This report examines the claim that Irish mortality in the second quarter (April-June) of 1986 increased due to the cloud of radioactive material released by the damaged reactor in Chernobyl. Over the period 1971-1987, based on date of registration, the death rates in the second quarter showed marked year to year variation often exceeding that expected on the basis of chance alone. In 1986 the percentage of annual deaths occurring between April and June, and the death rate itself, were both significantly higher than in most other years between 1981 and 1987. The 1986 figures were not however, significantly higher than those observed in years prior to 1981. Since the distribution of mortality by cause was not consistent with the hypothesis relating low level radiation to immediate mortality, and since causality cannot be inferred from a temporal association per se, the Chernobyl accident cannot be implicated in the excess mortality observed in the second quarter of 1986.
A selected group of about 20 male researchers at the NIRS that reside in Chiba, Japan, was measured for total body content of radiocesium and 40K every 3 mo from February 1986 to May 1991. A whole-body counter at the NIRS was used to measure their radioactivity in a scanning mode of 5 cm min-1 in a shielded iron room with walls 20 cm in thickness. A maximum radiocesium level of 59 Bq was observed in May 1987. The annual change in the body burden decreased with an apparent half-time of 1.8 y after May 1987. The period of five years was sufficient to eliminate the effects of the accident in this group. Even in the most contaminated period, the dose from radiocesium was below 2 microSv y-1. The cumulative dose for 5 y was estimated to be 5.6 microSv, which is nearly equal to the total dose to the Japanese people caused by the artificial radionuclide fallout for the first year following the accident. It is much smaller than the committed dose of 82 microSv for internally deposited 137Cs resulting from nuclear explosions in 1961 and 1962 and the annual dose of 170 microSv from internal 40K. No detectable health risk was expected for the present group.
The children living in 4 regions of Russia contaminated as a result of the Chernobyl catastrophe were investigated. The control group consisted of the children of 2 regions which did not undergo this influence. The investigations were made 1-3 years after the catastrophe took place. An increase of etiologically non-clear asthenic-vegetative disorders was determined in the regions of radiation contamination. They were observed mainly among the children who had light residual organic cerebral deficiency. The authors cannot exclude the impact of the psychogenic factors.
The aim of the present study was the observation of the frequency of antithyroid autoantibodies in the population in low endemic goitre area after mass iodine prophylaxis after the Chernobyl catastrophe and the estimation of TSH and thyroid hormones secretion in this population. On the basis of the investigations carried out we could conclude that the frequency of antithyroid autoantibodies in the population with confirmed endemic goitre is comparable to the frequency of antithyroid autoantibodies in the healthy population. ATA occurrence in children after iodine prophylaxis could confirm the hypothesis that thyroglobulin immunity is higher after iodine intake. The lower T3 concentration observed in the group with antithyroid autoantibodies suggests that autoantibodies may be involved in the thyroid hormones synthesis or peripheral conversion of thyroid hormones.
The course of 137Cs content of children after the reactor accident of Chernobyl measured by means of a whole-body counter could be reconstructed theoretically by a pharmacokinetic model. The children of the kindergarten of the hospital of the University of Cologne accumulated during the vegetation periods 1986/87 (I) 86.9, 1987/88 (II) 114.4 and 1988/89 (III) 24.4 Bq 137Cs per kg body weight.
Current doses arising from external and internal pathways have been estimated for the residents of two villages, Muslumovo and Brodokalmak, alongside the Techa River, which was contaminated by radioactive releases from the Mayak production facility. The dose estimates are based on numerous environmental measurements supplemented by further human whole body measurements and studies on occupational and dietary habits of Slavic and Turkish ethnic groups. Estimated doses arise mainly from use of the contaminated floodplains alongside the Techa River. The current average annual effective dose attributable to Cs and Sr in the environment, under conditions where restrictions on some river-related activities are in place, may exceed the Russian national action level of 1 mSv only in the hypothetical critical group of herdsmen in Muslumovo. The dose to this critical group in Brodokalmak is assessed to be 3 times less than that in Muslumovo and 2 fold below the action level. The external and internal exposures give comparable contributions to the total dose in both settlements and population groups: 47% and 53% in Muslumovo and 40% and 60% in Brodokalmak, respectively. About one quarter to one half of the internal dose in adults arises from the intake of Sr. In order to avoid substantial increases in the dose received by Muslumovo residents, it is expedient to prolong the current policy of restriction of some river-related population activities in this village.
Residents of Vienna, Austria were whole-body counted for radiocesium content due to fallout deposited after the Chernobyl accident. Data for a 2-y period were compared with prior estimates of radiocesium body burden based on food consumption. Our results suggest that the prior estimates be revised and the rejection limit be increased by a factor of 2 for contaminated food.
The qualitative and quantitative parameters of hemopoiesis and immunocompetent cells were studied in 365 children in the early "iodine" and long-term periods after the accident. In accordance with primary response, a group consisting of 28 subjects with so-called "radiation injury" was distinguished. The early period was marked by unusual qualitative and quantitative hematological changes which, however, did not lead to the development of the hematological syndrome characteristic of acute radiation injury. Certain deviations that corresponded to somatic pathology were detectable at the late periods after the accident.
It was attempted to assess the incidence of thyroid diseases in Polish children born between 1980-1986, who at the time of the Chernobyl nuclear disaster were 0-6 years old, or whose mothers were in the third trimester of pregnancy. 3071 children have been examined, 1772 girls and 1299 boys. The following were assessed in each child: the health status, the developmental level, the thyroid ultrasound examination, and the level of TSH, FT4, antithyroid antibodies ATM and ATGL in the blood serum. Disorders in thyroid morphology (abnormal echogenicity) have been found in 462 children (15%), almost twice as much in girls than in boys. Goiter has been recognized in 4.6% of all children, an abnormal echogenity in 5.4% and focal changes in 4.8%. 3.9% of children have been found to have a high level of ATM antibodies, and 8.7%--a high level of ATGL antibodies. Among 6 children, who had thyroidectomy, 2 children have been diagnosed to have ca papillary and 4 children--adenoma.
The results of experimental studies on the repeated exposure to radioiodine (131I) and nuclear fission products (NFP) are presented, the doses used being equal to those resulted in radiation disease under first and second input. The animals satisfactory withstood the repeated exposure. The residual injuries appeared slightly. The animals' state was satisfactory during 5 years. Blastomogenic effect of NFP was revealed in remote periods.