The paper deals with one of the most urgent aspects of irradiation hygiene, namely assessment of risk for irradiation-induced cancers of the thyroid. A model is described to predict high mortality rates of thyroidal cancer in the population due to the catastrophe at the Chernobyl Atomic Power Station. With the model, life-time risk rates involving sex and age at the moment of irradiation, as well as an irradiation mode.
In Norway, external doses of radiation resulting from fallout from the Chernobyl nuclear accident were estimated from detailed measurements, including soil deposition patterns. Internal doses were estimated from measurements of radioactive cesium in meat and milk supplies. The doses were calculated as average monthly doses for each of 454 municipalities during 36 consecutive months after the accident in spring 1986. Prospectively collected data on all newborns listed in the Medical Birth Registry of Norway who were conceived in the period May 1983-April 1989 were used to assess possible dose-response relations between estimated external and food-based exposures and congenital malformations and some other conditions. A positive association was observed between total radiation dose (external plus food-based) and hydrocephaly, while a negative association was observed for Down's syndrome. However, an important conclusion of the study was that no associations were found for conditions previously reported to be associated with radiation, i.e., small head circumference, congenital cataracts, anencephaly, spina bifida, and low birth weight. Potential sources of bias, including exposure misclassification and incomplete ascertainment of cases, are discussed.
The estimation of the effective dose equivalents of exposure to accidental and non-accidental sources was made on the basis of the studying of radiation situation variations in Kiev after the Chernobyl accident in 1986-1989. The total annual effective dose equivalents to the Kiev population from all sources of exposure for 1986-1989 were 9.19, 7.29, 5.34 and 5.03 mSv, respectively. The necessity of radiation health measures aimed at limiting the intake of long-acting radionuclides of Chernobyl nature and reducing the exposure doses by optimizing the x-ray procedure and by regulating the natural radioactivity of building materials are under discussion.
This article describes the nutritional measures introduced to protect health after the Chernobyl accident, and the associated costs. The total value of the reindeer meat, mutton, lamb and goat meat saved as a result of such measures in 1987 amounted to approx. NOK 250 million. The measures cost approx. NOK 60 million. The resulting reduction in the radiation dose level to which the population was exposed was 450 manSv. In 1988, mutton/lamb and goat meat valued at approx. NOK 310 million was saved from condemnation by similar measures, which cost approx. NOK 50 million. The resulting dose level reduction was approx. 200 manSv. The relationship (cost/benefit ratio) between the overall cost of the measures taken to reduce radioactivity levels in food and the dose level reduction achieved was acceptable.
The paper considers the radiation doses of the thyroid gland in the inhabitants from the Ukrainian SSR areas (Kiev, Zhitomir, Chernigov, and Vinnitsa Regions), which have been obtained by instrumental studies of thyroidal radioactivity in May-June, 1986, and calculated by the most conservative single-dose administration model. A hygienic evaluation has been made of the findings, taking into account the age and residence. The cumulative irradiation doses of the thyroid have been estimated for children and adults. Possible late sequelae for the areas in question may account for 1060 and 300 thyroid carcinoma cases during the whole life for children and adults, respectively.
This paper describes the findings of the radiation situation analysis on-site near Sysoeva and Razbojnik Bays. The results of radiation monitoring performed by radiological laboratory of DalRAO and studies performed by the experts from the Burnasyan Federal Medical Biophysical Centre have been used in the course of analysis. On the industrial sites, gamma dose rate reaches 60 µSv h(-1), and the specific activities of man-made radionuclides in soil reach 2.5 × 10(4) Bq kg(-1) for (137)Cs, 7.6 × 10(3) Bq kg(-1) for (90)Sr and 2.0 × 10(3) Bq kg(-1) for (60)Co. Beyond the industrial sites, there are three local parts of the area on the coast and in the off-shore water area, contaminated with man-made radionuclides. Gamma dose rate reaches 8 µSv h(-1). The radionuclide contents in soil at this area reach 3.6 × 10(3), 2.8 × 10(3) and 19 Bq kg(-1) for (137)?s, (90)Sr and (60)??, respectively. At the remaining part of the area nearby Sysoeva Bay, the radiation situation complies with natural background.
Pregnancy outcome has been studied in terms of legal abortions, early spontaneous abortions and total number of pregnancies (in an ad hoc study covering 6 counties) as well as various perinatal health problems (on the basis of routinely recorded data for epidemiological surveillance from the Medical Birth Registry of Norway). Apparently, no effects were observed in terms of an increased occurrence of legal abortions, while spontaneous abortions increased from 7.2% of all pregnancies during the last 12 months before the accident to 8.3% after the accident [corrected]. At the same time, the total number of pregnancies somewhat decreased. Based on monthly measurements in each municipality of external and internal (food-based) doses, dose-response associations were assessed for a number of perinatal health problems. No associations were observed.
Accidents and disasters involving ionizing radiation are rare. Such accidents may occur not only at nuclear power stations but also in medicine and in industry. Only fairly large radiation doses can give acute medical effects. Symptoms and signs depend on the actual dose, and on what parts of the body are irradiated. In connection with a radiation accident, the main points are to recognize in the first place that radiation may be involved, and to have some knowledge of the actual source. Risk of localized irradiation from industrial sources, especially of hands, is a problem that is often overlooked. The paper reviews the principles for action by local health officers, the pathogenesis of radiation injury and early medical management. Some information is also given on the Norwegian system of contingency preparedness against nuclear accidents.
The data on the assessment of the radiobiological situation and the results of clinical and epidemiological studies into the population health status, exposed to radiation because of the Chernobyl NPP accident are summarized. Appropriate regularities in soil contamination with 137Cs are ascertained. It has been shown that the disease incidence among the children's and adult population of the controlled areas is associated not only with improvement of the disease revealing but with the influence of the accident consequences.