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Childhood leukemia and fallout from the Nevada nuclear tests.

Cancer mortality data from the National Center for Health Statistics, covering the period 1950 through 1978, were used to test a reported association between childhood leukemia and exposure to radioactive fallout from nuclear weapons tests in Nevada between 1951 and 1958. No pattern of temporal and geographic variation in risk supportive of the reported association was found. Comparison of these results with those presented in support of an association of risk with fallout suggests that the purported association merely reflects an anomalously low leukemia rate in southern Utah during the period 1944 to 1949.

Adolescent↗

Determining the collection efficiency of gummed paper for the deposition of radioactive contaminants in simulated rain.

An extensive network of gummed paper collectors was used during the 1950s for routine monitoring of radioactive fallout from weapons testing. The experiments reported in this paper were designed to examine the collection efficiency of gummed paper for wet deposition of several types of soluble and insoluble radioactive contaminants under conditions similar to those found during natural rainstorms. The collection efficiencies for each substance were determined over a range of rainfall amounts and at two separate rainfall intensities. The collection efficiency of the gummed paper is highest for large insoluble particles and lowest for soluble ionic substances. The values for 7Be and 131I ranged from about 0.30 (30%) at 2.5 mm of rain to 0.04-0.06 (4%-6%) at 20 mm of rain. These values were negatively correlated with the amount of rain and were unaffected by rain intensity. This suggests that the collection efficiency of either ion is simply a matter of rapid saturation and runoff. Neither rain amount nor rain intensity has much effect on the collection efficiency of large insoluble particles. These particles seem to settle readily onto the surface of the gummed paper from which they are not easily removed by additional rain. Analysis of the collection efficiencies of the gummed paper included the activity of both the gummed paper and the standing water on the paper. A large portion of the activity for the ionic substances was found in the standing water. There was less activity by insoluble particles in standing water. This indicates that for estimates of deposition of soluble substances, considerable bias could be introduced into the results if the standing water is discarded prior to analysis.

Adhesives↗

Measurement of 239Pu in soil and plants in the Nishiyama District of Nagasaki.

Nishiyama district in Nagasaki is located approximately 3000 m east of the hypocenter of the atomic bomb that was dropped on 9 August 1945. This district is also known as an area where there was a concentrated radioactive fallout with the black rain that was carried by a westerly wind. The Nagasaki atomic bomb was a Pu bomb, and the fallout must have included 239Pu without fission in addition to fission products. The presence of 239Pu in Nishiyama district has been confirmed previously. In this study, the distribution of 239 + 240Pu concentration in the uncultivated soil and the transfer factor of 239 + 240Pu to agricultural products in Nishiyama district were examined. The concentration of 239 + 240Pu in the uncultivated soil was 20 Bq kg-1, which was approximately eight times as high as that in the control districts. The transfer factor of 239 + 240Pu to agricultural products was 10(-4) - 10(-3), which was 1/100-1/200 of that of 137Cs.

Agriculture↗

[Pregnancy outcome in some Norwegian counties before and after the Chernobyl accident].

The outcome of pregnancies in six countries in Norway has been studied during 12 months prior and subsequent to the Chernobyl accident. The accident took place in a period with an annual increase of births of approximately 3%. However, the year after the accident a decrease of 0.7% was observed with particularly low numbers during February--April 1987. Concomitantly, the miscarriage fraction of all pregnancies increased by 16.3% and particularly during November 1986--January 1987. The same pattern was found when observations from Haukeland Hospital were analyzed separately. When the time of conception was taken into consideration we found that conceptions during the period May--July 1986 ended more often as miscarriages. We have no explanation of the observations. The external radiation exposure seems too small to have produced these effects. The internal radiation from food may have played a role. People may also have changed their food intake, using less vegetables, due to fear of these being polluted by radioactive fallout.

Accidents↗

Serologic markers for hepatitis B among Marshallese accidentally exposed to fallout radiation in 1954.

At least one serologic marker of prior hepatitis B infection (hepatitis B surface antigen, antibody to surface antigen, or antibody to core antigen) was found in 91.7% of 314 Marshallese tested. The prevalence of hepatitis B surface antigenemia (3.3%) in a subpopulation that had resided on Rongelap Atoll at the time of accidental exposure to radioactive fallout from a thermonuclear test in 1954 did not differ significantly from the prevalence in a selected unexposed population (10.5%).

Adolescent↗

The accident at Chernobyl and trisomy 21 in Finland.

Our objective was to explore whether the radiation fallout in Finland after the accident at the Chernobyl nuclear power plant in April 1986 led to an increased incidence of trisomy 21. In this geographic and temporal cohort study, the country was divided into three zones according to the amounts of radioactive fallout and internal radiation caused by two cesium isotopes. The 518 cytologically verified cases of trisomy 21 were divided into a control group (conceived before the accident), and a study group of children whose expected dates of birth were in the post-accident years 1987-1988, i.e., pregnancies commenced after May 1986. The cases were also divided into three subgroups according to the zones of radiation. There were no significant differences in prevalence of trisomy 21 between the control and study groups nor between the three zones in spite of the significant differences in the levels of radiation and in the body burden that prevailed throughout the study period. Power estimates showed that in the two zones of lower radiation, an increase of 0.5% in the prevalence would have been detected with a power of 0.85, and in the somewhat smaller zone of the highest radiation, with a power of 0.70. The study lends no further support to the view that the low radiation fallout in western Europe would have been causally associated with trisomy 21.

Accidents↗

Radiation accidents.

It is essential that emergency physicians understand ways to manage patients contaminated by radioactive materials and/or exposed to external radiation sources. Contamination accidents require careful surveys to identify the metabolic pathway of the radionuclides to guide prognosis and treatment. The level of treatment required will depend on careful surveys and meticulous decontamination. There is no specific therapy for the acute radiation syndrome. Prophylactic antibodies are desirable. For severely exposed patients treatment is similar to the supportive care given to patients undergoing organ transplantation. For high-dose extremity injury, no methods have been developed to reverse the fibrosing endarteritis that eventually leads to tissue death so frequently found with this type of injury. Although the Three Mile Island episode of March 1979 created tremendous public concern, there were no radiation injuries. The contamination outside the reactor building and the release of radioiodine were negligible. The accidental fuel element meltdown at Chernobyl, USSR, resulted in many cases of acute radiation syndrome. More than 100,000 people were exposed to high levels of radioactive fallout. The general principles outlined here are applicable to accidents of that degree of severity.

Bone Marrow Transplantation↗

Recent research involving the transfer of radionuclides to milk.

The radionuclides in milk, which result from exposure of dairy cows to radioactive fallout, are a major factor in assessment of internal radiation of humans. To evaluate the radionuclide intake of people from fallout-contaminated milk requires information about feed sources and milk distribution. Pasture intake and the shelf-life of milk are important factors in the case of a short-lived radionuclide like 131I. Large-scale human radiation assessment studies are underway, all of which consider the dairy food chain as a critical component. These include retrospective studies of fallout from nuclear weapons testing at the Nevada site in the 1950s and the impact of the Chernobyl accident on April 26, 1986.

Accidents↗

Transfer factor of 131I from the fallout to human thyroid dose equivalent after the Chernobyl accident.

A similar pattern of variation with time in observed maxima of daily dose equivalent rates in human thyroids (TD - microSv.d-1) and of daily fallout radioactivities (FR - kBq.m-2) has been found after the Chernobyl accident. An estimate of the time-lag between the maxima in TD lines and the preceding FR peaks was made of about seven days for adult and nine days for juveniles. Applying this time-lag it was possible to estimate transfer factors from the fallout to thyroid dose equivalent: the highest estimated values were 221 microSv/kBq.m-2 for adult and 641 microSv/kBq.m-2 for juvenile thyroids. These values differ from those published by UNSCEAR (United Nations 1988), which have been calculated for various regions of Czechoslovakia, from ingestion and inhalation intake estimates. A broad variation of transfer factor values could be expected to result from such transfer calculations using ingestion and inhalation estimates. The findings also support the concept of a need for prolonged iodine prophylaxy after emissions of radioiodine into the environment.

Accidents↗

Cancer incidence among Sami in Northern Finland, 1979-1998.

The Sami population living in Northern Finland represents a specific genetic background and a way of life that is different from other Finns. A cohort of 2,100 Sami and 4,174 non-Sami people from the 2 northernmost municipalities of Finland on 31 December 1978 was identified from the national Population Register and followed up through the Finnish Cancer Registry for cancer incidence during 1979-1998. There were 111 cancer cases among the Sami, while the expected number based on the average cancer incidence in the Finnish population was 173. Among the non-Sami cohort members, there were 226 cases of cancer vs. 224 expected cases. The Sami had significantly decreased incidence of cancers of the prostate [standardised incidence ratio (SIR) 0.25; 95% confidence interval (CI) 0.08-0.58] and breast (SIR 0.36; 95% CI 0.14-0.73), similarly for both localised and nonlocalised tumours. Low SIRs were also observed for bladder cancer (SIR 0.28; 97% CI 0.03-0.99) basal cell carcinoma of the skin (SIR 0.12; 95% CI 0.03-0.30) and other nonmelanoma skin cancers (SIR 0; 95% CI 0-0.63). In contrast to other subcategories of the Sami, the Skolts, whose lifestyle stems from areas that now belong to Russia, showed a nonreduced overall cancer risk and a significantly elevated risk for stomach cancer (SIR 3.8; 95% CI 1.5-7.8). The low cancer incidence among the other Sami populations in Finland cannot be fully explained by their specific way of life. It seems likely that the Sami ethnicity carries a reduced cancer incidence level. Although many Sami have been exposed to radioactive fallout from the nuclear weapon tests via their reindeer-rich diet, this does not seem to affect their cancer risk.

Feeding Behavior↗

Laboratory analyses: environmental and biological measurements.

From its inception in 1951 to the present, the measurement of radioactive fallout from nuclear weapons testing and the many associated programs to establish global distribution and human health effects have contributed significantly to the understanding of worldwide dispersal of contamination. The original measurements of regional surface deposition of fallout nuclides were with duplicate gummed film collectors. Later, collectors were established in a worldwide network to measure total deposition and specific radionuclides such as 90Sr and 137Cs, which evolved into the first large-scale, global environmental monitoring network. Programs were set up to determine dietary intake and human and animal tissue distribution of 90Sr and 137Cs. Some of the first measurements of natural background dietary radium and body potassium were a response to identify analog elements. The impact of the environmental measurements made for fallout went far beyond any dosimetric consequences. For example, present day information on bone tissue turnover rates are derived mainly from radiochemical analysis of 90Sr measurements in human bone. The spin off from the enormous expenditure in effort to make these measurements and to determine the health consequences of global fallout laid a rich basic and applied scientific foundation in many disciplines, particularly in exposure pathways from ground deposition to dietary uptake and human organ biokinetics.

Environmental Monitoring↗

External dose estimates for Dolon village: application of the U.S./Russian joint methodology.

Methods to estimate external dose from radioactive fallout from nuclear tests have for many years depended on two types of data: measurements of exposure rate in air and an empirically derived power function to describe the change in exposure rate with time, Over the last four years, a working group with American and Russian participation has developed a bi-national joint methodology that offers an improved capability for estimating external dose. In this method, external dose is estimated using exposure rate functions derived from data from American nuclear tests similar in construction to SNTS (Semipalatinsk Nuclear Test Site) devices. For example, in this paper, we derive doses for test #1 (August 29, 1949) at the SNTS using an exposure rate function for the U.S. TRINITY test. For the case of test #1, the average external dose for a person in Dolon is estimated to have been about 0.5 Gy compared to 1 to 2 Gy estimated in other work. This prediction agrees better with reported EPR measurements in teeth from village residents and with measurements of TL signals in bricks from Dolon buildings. This report presents the basic elements of the joint methodology model for estimation of external dose received from SNTS fallout.

Body Burden↗

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↗

The controversy over radiation safety. A historical overview.

The hazards of ionizing radiation have aroused concern since a short time after the discovery of x-rays and natural radioactivity in the 1890s. Misuse of x-rays and radium prompted efforts to encourage radiation safety and to set limits on exposure, culminating in the first recommended "tolerance doses" in 1934. After World War II, the problems of radiation protection became more complex because of the growing number of people subjected to radiation injury and the creation of radioactive elements that had never existed before the achievement of atomic fission. Judging the hazards of radiation became a matter of spirited controversy. Major public debates over the dangers of radioactive fallout from atmospheric bomb testing in the 1950s and early 1960s and the risks of nuclear power generation in later periods focused attention on the uncertainties about the consequences of exposure to low-level radiation and the difficulties of resolving them.

Environmental Exposure↗

Myelodysplastic syndrome in two young brothers.

We report the youngest cases of myelodysplastic syndrome (MDS) in two brothers aged 7 and 2 years. The maternal grandfather and maternal grandmother had been exposed to radioactive fallout after the atomic bomb attack on Hiroshima in 1945. The elder brother demonstrated pancytopenia with < 1% blast cells in his peripheral blood and < 5% in his bone marrow at diagnosis. The younger brother was thrombocytopenic without increased blasts. The karyotype of bone marrow cells from the elder brother was 46,XY, -7, +der (7), t(1:7) (lqter-lq11::7q11-7pter), but the younger brother's karyotype was normal. Immature myeloid cells in the bone marrow from both brothers were morphologically abnormal. A diagnosis of refractory anaemia (RA) was made in both brothers. Atavism due to radioactive poisoning was suspected in the development of MDS in these two cases.

Anemia, Refractory↗

Overview of the Department of Energy's Off-Site Radiation Exposure Review Project (ORERP).

The Off-Site Radiation Exposure Review Project (ORERP) was established by the U.S. Department of Energy to (1) collect, preserve, and disseminate historical data related to radioactive fallout and health effects from nuclear testing, and (2) reconstrut, insofar as possible, the exposures to the off-site public from nuclear testing at the Nevada Test Site and doses to individuals resulting from these exposures. The goals, methods, and example results of the ORERP are presented.

Archives↗

Chernobyl retrospective.

On April 28, 1986 heavy radioactive fallout from an unknown source was reported from Sweden. Later, it was discovered that two days earlier, a nuclear power reactor at Chernobyl, in the Soviet Union, had exploded releasing an enormous cloud of effluent containing 40 million Ci of 131I, 3 million Ci of 137Cs, and 50 million Ci of xenon radioisotopes. This far exceeded the 15 Ci of 131I escape in the notorious Three Mile Island accident. Chernobyl reactor IV, of an antiquated design, was a graphite-moderated reactor which suffered a steam explosion when the operating staff attempted an experiment involving preservation of safety functions during a planned shutdown. Following the explosion, a fire started in the graphite core which required ten days to control. Thirty-one persons died, two in the initial explosion and 29 of various combinations of thermal and radiation burns, and gamma irradiation. Existing emergency plans were invoked involving treatment on the scene and evacuation of seriously injured patients to a special hospital in Moscow, as well as to nearby Kiev. Later, 135,000 residents of the immediate neighborhood were surveyed and evacuated after fallout radiation levels began to rise. Fallout patterns around Europe and the northern hemisphere were closely tracked. Consequences of the accident in human and monetary terms will require years of evaluation. Although the United States has no power reactors of the Chernobyl type, the country does have a radiation disaster management plan, often rehearsed at the state level. As a consequence of Chernobyl certain international agreements dealing with radiation disaster information and management have been forged.

Accidents↗

Thyroid cancer has increased in the adult populations of countries moderately affected by Chernobyl fallout.

BACKGROUND: The incidence of thyroid carcinoma increased among children affected by Chernobyl fallout. Less evidence exists for a corresponding effect in adolescents and adults. The Cancer Registry of the Czech Republic provides an opportunity to study various determinants of the occurrence of thyroid cancer. MATERIAL/METHODS: Anonymous population-based incidence data on thyroid carcinoma of the Czech Republic from 1976 to 1999 were obtained from the Czech Statistical Office (CSO) and the Institute of Health Information and Statistics (IHIS). This study covers 247 million person-years. Linear logistic regression models allowing for possible changes in slope (change-points) are suggested for the trends of incidence proportions. RESULTS: From 1976 to 1999 a uniform annual increase of 2.0% per year was found in the directly age-standardized thyroid cancer incidence proportion (95%-CI: 1.3-2.7, p<0.0001). From 1990 on, we observed an additional significant increase in the thyroid cancer incidence of 2.6% per year (95%-CI:1.2-4.1, p=0.0003). This effect (change-point) is essentially independent of age but dependent on gender: females 2.9% per year (95%-CI: 1.3-4.7, p=0.0006), males 1.8% per year (95%-CI: -1.0-4.7,p=0.2127). The estimated minimum latency period for the population as a whole is 4 years. CONCLUSIONS: Although the Czech Republic received only a relatively moderate amount of radioactive fallout,an unexpected uniformly accelerated increase of thyroid cancer in all age categories is seen from 1990 onwards. Therefore one should look carefully at collective dose and at the group of persons low in individual organ dose but high in number.

Adolescent↗