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 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.
Incidence of and mortality from cardiovascular diseases have been studied in a cohort of 12,210 workers first employed at one of the main plants of the Mayak nuclear facility during 1948-1958 and followed up to 31 December 2000. Information on external gamma-ray doses is available for virtually all of these workers (99.9%); the mean total gamma-ray dose (+/-SD) was 0.91 +/- 0.95 Gy (99% percentile 3.9 Gy) for men and 0.65 +/- 0.75 Gy (99% percentile 2.99 Gy) for women. In contrast, plutonium body burden was measured for only 30.0% of workers; among those monitored, the mean cumulative liver dose from plutonium alpha exposure (+/- SD) was 0.40 +/- 1.15 Gy (99% percentile 5.88 Gy) for men and 0.81 +/- 4.60 Gy (99% percentile 15.95 Gy) for women. A total of 3751 cases of ischemic heart disease (IHD), including 683 cases of acute myocardial infarction (AMI), and 1495 IHD deaths, including 338 AMI deaths, were identified in the study cohort during the follow-up period. Having adjusted for non-radiation factors, there were statistically significant increasing trends with both total external gamma-ray dose and internal liver dose in IHD incidence. The trend with internal dose was weaker and was not statistically significant after adjusting for external dose, whereas the external dose trend was little changed after adjusting for internal dose. The trend with external dose in IHD mortality was not statistically significantly greater than zero but was consistent with the corresponding trend in IHD incidence. The estimated trend in IHD mortality with internal dose was lower and was not statistically significant once adjustment was made for external dose. There was a statistically significantly increasing trend in AMI incidence but not AMI incidence with external dose. The risk estimates for IHD in relation to external radiation are generally compatible with those from other large occupational studies and the Japanese A-bomb survivors.
The results of dosimetric evaluations carried out after Chernobyl accident in the Health Physics Department of Niguarda Ca' Granda Hospital (Milan) on air, rain and ground contamination are presented. The results obtained show that the incidence of stochastic late effects, both somatic and genetic, will be so low that practically will not be distinguishable from "natural" incidence.
Erratum In: Radiol Med (Torino) 1986 Dec;72(12):986
I had originally thought that by this time, nearly 1 year after the Chernobyl reactor accident, I would be in a position to describe fully its impact on the UK in terms of radiation doses, economics and future emergency planning. However, only one of these is reasonably clear-the radiological impact. We shall continue our measurements, particularly those of activity in persons, and doubtless we shall refine our estimates of collective dose, but they are unlikely to change significantly. We can therefore be certain that the radiological impact on the UK was small and that the health effects will not be detectable. Predictions of the consequences of accidental releases of radionuclides have in the past, perforce, relied upon models of environmental transfer. Data on which the models are based were obtained from investigations of weapons fallout and of routine releases from nuclear facilities. The Chernobyl accident provided a situation of activity deposition that was well characterised in time and in geographical distribution, and measurements along environmental pathways will allow us to validate or refine our models. This accidental deposition reinforced the importance of some effects that we knew about-such as the importance of wet deposition-and will cause us to consider the need to take account of specific situations that we had not considered previously in adequate detail-in particular, the behaviour of radionuclides in upland ecosystems. The overall economic impact is not yet clear and, unfortunately, is unlikely to become so until all restrictions on the movement and slaughter of sheep are removed and the farmers have received compensation. The effect on international trade may never be quantified. Some international agencies are evaluating the consequences of Chernobyl and their reports will become available during 1987. International agreements on intervention levels are also still under discussion and it would be premature to speculate about the need for any fundamental revisions to Emergency Reference Levels and derived quantities. Similarly, we are aware of the need for revision of the national emergency plan, but we are awaiting the government decision on this. One effect of the Chernobyl accident, however, is clear: the public's awareness of radiation issues has reached a new height. Members of the public demand information and advice, and better means of communicating these must be provided. Advice to take some action may provoke unnecessary alarm, but advice that no action is required may be distrusted. We cautiously assume that any dose, no matter how small, has some deleterious effect and yet, in situations of accidental releases, we may tell the public that no actions are required to reduced doses that they may consider appreciable and avoidable. We clearly need to promote a better understanding of the nature and acceptability of the risk of radiation doses in such circumstances and we intend to do so.