficult epidemiological problem. Problems of this kind are even more complicated ina areas where the population is continually exposed to other harmful man-made factors. The city of Kamensk-Uralsky (Sverdlovsk region, Russia) is a good case in point. In 1957, part of Kamensk-Uralsky was contaminated as the result of an accident at the Kyshtym nuclear plant. In addition, the population of the contaminated area is being exposed to atmospheric emissions from several industrial enterprises. Two comparable groups of residents were formed: one in the contaminated are and another in a control area within the same city characterized by similar levels of chemical pollution but substantially lower radioactive contamination. The groups were composed of only those people who had been living in these areas continually since time of the accident and who were under 15 years of age at the time of the accident. The groups were matched by sex, age, and socio-occupational characteristics. For each subject, data were gathered on more than 50 parameters including hematological, immunological, and biochemical indices of the health status. All these data were obtained from blood tests taken in the fall of 1992. Data processing was carried out with the help of a computerized mathematical pattern recognition methodology, which ensured reliable discrimination between the generalized health status in the areas under study. We found that the health status of inhabitants of the area more contaminated with radioactive fallouts was adversely affected by radiation.

Adult↗

Lake fish as the main contributor of internal dose to lakeshore residents in the Chernobyl contaminated area.

Two field expeditions in 1996 studied 137Cs intake patterns and its content in the bodies of adult residents from the village Kozhany in the Bryansk region, Russia, located on the shore of a drainless peat lake in an area subjected to significant radioactive contamination after the 1986 Chernobyl accident. The 137Cs contents in lake water and fish were two orders of magnitude greater than in local rivers and flow-through lakes, 10 years after Chernobyl radioactive contamination, and remain stable. The 137Cs content in lake fish and a mixture of forest mushrooms was between approximately 10-20 kBq/kg, which exceeded the temporary Russian permissible levels for these products by a factor of 20-40. Consumption of lake fish gave the main contribution to internal doses (40-50%) for Kozhany village inhabitants Simple countermeasures, such as Prussian blue doses for dairy cows and pre-boiling mushrooms and fish before cooking, halved the 137Cs internal dose to inhabitants, even 10 years after the radioactive fallout.

Agaricales↗

15 years after Chernobyl: new evidence of thyroid cancer.

The Chernobyl nuclear power plant accident happened on April 26, 1986. We investigated the cause of the striking increase in frequency of thyroid cancer in children who lived within a 150 km radius of Chernobyl and who were born before and after the accident. No thyroid cancer was seen in 9472 children born in 1987-89, whereas one and 31 thyroid cancers were recorded in 2409 children born April 27, 1986, to Dec 31, 1986, and 9720 born Jan 1, 1983, to April 26, 1986, respectively. Short-lived radioactive fallout caused by the Chernobyl accident probably induced thyroid cancer in children living near Chernobyl.

Adolescent↗

Thyroid abnormalities among children in the contaminated area related to the Chernobyl accident.

Gradual increases of various radiation-related diseases including thyroid cancer following the Chernobyl accident have been recently reported. We have carried out systematic thyroid surveys in school children aged 10-15 years in the highly contaminated area and compared the results with a similar survey in a nonaffected neighboring area as a control. Systematic examinations of the thyroid gland were performed in 888 schoolchildren (408 males and 480 females) in the districts of Chechelsk city with 5 to over 40 Ci/km2 of radiation level for 137Cs. In the control area (Bobruisk city), 521 children with the same age range (229 males and 292 females) were examined. Thyroid surveys were carried out as follows: palpation, ultrasonography, blood examinations of thyroid function, and measurements of daily urinary excretion of iodine. Certain thyroid abnormalities were observed in the high radioactive fallout area more frequently than in the control region. In particular, the prevalence of multiple micronodular lesions in diffuse goiter in the contaminated area was significantly higher than in the control area. However, endemic goiter due to iodine deficiency was present in both districts. The environment factor of iodine deficiency might have resulted in the early occurrence of ultrasonographic thyroid abnormalities attributed to radioactive contamination.

Adolescent↗

Aquatic mosses as a monitoring tool for 137Cs contamination in streams and rivers-a field study from central southern Norway.

Mosses are frequently used as biomonitors for trace element pollution in the aquatic environment. The purpose of this study was to assess their usefulness as a tool in monitoring and in regional surveys of radioactive contamination. Specimens of the aquatic mosses, Fontinalis antipyretica and F. dalecarlica, were transplanted from non-contaminated areas to streams and rivers in the Norwegian Jotunheimen Mountains and neighbouring lowland areas that had received radioactive fallout after the Chernobyl accident. Equilibrium concentrations of 137Cs in the exposed mosses were reached after a few weeks. Two series from 20 streams in 1994 and 1996 show linear correlations between activities in water and moss samples and biomagnification ratios of 10(4) - 10(5). We conclude that mosses are better suited for monitoring purposes than water samples, because they provide values integrated over weeks while the radioactivity in surface waters can be subject to rapid variations according to hydrological events. The activity concentrations in aquatic mosses can be easily measured with good precision even when aqueous concentrations are below the limit of detection. Use of aquatic mosses also reduces the logistic problems of transporting large volumes of water, especially in areas inaccessible by road.

Bryopsida↗

Chernobyl-related thyroid cancer: what evidence for role of short-lived iodines?

Over 500 cases of thyroid cancer were diagnosed in Belarus between 1986 and 1995 among persons exposed as children (under 15 years of age) to radioactive contamination from the Chernobyl nuclear accident. There is little doubt that radioactive iodine isotopes emitted during the nuclear explosion and subsequent fire were instrumental in causing malignancy in this particular organ. Comparison of the observed geographic distribution of Chernobyl-associated thyroid cancer incidence rates by districts with contamination maps of radioactive fallout shows a better fit for estimated 131I contamination than for 137Cs. Because 131I used for medical purposes had not been considered carcinogenic in humans in the past, and in view of the unusually short latency period between exposure and clinical manifestation of cancer, it is suspected that not only 131I but also energy-rich shorter-lived radioiodines may have played a role in post-Chernobyl thyroid carcinogenesis. Measurements of iodine isotopes are not available, but reconstruction of geographic distributions and estimations of radioactive fallout based on meteorological observations immediately following the accident could provide a basis for comparison with the distribution of thyroid cancer cases. In this paper, data from the Epidemiological Cancer Register for Belarus will be used to show geographic and time trends of thyroid cancer incidence rates in the period from 1986 to 1995 among persons who were exposed as children, and these will be compared with the estimated contamination by radioiodines. Tentative conclusions are drawn from the available evidence and further research requirements discussed.

Adolescent↗

POSEIDON/RODOS models for radiological assessment of marine environment after accidental releases: application to coastal areas of the Baltic, Black and North Seas.

In the framework of the developments of the European system RODOS (Real-time On-line DecisiOn support System) for emergency response to nuclear accident, the computer code POSEIDON, that was developed to assess the radiological consequences of radioactive releases into marine environment, was adapted to cope with emergency conditions, in situations of radioactive discharges into the oceans from direct deposition from the atmosphere, sunken ships and containers, from discharges of rivers and estuaries and from coastal run-off. Based on the box model developed within the 'Marina' project, POSEIDON can calculate the dose effects from radionuclide releases in the coastal waters of Europe integrated over long time periods. A dynamic food chain model was implemented to deal with the short-term dynamical uptake of radioactivity by specific marine plants and organisms. POSEIDON has been installed on a UNIX platform to be fully compatible with RODOS input/output databases and on a Windows platform with an interface based on web technology. The 3D hydrodynamic model THREETOX is a part of the POSEIDON/RODOS system. It has been applied to coastal areas of the Baltic Sea, the Black Sea, and the North Sea. to derive the parameters for a flexible system of well-defined model compartments to be adapted to emergency conditions. The activity concentrations in water and in the marine food web were calculated by means of POSEIDON for radioactive fallout resulting from bomb testing, from the Chernobyl accident, and from routine discharges from nuclear facilities. POSEIDON's model results were compared with measurement data, and with calculation results from THREETOX. The model results agreed with the measurement data sufficiently.

Animals↗

Use of a satellite-derived land cover map to estimate transport of radiocaesium to surface waters.

During the weeks to months after the deposition of radioactive fallout, the initial concentration of radioactivity in rivers and lakes declines as a result of flushing and removal to bottom sediments. In the long-term, however, radioactivity in the water body can remain at significant levels as a result of secondary contamination processes. In particular, it is known that soils contaminated by long-lived radionuclides such as 137Cs and 90Sr provide a significant source to surface waters over a period of years after fallout. Using The Land Cover Map of Great Britain, a satellite-derived land cover map as a surrogate indicator of soil type, we have related catchment land cover type to long-term 137Cs activity concentrations in 27 lakes in Cumbria, UK. The study has shown that satellite-derived maps could be used to indicate areas vulnerable to high long-term 137Cs transport to surface waters in the event of a nuclear accident. In these Cumbrian lakes, it appears that residual 137Cs levels are determined by transfers of 137Cs from contaminated catchments rather than within-lake processes. Only three of the cover types, open shrub moor, bog and dense shrub moor, as identified by the satellite, are needed to explain over 90% of the variation in long-term 137Cs activity concentrations in the lakes, and these have been shown to correlate spatially with occurrence of organic soils.

Cesium Radioisotopes↗

Kinetics of dissolution of Chernobyl fuel particles in soil in natural conditions.

Kinetic of fuel particles dissolution under natural environmental conditions has been investigated using the data on (90)Sr speciation in soils collected from 1995 to 1997 within the Chernobyl nuclear power plant 50 km zone. The dependency of fuel particles dissolution constants on the soil acidity (pH = 4-7) has been obtained on the basis of large and statistically reliable experimental data. Results show that between 2 and 21% of (90)Sr activity is associated with weathering resistant fuel particles. Therefore, these particles would not influence the radiological situation in the near future. The map of the main agrochemical characteristics and the map of the fuel particles dissolution constants have been created for the 30-km zone territory. According to the prognosis of dynamics of fuel particles dissolution in the investigated zone, a radiological situation along the fuel paths of radioactive fallout in present time reached a stable state. An increasing in absolute contents of (90)Sr mobile forms in neutral soils will be observed in the next 10-20 yr. However, the difference between the maximum level of mobile forms contents and their existing contents will not exceed 20%.

Kinetics↗

First responders and nuclear terrorist attacks.

Avoidance of downwind radioactive fallout exposure within the first few hours after a nuclear or radiological dispersal device detonation can save lives and minimize radiation exposure. First responders with awareness training can help to avoid prompt fatalities and excessive contamination or exposure following such a detonation. This paper outlines some of the critical components of the situational awareness and actions necessary to save lives and minimize radiation contamination and exposure.

Disaster Planning↗

Governmental responsibility for victims of atomic testing: a chronicle of the politics of compensation.

Since 1945 the U.S. government has conducted extensive atomic testing for purposes of protecting the national security and developing industrial uses of nuclear power. Newly available information indicates that many citizens were unwittingly harmed by exposure to radioactive fallout from this testing. The victims are pressuring the government to accept liability for its actions and offer compensation for the damages. To date, however, their efforts have been largely unsuccessful. This article analyzes the politics of the atomic compensation movement, from its beginnings through the 97th Congress. It concludes that, barring the enactment of specific legislation, atomic victims stand little chance of gaining financial compensation or moral satisfaction.

Disability Evaluation↗

Infant leukaemia after in utero exposure to radiation from Chernobyl.

There has been no documented increase in childhood leukaemia following the Chernobyl accident. However, different forms of childhood leukaemia may not be equally susceptible to radiation carcinogenesis. Infant leukaemia is a distinct form associated with a specific genetic abnormality. Outside the former Soviet Union, contamination resulting from the Chernobyl accident has been highest in Greece and Austria and high also in the Scandinavian countries. All childhood leukaemia cases diagnosed throughout Greece since 1 January 1980 have been recorded. Here we report that infants exposed in utero to ionizing radiation from the Chernobyl accident had 2.6 times the incidence of leukaemia compared to unexposed children (95% confidence interval, 1.4 to 5.1; P approximately 0.003), and those born to mothers residing in regions with high radioactive fallout were at higher risk of developing infant leukaemia. No significant difference in leukaemia incidence was found among children aged 12 to 47 months. Preconceptional irradiation had no demonstrable effect on leukaemia risk at any of the studied age groups.

Adolescent↗

Histological changes in Pinus sylvestris L. in the proximal-zone around the Chernobyl power plant.

In September 1990, samples of wood and bark were collected from Pinus sylvestris L. at three locations exposed to different levels of radioactive fallout from the 1986 accident at the Chemobyl nuclear power plant (NPP). Cross-sections of wood from the most exposed location showed a distinct change in histology in the annual ring of 1986, a consequence of the accident on 26 April. The width of annual rings decreased after the accident, and the relative width of latewood in annual rings increased transiently in 1986 and subsequently decreased in 1987. In 1987, an increase in the number of vertical resin ducts was observed, related to contamination at the location, and the number of radial rays decreased at the two locations of higher contamination. The radionuclide content in the bark was found to correlate with the degree of damage in the wood. There are several hypotheses about the contribution from various types of radioactive contamination, but the results indicate that both 'cloud gamma' and deposited radioactivity (beta and gamma) were of importance. The present work suggests that detailed studies of dose-effect relationships after exposure to different dose rates and radiation qualities may establish the usefulness of pine trees as in situ, time-recording differential dosimeters of ionizing radiation.

Gamma Rays↗

Immunomodulatory and clinical effects of Viscum album (Iscador M and Iscador P) in children with recurrent respiratory infections as a result of the Chernobyl nuclear accident.

Ninety-two children 5 to 14 years of age living in areas exposed to the radioactive fallout from Chernobyl with recurrent respiratory infections (RRIs) were treated after randomization with either Viscum album praeparatum mali or pini (Iscador M or P). The dosage was two subcutaneous injections a week for 5 weeks with individual doses of 0.001 mg to 1.0 mg. Both Viscum album preparations were effective in significantly reducing clinical symptoms. One year after a single treatment course, the frequency of RRI relapses decreased by 78% and 73%, respectively. Immunomodulatory effects were assessed by investigation of lymphocyte subsets, natural killer (NK) cell activity, phagocytic and oxidative activity of polymorphonuclear leukocytes, and antiviral activity of serum before and 1 week after treatment. Viscum album therapy resulted in normalization of initial immune indices either below or above the normal ranges. High levels of antiviral activity before treatment were significantly decreased by Viscum album mali. Viscum album treatment should be studied further in children with RRI.

Adolescent↗

Thyroid cancer following exposure to radioactive iodine.

The thyroid gland is one of the most sensitive organs for radiation-induced oncogenesis and the magnitude of the risk from external radiation is well understood. This is not the case for internal radiation derived from the radioiodines, a matter of practical importance because of medical use and potential accidental exposure. This article reviews current knowledge derived from the follow-up of patients receiving diagnostic or therapeutic 131I and populations exposed to radioactive fallout. The latter includes the nuclear power station accident at Chernobyl and the results of atomic bomb development and testing at Hanford, the Nevada Test Site and the Marshall Islands. The most cogent information comes from Chernobyl where an epidemic of childhood thyroid cancer has followed exposure to radioiodine that was mainly 131I. Although much has been learned from this experience about the nature of radioiodine induced thyroid cancer in young children, the reconstruction of thyroid radiation doses is too preliminary to provide accurate knowledge of the risk in comparison to that from external radiation. In the Marshall Islands, much of the exposure was from short-lived radioiodines as well as external radiation, obviating the possibility to determine the risk from 131I. Exposure to 131I in the continental United States from atomic bomb testing is expected to have caused some thyroid cancers, but only in the immediate vicinity of the Nevada Test Site has any evidence of radiation-induced thyroid neoplasms been adduced. This evidence is minimally significant statistically, and not significant for thyroid cancer per se. Medical use of radioiodine has not been observed to cause thyroid cancer but very few of the patients studied were young children, the group most sensitive to thyroid radiation. Despite these limitations, this information is sufficient to make some suggestions concerning protective measures in the case of nuclear accidents and the follow up of individuals who have been exposed.

Humans↗

[Radiation-induced thyroid carcinomas in children: high prevalence of RET rearrangement].

Papillary thyroid carcinomas were observed in children living in the Gomel region of Belarus at the time of the Chernobyl reactor accident in April 1986. Radioactive fallout, iodine-131 in particular, led to thyroid doses of > 10 Gy in some cases. Till now, more than 400 thyroid carcinomas developed. They provide a unique possibility to search for characteristic molecular aberrations. Small fresh frozen thyroid tumor samples from 59 children were available. cDNA after reverse transcription of mRNA was amplified by multiplex PCR and analyzed for the presence of RET rearrangement (PTC1, 2 or 3) by identification-PCR with specific primers and by direct sequencing. A significantly higher prevalence of RET rearrangement was found in the thyroid carcinomas of radiation-exposed children than formerly described for adult thyroid carcinomas. While the prevailing type of RET rearrangement in adult thyroid carcinomas is PTC1 involving RET and the H4 gene, the majority of tumors in radiation-exposed children shows PTC3. In this type of rearrangement the 3'-tyrosin kinase domain of RET becomes dependent on the 5'-regulatory part of the ELE gene. Different breakpoints were found in the ELE gene. Besides ELE/RET transcripts, reciprocal RET/ELE transcripts were expressed indicating a complete inversion of the two genes after double stand break and their functional activity in both rearranged forms. Paracentric inversion on chromosome 10 bringing the functional tyrosine kinase domain of c-RET under the regulatory control of the ubiquitously expressed ELE gene appears to be a typical molecular lesion in thyroid carcinomas of children after radiation. This rearrangement is thought to endow juvenile thyrocytes with a clonal growth advantage and may be a critical initiating event of thyroid carcinogenesis in radiation-exposed children.

Adult↗