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PubMed1992

Chernobyl fallout: internal doses to the Norwegian population and the effect of dietary advice.

Dietary studies and whole-body measurements were used to estimate the intake of radiocesium and the radiation dose received by different groups of people in Norway after the Chernobyl accident. Freshwater fish, milk, and reindeer meat were the major sources for radiocesium intake. Dietary advice, together with agricultural decontamination measures, resulted in a considerable reduction in the exposure level of the population. A majority (40-80%) of the specially selected groups (farmers-hunters and Sami reindeer herdsman) changed its diet significantly after the accident. Without dietary changes, specifically a reduction in the consumption of freshwater fish and reindeer meat, the Sami group would have had a 400-700% higher radiocesium intake, and the farmers-hunters' intake would have been up to 50% higher than what they actually had experienced.

Accidents↗
PubMed1992

137Cs uptake with cafeteria food after the Chernobyl accident.

After the Chernobyl accident, the activity concentrations of radiocesium were measured in both the meals served at the cafeteria of a research center and in the employees eating there. The time-dependent means of monthly 137Cs activities in meals and people show a similar distribution pattern with highest values between March and July 1987, i.e., only 1 y after the accident. In meals, the highest activities were found when the menu consisted of pork, milk, or milk products. The 50-y cumulative effective dose calculated from the whole-body measurements is 0.21 mSv for male and 0.15 mSv for female employees. Cafeteria food contributed only a small share to this exposure.

Accidents↗
PubMed1993

Profiles and downward migration of 134Cs and 106Ru deposited on Italian soils after the Chernobyl accident.

After the Chernobyl accident, several radionuclides were deposited on the soil of the Piemonte Region in Italy. Contamination values were monitored and the initial vertical soil profiles of 134Cs and 106Ru were determined. For both radionuclides, more than 60% of the total activity remained in the upper 1-cm layer of soil during the first 7 mo after the accident. The time history of the soil profiles was studied over a period of 3 y in two Piedmontese localities. A compartmental model was also developed to describe downward migration of 134Cs and 106Ru. The results indicated a low mobility for both radionuclides. The change in their vertical profiles may be described using a box model with a transfer constant of 0.2 y-1 for 134Cs and 0.3 y-1 for 106Ru between 1-cm-thick layers. A strong association between the soil fine fraction and the mobility of both radionuclides was also found.

Accidents↗
PubMed1993

Differences in the sensitivity of barley varieties to direct cesium contamination from the Chernobyl accident.

A number of winter and spring barley (Hordeum vulgare L) varieties were tested for sensitivity to direct cesium contamination in Denmark arising from the Chernobyl accident. Significant differences among varieties were revealed which were independent of crop growing conditions. Results indicate that different sensitivities among varieties result from genetic or morphological differences.

Accidents↗
PubMed1993

137Cs transfer after Chernobyl from fodder into chicken meat and eggs.

The distribution and the biological half-lives of 137Cs in poultry after continuous intake of foodstuffs contaminated by the Chernobyl fallout were studied in order to determine transfer coefficients to yolk, albumen, and shell of eggs as well as transfer coefficients to chicken meat. Mean values for laying hens were found to be 0.2 d kg-1 (whole consumable egg), 1.2 d kg-1 (leg meat), and 1.6 d kg-1 (breast meat) when radiocesium was fed in contaminated grass pellets, and about twice as large [i.e., 0.4 d kg-1 (whole consumable egg), 2.8 d kg-1 (leg meat), and 3.0 d kg-1 (breast meat)] when radiocesium was fed in contaminated wheat. Reducing effects of the feed additive ammonium-ferric-cyano-ferrate in concentrations of 0.66 g kg-1 of feed mixture on the contamination of hen products were quantified to be a factor of 3 to 4 (whole consumable egg and meat after grass pellet feeding) and 8 to 14 (whole consumable egg and meat after wheat feeding). A drastically higher reduction with an ammonium-ferric-cyano-ferrate dose twice as large (1.33 g kg-1) was achieved. For broiler chickens, activity concentration ratios of meat to feed were derived for various fattening periods, with mean values of about 0.3 (leg), 0.4 (breast), and 0.2 (liver). The addition of ammonium-ferric-cyano-ferrate reduced the activity concentrations in meat by factors of more than 6.

Accidents↗
PubMed1993

Plutonium in daily diet in Poland after the Chernobyl accident.

The content of 239,240Pu was determined in the daily diet collected in northeastern Poland (Bialystok) from March 1987 to May 1992. The estimated annual intake of plutonium decreased from 774 mBq y-1 in the first year after the Chernobyl accident down to approximately 90 mBq y-1 in the sixth year. Large fluctuations of daily intake in the first 2 y suggested that a large fraction of plutonium in the daily diet originated from the external contamination. Assuming the fractional absorption factor of 10(-5) for externally contaminated foodstuffs and 10(-3) for root uptake, the assimilated 239,240Pu would be in the range from approximately 0.02 mBq up to approximately 2 mBq for the period studied.

Accidents↗
PubMed1994

Thyroid doses resulting from the Ukraine Chernobyl accident--Part I: Dose estimates for the population of Kiev.

In the context of the radiation exposure of the Ukrainian population resulting from the Chernobyl accident, the quantification of the thyroid doses due to iodine incorporation is of special interest. This first part of a series of planned publications deals with the dose and risk estimation for Kiev citizens. Although these doses are expected to be considerably lower than those for some other regions of Ukraine, the investigations started with this population because the quantification of the thyroid doses due to iodine incorporation is of special interest. This first part of a series of planned publications deals with the dose and risk estimation for Kiev citizens. Although these doses are expected to be considerably lower than those for some other regions of Ukraine, the investigations started with this population because of the availability of rather reliable measurements and because of the size of this population. The methods developed allowed the estimation of individual thyroid doses. The average values of individual thyroid doses for five age groups (birth years 1983-1986, 1979-1982, 1975-1978, 1971-1974, and < 1971) are 104, 62, 19, 18, and 41 mGy, respectively. The collective thyroid doses were estimated as 83 x 10(3) person-Gy for those born before 1971 and as 38 x 10(3) person-Gy for younger inhabitants. The numbers of expected thyroid cancers in the whole Kiev population are 66 and 130, respectively.

Accidents↗
PubMed1994

Transfer kinetics and coefficients of 90Sr, 134Cs, and 137Cs from forage contaminated by Chernobyl fallout to milk of cows.

A experiment was conducted to study kinetics, transfer coefficients, and biological half-lives of 90Sr, 134Cs, and 137Cs from feed to milk. A cow was fed a diet containing alfalfa hay contaminated by Chernobyl fallout for 14.5 wk. The time-dependent activity in milk was approximated by a two-compartment model with fast biological half-lives of 2, 0.9, and 1 d and slow biological half-lives of 36.9, 8.7, and 12.4 d for 90Sr, 134Cs, and 137Cs, respectively. The transfer coefficients determined in the experiment were 0.0008 d L-1 for 90Sr, 0.0029 d L-1 for 134Cs, and 0.0031 d L-1 for 137Cs. The biological elimination phases of 134Cs and 137Cs were described by a two-compartment model while a one-compartment model was proposed for 90Sr.

Accidents↗
PubMed1994

Statistical analysis of radioactive contamination levels in settlements of the Chernobyl middle zone.

A statistical analysis of the measurements of 137Cs activity density carried out in 1990-1991 in 30 settlements of the mesozone (and partially in the nearest zone) of the Chernobyl nuclear power plant is presented. It is shown that the mean activity density of radionuclides is close to 14 Bq cm-2 for the inspected settlements of Byelorussia which is significantly less than that for the inspected settlements of the nearest zone (48 Bq cm-2). The analysis shows that there is a near linear correlation between rms deviation of activity density and its mean value. It is also shown that the correlation radius of the data is comparable with the spatial step of the measurements and that the activity density distribution is reasonably described in terms of a normal distribution.

Accidents↗
PubMed1994

Retrospective reconstruction of individual and collective external gamma doses of population evacuated after the Chernobyl accident.

About 90,000 citizens of Ukraine, who were residents of the near zone of the Chernobyl nuclear power plant were evacuated during the first weeks after the accident due to the heavy contamination of the environment. Doses of this cohort were unknown. Retrospective reconstruction of external gamma exposure doses, based on the results of direct dose rate measurements performed during the accident and individual behavior/migration histories of the evacuees, was performed. Individual doses were reconstructed for 30,586 evacuees from the city of Prip'at and the settlements of the 30-km zone. The average effective dose H(E) due to external irradiation for this cohort was estimated to be 15 mSv, although individual values vary in an extremely wide range from 0.1 to 383 mSv. The collective dose of the whole evacuated population was found to be 1,300 person-Sv.

Accidents↗
PubMed1994

Radiocesium in diet and humans in northeastern Poland after the Chernobyl accident.

137Cs and 134Cs concentrations were determined in the daily diet and foodstuffs in northeastern Poland in the fourth through sixth years after the Chernobyl accident. Intakes, body burdens, and dose equivalents were evaluated in the consecutive years. The data from this and previous work were used for the calculation of the effective half-time of radiocesium in humans. The effective half-time for 137Cs (1.94 y) was similar to that observed after nuclear weapons tests. The effective half-time for 134Cs was 0.98 y. Taking these half-times into account, the whole-body committed dose equivalent for the adult population was estimated to be 256 microSv; it was about 50% higher than that after the nuclear weapons tests.

Accidents↗
PubMed1994

Analysis of the effectiveness of emergency countermeasures in the 30-km zone during the early phase of the Chernobyl accident.

Some radiation-emergency countermeasures, including evacuation, were implemented in the settlements of the 30-km zone during the early phase of the accident at the Chernobyl Nuclear Power Plant. These countermeasures are described and compared with the international recommendations. An analysis of the effectiveness of the emergency countermeasures was conducted based upon the results of a wide-scale public survey. Quantitative assessments of the effectiveness (dose reduction) of the countermeasures were derived.

Disaster Planning↗
PubMed1995

Prevalence of lens changes in Ukrainian children residing around Chernobyl.

The objective of this study is to determine the prevalence and characteristics of lens changes in the eyes of a pediatric population, 5-17 y old, living in the permanent control zone around the Chernobyl nuclear reactor and to compare these findings with those from an unexposed control population. A total of 1,787 children are reported on (996 exposed and 791 unexposed). Over three-quarters of the subjects examined in this study show a form of minor change, termed focal lens defect, in the cortical and/or nuclear portions of the lens of the eye. The exposed group shows a small (3.6%), but statistically significant excess (p = 0.0005) of subclinical posterior subcapsular lens changes similar in form to changes identified in atomic bomb survivors. These posterior subcapsular changes tend to occur in boys 12-17 y old and in exposed children who report consuming locally grown mushrooms on a regular basis.

Adolescent↗
PubMed1995

Radiocesium body burdens in immigrants to Israel from areas of the Ukraine, Belarus and Russia near Chernobyl.

Of the 500,000 immigrants from the former Soviet Union who came to Israel during 1990-1993, about 100,000 are estimated to have come from radiocontaminated areas near Chernobyl. These people were subject to chronic uptake of environmental radiocesium over protracted periods. During October-November 1991, a joint Israeli-Canadian investigation measured radiocesium body burdens in immigrants to Israel from the Ukraine, Belarus, and the southern Russian republic in order to provide factual information on radiocesium levels to concerned immigrants and to relate the body burdens to the geographic area of residence before coming to Israel. Assessments were made of 137Cs body burdens in 1,228 volunteer men, women, and children. These measurements were accompanied by medical assessments based on clinical histories and examinations. Radiocesium levels were strongly dependent on the duration of residence in Israel, with the highest levels being found in the most recent immigrants. The maximum level, extrapolated back to the time of leaving the former Soviet Union, was estimated to be about 0.83 kBq (10.3 Bq kg-1). Of the most recent immigrants from the Kiev region (< 101 days in Israel), only 15% had back extrapolated body burdens > 50 Bq, whereas 53% of those coming from Gomel and other towns in the contaminated zones (> 3.7 x 10(10) Bq km-2 of radiocesium) had detectable levels > 50 Bq. People coming from the latter region had significantly higher body burdens as compared to those from the former, in accordance with the higher degree of ground radiocesium contamination reported for the latter region. Women and children showed considerably lower total radiocesium content in comparison to men. All radiocesium body burdens at the time of measurement were too low to be of health concern.

Adolescent↗
PubMed1995

Estimates of thyroid equivalent dose in Lithuania following the Chernobyl accident.

The volatile radioiodine was detected in Lithuania in the very first days after the Chernobyl accident. The proportion of gaseous 131I species of airborne iodine identified during that period exceeded from 2 to 4 times the aerosol fraction. The radioiodine activity of milk consumed by inhabitants of Lithuania varied over a broad range. 131I activity in milk reached a peak on the fourth day after deposition and then decreased with an effective half-time ranging from 4.2 +/- 0.6 d to 5.2 +/- 0.9 d. Thyroid examinations by dosimetric teams were not available in Lithuania for reasons beyond the control of experimenters. Because of this, thyroid equivalent doses were estimated using the modified ICRP three-compartment cyclic model. These calculations applied Monte Carlo methods and consideration of regional iodine deficiency to generate frequency distributions of equivalent doses to the infant and adult thyroid gland in three areas of Lithuania with different contamination levels.

Adult↗
PubMed1996

Opportunities for the testing of environmental transport models using data obtained following the Chernobyl accident.

The aftermath of the Chernobyl accident has provided a unique opportunity to collect data sets specifically for the purpose of model testing, and with these data to create scenarios against which environmental transport models may be tested in a format constituting a blind test. This article serves as an introduction to three test scenarios designed for testing models at the process level: (1) surface water contamination with radionuclides initially deposited onto soils; (2) contamination of different aquatic media and biota due to fallout of radionuclides into a body of water; and (3) atmospheric resuspension of radionuclides from contaminated land surfaces. These scenarios are the first such tests to use data sets collected in the former Soviet Union. Interested modelers are invited to participate in the test exercises by making calculations for any of these test scenarios. Information on participation is included.

Models, Biological↗
PubMed1996

Effective doses due to external irradiation from the Chernobyl accident for different population groups of Ukraine.

A model for the external exposure of the Ukrainian population after the Chernobyl accident was developed. It is based on extensive measurements of external gamma-exposure rates (EGER) in air and of external effective doses of members of five population groups. Questionnaires were used to determine the occupancy times of members of the population groups at three types of locations; inside houses, outdoors, and outside of the home settlement. Behavior factors are defined as the ratio of individual external doses to a reference dose for a phantom standing permanently over an open field with the same average 137Cs activity per unit area as in the settlement. The behavior factors were derived for five population groups (children younger than seven years, the age group from eight to seventeen years, employees, agricultural workers, and pensioners) by two methods: first from direct measurements of individual doses by thermoluminescent dosimetry and an experimental determination of the average 137Cs activity per unit area in the settlement of interest; and second from external gamma-exposure rates in air at various types of locations and from the questionnaire data. The methods were found to be consistent and the results were used to calculate external exposures of the five population groups in the years 1987 through 1991.

Adult↗