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PubMed1998

Multifractal analysis of the 137Cs fallout pattern in Austria resulting from the Chernobyl accident.

The cumulative deposition of the 137Cs fallout in Austria resulting from the passage of the Chernobyl cloud has been investigated by applying correlation dimension and hyperbolic frequency distribution methods. For the analysis, a total of 1,881 deposition values were used, which were collected by the Federal Environmental Agency of Austria and the Federal Ministry of Health, representing all available measurements of 137Cs in soil made in Austria after the Chernobyl accident. From these data a hyperbolic exponent for the frequency distribution of 4.0 and a set of fractal correlation dimensions, which decrease from 1.426 +/- 0.022 (for the whole network) to 0.706 +/- 0.047 (for 137Cs values > or = 100 kBq m(-2)), were derived, thus confirming that the fallout pattern can be described as a multifractal.

Austria↗
PubMed1996

Model testing using Chernobyl data: III. Atmospheric resuspension of radionuclides in Ukrainian regions impacted by Chernobyl fallout.

The "Resuspension" scenario is designed to test models for atmospheric resuspension of radionuclides from contaminated soils. Resuspension can be a secondary source of contamination after a release has stopped, as well as a source of contamination for people and areas not exposed to the original release. The test scenario describes three exposure situations: (1) locations within the highly contaminated 30-km zone at Chernobyl, where exposures to resuspended material are probably dominated by local processes; (2) an urban area (Kiev) outside the 30-km zone, where local processes include extensive vehicular traffic; and (3) a location 40 to 60 km west of the Chernobyl reactor, where upwind sources of contamination are important. Input data include characteristics of the 137Cs ground contamination around specific sites, climatological data for the sites, characteristics of the terrain and topography, and locations of the sampling sites. Predictions are requested for average air concentrations of 137Cs at specified locations due to resuspension of Chernobyl fallout and for specified resuspension factors and rates. Test data (field measurements) are available for all endpoints.

Air Pollutants, Radioactive↗
PubMed1989

Isolation and characterization of hot particles from Chernobyl fallout in southwestern Finland.

Three types of activity composition have been found in airborne hot particles that were transported long distances from the Chernobyl accident. Their characterization is based on the analysis of single particles isolated from Pinus Sylvestris needles. The average activity of the particles was 130 Bq at the time of the accident. The most common type of particle contains the radioactive species 141Ce, 144Ce, 95Zr and 95Nb; the second type includes 103Ru and 106Ru along with the previous isotopes; and the third contains 103Ru and 106Ru only. Cesium-134 and -137 were present only in very small amounts. The activity composition of the Chernobyl reactor core fuel was similar to the composition of the first and second type particle; apparently the core fuel was only partially volatilized. The main bulk composition of the particles is shown to be U. The average aerodynamic size of the identified hot particles is 10 microns. The particles are rectangular or pentagonal in shape.

Accidents↗
PubMed1995

Chromosome aberrations in Norwegian reindeer following the Chernobyl accident.

Chromosome analyses were carried out on peripheral blood lymphocytes of semi-domestic reindeer in Norway which had been exposed to varying amounts of radiocesium emanating from the Chernobyl accident. The sampling was done in the period 1987-1990. The material included 192 reindeer, originating from four herds in central Norway, an area considerably affected by fallout from the Chernobyl accident, and from three herds in northern Norway which was unaffected by fallout from the accident. Significant heterogeneity in the distribution of chromosome aberrations between herds was observed. The pattern of chromosome aberration frequencies between herds was not related to the variation in radiocesium exposure from the Chernobyl accident. Other factors than the Chernobyl accident appear therefore to be of importance for the distribution of aberration frequencies found among present herds. Within the most contaminated area the reindeer born in 1986 showed significantly more chromosome aberrations than those born both before and after 1986. This could suggest that the Chernobyl accident fallout created an effect particularly among calves, during the immediate post-accident period in the most exposed areas.

Animals↗
PubMed2002

Radiation doses to local populations near nuclear weapons test sites worldwide.

Nuclear weapons testing was conducted in the atmosphere at numerous sites worldwide between 1946 and 1980, which resulted in exposures to local populations as a consequence of fallout of radioactive debris. The nuclear tests were conducted by five nations (United States, Soviet Union, United Kingdom, France, and China) primarily at 16 sites. The 16 testing sites, located in nine different countries on five continents (plus Oceania) contributed nearly all of the radioactive materials released to the environment by atmospheric testing; only small amounts were released at a fewother minor testing sites. The 16 sites discussed here are Nevada Test Site, USA (North American continent), Bikini and Enewetak, Marshall Islands (Oceania); Johnston Island, USA (Oceania), Christmas and Malden Island, Kiribati (Oceania); Emu Field, Maralinga, and Monte Bello Islands, Australia (Australian continent); Mururoa and Fangataufa, French Polynesia (Oceania), Reggane, Algeria (Africa), Novaya Zemlya and Kapustin Yar, Russia (Europe), Semipalatinsk, Kazakhstan (Asia), and Lop Nor, China (Asia). There were large differences in the numbers of tests conducted at each location and in the total explosive yields. Those factors, as well as differences in population density, lifestyle, environment, and climate at each site, led to large differences in the doses received by local populations. In general, the tests conducted earliest led to the highest individual and population exposures, although the amount of information available for a few of these sites is insufficient to provide any detailed evaluation of radiation exposures. The most comprehensive information for any site is for the Nevada Test Site. The disparities in available information add difficulty to determining the radiation exposures of local populations at each site. It is the goal of this paper to summarize the available information on external and internal doses received by the public living in the regions near each of the mentioned nuclear test sites as a consequence of local fallout deposition.

Atmosphere↗
PubMed2005

Decrease of total activity with time at long distances from a nuclear accident or explosion.

Two data groups were analyzed: (1) the exposure rate in the former Czechoslovakia after the Chernobyl accident in 1986, and (2) the decrease of beta activity of an atmospheric fallout sample taken in Bratislava during 24 h on 30 May 1965. Both quantities decreased with the first power of time. This pattern of decrease is explained by applying the same mathematical formalism as is also used to describe the decrease in postnatal mortality with age. Following this formalism, the decrease of total activity with the first power of time could be seen as a consequence of a log-normal distribution of decay constants in the fallout. This differs slightly from earlier results that show the total activity decreasing with a power of 1.2 immediately after the nuclear explosion.

Chernobyl Nuclear Accident↗
PubMed2004

[Cleft lip and cleft palate birth rate in Bavaria before and after the Chernobyl nuclear power plant accident].

BACKGROUND: Cleft lip and palates (CLP) occur with a frequency of between 1 and 2 cases in 1000 live births and thus belong to the most frequent congenital anomalies. In the former German Democratic Republic (GDR), records covering 1967-1989 for CLP newborns show a 9.4% increase of the prevalence of CLP from 1987 to 1989, possibly due to Chernobyl. DATA AND STATISTICAL METHOD: In Bavaria, all congenital malformations in children's hospitals have been recorded from 1984 to 1991. Among these data, 1324 cases with CLP were found. A spatial-temporal analysis aimed at uncovering a possible association of the CLP occurrence with the Chernobyl fallout on a district level, as well as a synoptic analysis of the GDR and Bavarian data, were carried out. RESULTS: In Bavaria, from October 1986 to December 1990, the CLP frequency increased by 9.5% (p=0.10) relative to the trend as computed from the remaining years. The association of CLP rates with fallout on a district level is reflected by a significant relative risk (RR) per kBq/m(2) of RR=1.008 (p=0.03). A synoptic analysis of the Bavarian data and the GDR data restricted to the overlapping time window from 1984 to 1989 discloses a simultaneous significant jump of the CLP prevalence by 8.6% (p=0.02) after 1986. CONCLUSION: The presumption of a long-term increase of CLP after exposure to Chernobyl fallout is corroborated by the analysis of the Bavarian congenital malformation data.

Abnormalities, Radiation-Induced↗
PubMed1987

Carcinogenicity of radiation doses caused by the Chernobyl fall-out in Sweden, and prevention of possible tumors.

The fallout from the Chernobyl reactor resulted in radioactive fall-out in eastern Sweden leading to a ground radiation intensity of between 2 and 500 microR h-1 above the 10-15 microR h-1 background, an average external cumulative dose of about 3-4 mSv (0.3-0.4 rem) to about 1 million people, or about 3500 man-Sv (350,000 man-rem) over 50 years, or 70 man-Sv per year with a maximum dose to a few individuals of 40 mSv. The corresponding figures reported for civilians around Chernobyl is 8.6 million man-rem in 1986 and 29 million man-rem over 50 years, or 600,000 man-rem (equivalent to about 6000 man-Sv) per year. If Swedish doses are averaged over the whole population, the average is about 1 mSv or 10,000 man-Sv, or 200 man-Sv per year. The thyroid uptake of 131I is approximately 0.1-0.2 kBq (0.005 microCi) and the total body uptake of 137Cs, 1 kBq (0.03 microCi), resulting in an approximate internal dose of 0.02 mSv. If a linear dose-response curve is assumed, an increase of the normal cancer mortality incidence in the million Swedes affected by 3500 man-Sv per 50 years from 200,000 to about 200,070 can be assumed. Corresponding figures for all of Sweden are 8,000,000 inhabitants, 7000 man-Sv, 1,720,000 normal cancer deaths, and 1,720,140 expected cancer deaths. Corresponding figures reported for the population outside the 30 km evacuation zone around Chernobyl are 300,000 man-Sv, and an increase from 6,800,000 cancer deaths per 50 years to 6,806,000 cancer deaths.

Accidents↗
PubMed2003

Territory contamination with the radionuclides representing the fuel component of Chernobyl fallout.

The data obtained through a series of experiments were used to specify the correlation of activities of the fuel component radionuclides of Chernobyl fallout and to create the maps of the 30-km Chernobyl zone terrestrial density of contamination with 154Eu, 238Pu, 239+240Pu and 241Am (on 01.01.2000). In the year 2000, total inventories of the fuel component radionuclides in the upper 30-cm soil layer of the 30-km Chernobyl zone in Ukraine (outside the ChNPP industrial site, excluding the activity located in the radioactive waste storages and in the cooling pond) were estimated as: 90Sr--7.7 x 10(14) Bq; 137Cs--2.8 x 10(15) Bq; 154Eu--1.4 x 10(13) Bq; 238Pu--7.2 x 10(12) Bq; 239+240Pu--1.5 x 10(13) Bq; 241Am--1.8 x 10(13) Bq. These values correspond to 0.4-0.5% of their amounts in the ChNPP unit 4 at the moment of the accident. The current estimate is 3 times lower than the previous widely-cited estimates. Inventories of the fuel component radionuclides were also estimated in other objects within the 30-km zone and outside it. This allowed more accurate data to be obtained on the magnitude of a relative release of radionuclides in the fuel particles (FP) matrix during the Chernobyl accident outside the ChNPP industrial site. It amounts to 1.5+/-0.5% of these radionuclides in the reactor, which is 2 times lower than the previous estimates. Two-thirds of the radionuclides release in the FP was deposited on the territory of Ukraine.

Environmental Monitoring↗
PubMed1987

Fallout, radiation doses near Dounreay, and childhood leukaemia.

Possible explanations for the recently reported increased incidence of childhood leukaemia around Dounreay were examined in the light of changes in the national incidence of leukaemia that occurred during the period of exposure to fallout from international testing of nuclear weapons in the atmosphere. It was concluded that the increase could not be accounted for by an underestimate of the risk of leukaemia per unit dose of radiation at low doses and low dose rates, nor by an underestimate of the relative biological efficiency of high as compared with low linear energy transfer radiation. One possible explanation was underestimation of doses to the red bone marrow due to the discharges at Dounreay relative to the dose from fallout, though investigation of ways in which this might have occurred did not suggest anything definite. Other possible explanations included a misconception of the site of origin of childhood leukaemia, outbreaks of an infectious disease, and exposure to some other, unidentified environmental agent. These findings weigh heavily against the hypothesis that the recent increase in childhood leukaemia near Dounreay might be accounted for by radioactive discharges from nuclear plants, unless the doses to the stem cells from which childhood leukaemia originates have been grossly underestimated.

Adolescent↗