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137Cs concentration in meat of wild boars (Sus scrofa) in Croatia a decade and half after the Chernobyl accident.

Gamma-spectrometric measurements of 137Cs activities in meat of wild boars collected in Croatia at several locations with different levels of 137Cs contamination are presented. Samples were collected during the period between 2000 and 2002, about 15 years after the Chernobyl accident. 137Cs concentrations ranged over three orders of magnitude: 0.4-611.5 Bq kg(-1). On the basis of these results, 137Cs concentrations at researched areas could be categorized into three groups: (i) the area of Slavonski Brod, Lipik and Slunj with 137Cs concentrations in meat of only a few Bq kg(-1); (ii) the area of Vrbovsko and Sirac with 137Cs concentrations of a few tens of Bq kg(-1); and (iii) the Fuzine area with 137Cs values in wild boar meat of a few hundreds of Bq kg(-1). In areas with approximately equal contamination level, 137Cs concentrations in wild boar meat varied over two orders of magnitude. This fact suggests that the main reason for high 137Cs values in wild boar meat could be due to food consumed by wild boars, and only secondarily in contamination level of area where they live. Intensive mushroom consumption during autumn months could be one of the factors responsible for high 137Cs values in wild boar meat. An average dose arising from 137Cs due to ingestion of wild boar meat in Croatia is below radiological health concern except in the area of Fuzine, and only in cases of high annual wild boar meat intake, probably by hunters or members of their families.

Agaricales↗

Indications of limited altered gene expression in Pinus sylvestris trees from the Chernobyl region.

To evaluate the consequences of irradiation on the vegetation of the Chernobyl region, gene expression was compared in morphologically normal and dwarf needles from the same Pinus sylvestris trees in a region where the absorbed dose was 3-5 Gy. To compare the levels of gene expression, arrays consisting of 373 Pinus taeda cDNAs were hybridized with labeled cDNA derived from normal and dwarf needles of P. sylvestris. Twelve genes were significantly (P<0.01) up- or down-regulated between normal and dwarf needles for all five trees taken together. Five of these, related to stress or development, were up- or down-regulated 1.25-1.7-fold in the dwarf needles. There were no significant differences in (137)Cs content in the normal and dwarf needles, or in elongation growth rate of seedlings raised under controlled conditions from seed derived from trees in the region that had received a radiation dose over the range 2-12 Gy.

Cesium Radioisotopes↗

Cesium-137 in grass from Chernobyl fallout.

Grass ecosystem was monitored for 137Cs, a relatively long-lived radionuclide, for about 16 years since the Chernobyl reactor accident occurred on April 26, 1986. Cesium-137 in grass gramineae or poaceae the species, ranged from 122.9 Bq kg(-1) (September 4, 1986) to 5.8 mBq kg(-1) (October 16, 2001) that is a range of five orders of magnitude. It was observed that there was a trend of decreasing 137Cs with time reflecting a removal half-time of 40 months (3 1/3 years), which is the ecological half-life, T(ec) of 137Cs in grassland.

Animals↗

Chernobyl radioactivity persists in reindeer.

Transfer of 137Cs in the soil-plant/lichen-reindeer food chain was studied in central (Østre Namdal) and southern Norway (Vågå) during 2000-2003. Reindeer from these areas have been continuously subjected to countermeasure application since the 1986 Chernobyl accident. In both areas no decline in 137Cs concentrations was detectable in reindeer slaughtered in autumn since 1995, or in reindeer slaughtered in winter since 1998-1999. Seasonal differences in 137Cs concentrations in reindeer have been less pronounced in recent years, with 137Cs concentrations occasionally higher in autumn than in winter. Soil-to-plant 137Cs transfer was significantly higher in Østre Namdal than in Vågå. Climatic influences on lichen growth and abundance, and on soil properties that influence the availability of 137Cs for plant uptake, are hypothesized to have a larger impact on long-term transfer of radiocaesium in the soil-plant/lichen-reindeer food chain than has been previously observed.

Animals↗

Resuspension and redistribution of radionuclides during grassland and forest fires in the Chernobyl exclusion zone: part II. Modeling the transport process.

To predict parameters of radionuclide resuspension, transport and deposition during forest and grassland fires, several model modules were developed and adapted. Experimental data of controlled burning of prepared experimental plots in the Chernobyl exclusion zone have been used to evaluate the prognostic power of the models. The predicted trajectories and elevations of the plume match with those visually observed during the fire experiments in the grassland and forest sites. Experimentally determined parameters could be successfully used for the calculation of the initial plume parameters which provide the tools for the description of various fire scenarios and enable prognostic calculations. In summary, the model predicts a release of some per thousand from the radionuclide inventory of the fuel material by the grassland fires. During the forest fire, up to 4% of (137)Cs and (90)Sr and up to 1% of the Pu isotopes can be released from the forest litter according to the model calculations. However, these results depend on the parameters of the fire events. In general, the modeling results are in good accordance with the experimental data. Therefore, the considered models were successfully validated and can be recommended for the assessment of the resuspension and redistribution of radionuclides during grassland and forest fires in contaminated territories.

Animals↗

"Blind" testing of models for predicting the 90Sr activity concentration in river systems using post-Chernobyl monitoring data.

Two different models for predicting the time-dependent mobility of (90)Sr in river systems have been evaluated using post-Chernobyl monitoring data for five large Belarusian rivers (Dnieper, Pripyat, Sozh, Besed and Iput) in the period between 1990 and 2004. The results of model predictions are shown to be in good agreement (within a factor of 5) with the measurements of (90)Sr activity concentration in river waters over a long period of time after the accident. This verifies the relatively good accuracy of the generalised input parameters of these models which were derived primarily from measurements of (90)Sr deposited after atmospheric nuclear weapons testing (NWT). For the cases studied here, the simpler AQUASCOPE model performed just as well as the more complex "Global" model which used GIS-based catchment data as an input. The reasons for this are discussed. Exponential decay equations were also curve-fitted to the data for each river to help assess the uncertainties in the predictive models.

Chernobyl Nuclear Accident↗

Analysis of radiocaesium in the Lebanese soil one decade after the Chernobyl accident.

Fallout from the Chernobyl reactor accident due to the transport of a radioactive cloud over Lebanon in the beginning of May 1986 was studied 12 years after the accident for determining the level of (137)Cs concentration in soil. Gamma spectroscopy measurements were performed by using coaxial high sensitivity HPGe detectors. More than 90 soil samples were collected from points uniformly distributed throughout the land of Lebanon in order to evaluate their radioactivity. The data obtained showed a relatively high (137)Cs activity per surface area contamination, up to 6545Bqm(-2) in the top soil layer 0-3cm. The average activity of (137)Cs in the top soil layer 0-3cm in depth was 59.7Bqkg(-1) dry soil ranging from 15 to 119Bqkg(-1) dry soil. The horizontal variability was found to be about 45% between the sampling sites. The depth distribution of total (137)Cs activity in soil showed an exponential decrease. Estimation of the annual effective dose due to external radiation from (137)Cs contaminated soil for selected sites gave values ranging from 19.3 to 91.6 micro Svy(-1).

Cesium↗

Histopathologic verification of acute leukemia (AL) in a cohort of 463 post-Chernobyl patients from Belarus, Russia and Ukraine.

Seven morphologists examined 382 slide and 82 non-slide, post-Chernobyl pediatric acute leukemia (AL) cases in radiation-exposed areas of Belarus, Russia and Ukraine; part of a case-control study by the International Consortium for Research on the Health Effects of Radiation. Among the slide cases, 99% were confirmed as AL: 92% acute lymphoid leukemia (ALL) and 86% acute myeloid leukemia (AMD demonstrating the utility of FAB classification for distinguishing ALL and AML. Among the non-slide cases, 79% were confirmed as AL: 84% ALL, and 71% AML. This study affirms AL diagnostic accuracy during a time of social upheaval in the former Soviet Union.

Acute Disease↗

DNA damage evaluated by the comet assay in lymphocytes of children with 137Cs internal contamination caused by the Chernobyl accident.

The comet assay is one of the most versatile and popular tools for evaluating DNA damage. Its sensitivity to low dose radiation has been tested in vitro, but there are limited data showing its application and sensitivity in chronic exposure situations. The influence of the internal contamination caused by the Chernobyl accident on the level of DNA damage was evaluated by the comet assay on lymphocytes of 56 Ukrainian children. The study was performed during 2003 on children with demonstrable 137Cs internal contamination caused by food consumption. The children were selected for the study immediately after a 137Cs whole body counter measurement of internal contamination. The minimal detectable amount of 137Cs was 75 Bq. The control group included 29 children without detectable internal contamination, while in the exposed group 27 children with measured activity between 80 and 4037 Bq and committed effective dose between 54 and 3155 microSv were included. Blood samples were taken by a finger prick. The alkaline version of the comet assay was used, in combination with silver stained comets and arbitrary units (AU), for comet measurement. Factors such as disease, medical treatment, surface contamination of children's living location, etc., were considered in the study. Non-significant differences (p > 0.05) in DNA damage in control (9.0 +/- 5.7 AU) versus exposed (8.5 +/- 4.8 AU) groups were found. These results suggest that low doses of 137Cs internal contamination are not able to produce detectable DNA damage under the conditions used for the comet assay in this study. Further studies considering effects of high exposure should be performed on chronically exposed people using this assay.

Adolescent↗

Microsatellite mutations show no increases in the children of the Chernobyl liquidators.

We performed a study on Belarusian "liquidators", exploring whether increase in the frequencies of germline mutations at microsatellite loci could be found in their progeny. The liquidators, mostly young males, were those involved (during 1986 and 1987) in clean-up operations in the radioactively contaminated area following the Chernobyl nuclear power plant accident in 1986. Many liquidators fathered children during the clean-up period and after the work had been terminated. The numbers of families studied were 64 (liquidators) and 66 (controls). A total of 72 loci (31 autosomal, one X-linked and 40 Y-linked) were used. DNA was isolated from peripheral blood lymphocytes and the microsatellite loci were amplified by the polymerase chain reaction with fluorescence-labelled primers. Mutations were detected as variations in the length of the loci. At the Y-linked loci, the mutation rates (expressed as number of mutations among the total number of loci for the individuals included) are 2.9 x 10(-3) (4/1392) and 2.1 x 10(-3) (3/1458) in the children of exposed and control parents, respectively. This difference is not statistically significant. At the autosomal loci, the corresponding estimates are 5.9 x 10(-3) (11/1862; exposed group) and 8.5 x 10(-3) (18/2108; control). Again, the difference is not significant. The possibility that the Belarusian population might have been unexpectedly exposed to some chemical contaminants in the environment appears unlikely in view of the finding that the spontaneous mutation rates at the same set of loci in several non-Belarusian populations were similar to those in Belarus. The estimated mean radiation dose to the liquidators was small, being about 39 mSv, and this might be one reason why no increases in mutation rates due to radiation could be found.

Adult↗

Thyroid disease in northern Italian children born around the time of the Chernobyl nuclear accident.

BACKGROUND: The Chernobyl nuclear accident of 1986 caused a dramatic increase in the incidence of thyroid cancers in exposed children in Belarus. Airborne radioactivity from the reactor spread over northern Italy, where rainout gave rise to low levels of radioactivity at ground level. PATIENTS AND METHODS: As the latency between exposure to ionising radiation and development of thyroid cancer is thought to be about 10 years, in 1996/1997 all children born in 1985 and 1986 and attending school in an area of Milan, Italy were examined for thyroid nodules. A total of 3949 children were examined by two physicians blinded to the examination and diagnosis of the other. The children were to be reassessed in 2001/2002. RESULTS: In total, 1% had palpable nodules. The nodule diagnoses were: Hurtle cell adenoma (one), thyroglossal duct cyst (one), thyroid cyst (four) and thyroiditis (four). The prevalence of thyroid disease in the cohort was indistinguishable from that of populations not exposed to radioactive pollution. Only 10 children re-presented for examination 5 years later; all were negative. The direct costs of the study were estimated at 21,200 Euros. CONCLUSION: The high cost of the study in relation to reassuring lack of increase in thyroid nodule prevalence suggests that further studies are not justified.

Chernobyl Nuclear Accident↗

Biological estimates of dose to inhabitants of Belarus and Ukraine following the Chernobyl accident.

The purpose of this paper is to investigate how well various assays on blood can detect radiation dose to people exposed many years previously and, if possible, to estimate that dose. The assays were applied to persons resident close to Chernobyl in 1986. Blood samples were taken 13-15 years after the reactor accident. The assays used were the frequencies of lymphocyte chromosomal translocations, micronuclei, HPRT mutations and apoptotic cells. Translocation yields in the exposed groups were marginally higher than in their respective controls, leading to dose estimates of about 0.2 Gy but with large uncertainties. All other assays showed inconsistency from person to person or other variations apparently not related to dose. The measurement of translocations, it is concluded, is the biological method of choice for retrospective dosimetry.

Adult↗

A cytogenetic follow-up of some highly irradiated victims of the Chernobyl accident.

A follow-up of 10 highly irradiated men, mostly reactor crew, from the Chernobyl accident is described. Their pre-accident medical conditions and relevant medical status approximately 10-13 y later are listed. A comparison is made between estimates of their average whole-body penetrating radiation doses derived from several biological parameters. First estimates were based on their presenting severity of prodromal sickness, early changes in blood cell counts and dicentric chromosome aberrations in lymphocytes. In three cases ESR measurements on tooth enamel were also made. Retrospective dosimetry using FISH translocations was attempted 10-13 y later. This showed good agreement for those patients with the lower earlier dose estimates, up to about 3 Gy. For the others, extending up to about 12 Gy, the translocations indicated lower values, suggesting that in these cases translocations had somewhat declined. Repeated chromosomal examinations during the follow-up period showed an expected decline in dicentric frequencies. The pattern of decline was bi-phasic with a more rapid first phase, with a half-life of approximately 4 months followed by a slower decline with half-lives around 2-4 y. The rapid phase persisted for a longer time in those patients who had received the highest doses. 10-13 y later dicentric levels were still above normal background, but well below the translocation frequencies.

Adult↗

Measurement of the whole-body 137Cs in residents around the Chernobyl nuclear power plant.

To understand the current situation of internal radiation exposure in the population around the Chernobyl Nuclear Power Plant (CNPP), we examined the 137Cs body burden in six residents of Belarus, Ukraine and Russia in 2002 and 2004 using the whole-body counter (WBC) at Nagasaki University (Japan). The data were compared with those of our previous study performed in 1993-1994 using the same method. In 2002 and 2004, peaks of 137Cs were detected in two residents from Gomel, which was heavily contaminated by the CNPP accident, one from Minsk (Belarus) and one from Kiev (Ukraine), but another resident from Minsk showed no 137Cs peaks. The results of the present study suggests that residents around the CNPP are still exposed to chronic 137Cs internal irradiation, probably due to the daily consumption of contaminated domestic foods, but the risk of any disease by the irradiation is quite low. Long-term follow-up of WBC around the CNPP is useful and may contribute to radiation safety regulation together with a reduction of unnecessary radiophobia for the residents.

Adult↗

Non-cancer thyroid diseases among children in the Kaluga and Bryansk regions of the Russian Federation exposed to radiation following the Chernobyl accident.

This paper presents results of estimated radiation risks of non-cancer thyroid diseases in the people from Kaluga and Bryansk regions of the Russian Federation exposed in their childhood to radioiodine as a result of the Chernobyl accident. This work was carried out under the Joint Medical Research Project on non-cancer thyroid diseases conducted by Sasakawa Memorial Health Foundation and the Medical Radiological Research Center of the Russian Academy of Medical Sciences. The subjects were 2,457 people who underwent health examinations from 1997 to the end of 1999 who had individual radiometric thyroid data obtained between May and June 1986 and were aged 10 y or less at the time of exposure. The thyroid absorbed doses from incorporated 131I were estimated on the basis of measurements of exposure dose rate in the vicinity of the subject's thyroid and liver. A compartment model accounting for 131I metabolism in humans and cows was used. The estimated dose varied from 0 to 6 Gy, and its distribution was approximately lognormal with a mean of 0.132 Gy and standard deviation of 0.45 Gy. The prevalence of diffuse goiter in males showed a significant dose-response (p = 0.03) with an estimated odds ratio 1.36 at 1 Gy.

Chernobyl Nuclear Accident↗

Retrospective luminescence dosimetry: development of approaches to application in populated areas downwind of the Chernobyl NPP.

The cumulative absorbed dose in fired-clay bricks collected from ten buildings in the populated contaminated settlement (137Cs, 1,470 kBq m(-2)) of Stary Vishkov, located 175 km downwind of the Chernobyl Nuclear Power Plant (NPP) in the Bryansk administrative region of Russia, was determined using luminescence techniques by five laboratories. At each location, the cumulative dose, after subtraction of the natural background dose, was translated to absorbed dose in air using conversion factors derived from Monte Carlo simulations. The simulations employed source distributions inferred from contemporary soil contamination data and also took into account heterogeneity of fallout deposition. At four locations the cumulative dose at a reference location was calculated, enabling the luminescence determinations to be compared directly with values of cumulative absorbed dose in air obtained using deterministic models. A "local" conversion factor was also derived from the Monte Carlo simulations for locations where the disturbance of soil was significant. Values of the "local" cumulative dose in air calculated using this factor were compared with those predicted using the deterministic models at each sampled location, allowing location factors to be calculated. The methodology developed is generally applicable to populated areas contaminated by radioactive fallout in which brick buildings are found. The sensitivity of the luminescence techniques for bricks from this region of Russia was sufficient to evaluate cumulative absorbed dose in brick due to fallout of less than 20 mGy.

Air Pollutants, Radioactive↗

Dietary iodine intake in residents of northwestern regions of ukraine contaminated by the chernobyl accident.

Daily iodine intake in Ukrainian subjects of northwestern regions was estimated in relation to the health effects on inhabitants after the Chernobyl accident. Total diets were collected from 106 locations for children and adult males by a duplicate portion study. Iodine was rapidly determined by inductively coupled plasma mass spectrometry after chemical separation. Iodine concentration on a dry basis for Ukrainians was 0.11 microg g(-1) and the daily iodine intake was in the range of 2.80-372 microg per person. The median, geometric mean, and standard deviation were 28.1, 32.7, and 2.51 microg, respectively. The yearly trend of the intake had almost no change. Regional differences would be expected to exist among the 10 areas of the Ukraine, but no clear differences appeared in the present findings. Daily iodine intake in Ukrainians was lower than the recommended dietary intake (RDI) allowance (150 microg), and its lack would be related to the high prevalence of goiter in the country.

Adult↗

Chernobyl and Goiânia lessons for responding to radiological terrorism.

The deployment of a radiological dispersal device (RDD) is likely to result in relatively low radiation exposure of the targeted population, insufficient to cause a severe radiation detriment. Nevertheless, due to atmospheric dispersion of the radioactive material, an urban area equaling several city blocks could be affected. The current knowledge base concerning the response to radiological terrorism, focusing mainly on environmental cleanup and site recovery (CSR) of areas with radioactive contamination due to the deployment of an RDD, is largely derived from military scientific tests or exercises assembled over the past 50 y with only limited applicability to the consequences of an RDD detonating in a city. This paper focuses on the extensive experience in CSR gained in the management of the radiological accident contaminating the Brazilian city of Goiânia in 1987, and managing the aftermath of the Chernobyl reactor accident in 1986. The incident in Goiânia demonstrated the numerous practical difficulties of implementing a sound CSR, based on a balanced judgment of all relevant factors, such as radiation safety, environmental issues, economic consequences, and public fear. A review of the different stages of the intervention policy in the former Soviet Union reveals that risk-benefit cost analysis was not used for the decision-making process during the later stages of the post-accident situation. Instead, a CSR policy was adopted that resulted in continuously escalating costs. The results of this analysis are used to develop an Integrated Cleanup and Site Restoration Concept and recommend practically applicable solutions from Lessons Learned.

Brazil↗