Medical effects of the Chornobyl catastrophe: what is known in 19 years?
Scientific Center of Radiation Medicine, AMS of Ukraine
About 4 million people were exposed as a result of the Chornobyl catastrophe. The evidential data regarding medical consequences of the catastrophe for various categories of the affected people that have been obtained during 19 years after the accident may be generalized in the following way.
Acute radiation syndrome (ARS).
237 patients had ARS in 1986. 134 cases were verified in 1989. During the first 90 days of 1986, 28 people died; 29 passed away during 1987-2005. Currently, 164 ARS-patients are being monitored at the SCRM (88 – non-verified ARS cases and 76 – verified). Causes of deaths: sudden heart death (8), onco-hematology and oncology (11), somato-neurological diseases, infections (6), traumas and accidents (4). Radiation damages to skin. There were 2 cases of thyroid cancer in 2000 (ARS-II). 24 ARS patients have radiation cataract proportionally to their dose. Vascular disease of eye fundus and macular dystrophy. Cardiovascular diseases are the most frequent. In 1986-1987, radiation-induced immunodeficiency with current formation of steady remote effects. All have organic mental disorders mostly in the form of edoform (apathy) psychoorganic syndrome. 62% have post-radiation organic disorders (with doses >1 Sv). Neurophysiological and neurovisualization radiation markers with doses of 1-5 Sv.
Total number is ~600,000; ~364,000 – in Ukraine. Average effective dose of the ChNPP accident consequences liquidators’ (ACL) external exposure amounts to the following: 163.7 mSv for 1986-1987 ACL and 45.8 mSv for 1988-1989 ACL. Deterioration of health almost for all classes of diseases. Anticipated increase in a number of thyroid cancer cases. There is a tendency of increased leucaemia among ACL of 1986-1987, as well as of solid tumours. Increased disablement. Increase in non-oncology diseases, including mental disorders. Radiation risks for non-cancer diseases (0.25-0.5 Sv and more): cerbrovascular diseases, mental disorders, neuropathies, endocrinal diseases, etc. The hypothesis that there is a non-threshold development of cataract and other eye diseases. Prevalence of mental disorders (36%) is almost 2 times as high as among the Ukrainian population (20.5%), mainly due to depression (25%). There is a dramatic increase in suicides (as per some assessments: 20 times more if compared to general population). “Dose-effect” dependencies were obtained for neurophysiological, neuropsychological, neurovisualization parameters, and doses >300 mSv. Small and very small doses – chronic fatigue syndrome. Radiosensitivity of brain. Radiosensitivity of neocortex is higher that the one of subcortical formations and brain trunk. Radiosensitivity of dominant hemisphere is higher. Presence of deterministic neuropsychiatry effects with the threshold of 300 mSv of general exposure.
Absolute deterioration of demographic situation. However, only in some cases indexes of infant mortality observed within the contaminated areas were higher than those of ‘clean’ areas. Dramatic increase of thyroid cancer cases among those, who were exposed in childhood (0-14 years). No reliable data regarding increase of leukemia, lymphoma, other forms of solid cancers were obtained. A vivid tendency towards lagging physical development of children from radioactively contaminated areas was discovered. Reduced head size was found out in children from Belarus radioactively contaminated areas. Deterioration of somatic and mental health in all classes of diseases, particularly, thyroid diseases, defective regulation of immune, endocrine, and nervous systems. Discrepant data regarding congenital malformations, genetic effects (including children of the liquidators) and hereditary diseases, deteriorated health of the liquidators’ children. Availability of information about increase of Down’s syndrome in 1987 (mentally and physically backward children as a result of the 21-st chromosome congenital trisomy) in Sweden, West Berlin, Scotland, and Belarus (January 1987). Lack of dairy and meat products, fruit and vegetables, i.e. shortage of protein, vitamins, macro- and microelements. Formation of a ‘victim’ social and psychological complex.
In utero exposed children (born between April 26, 1986 and February 26, 1987)
More neuropathies and mental disorders were revealed. The exposed children showed lower full-scale IQ due to lower verbal IQ, and therefore an increased frequency of performance/verbal intelligence discrepancies. When IQ discrepancies of the in utero exposed children exceeded 25 points, there appeared to be a correlation with the fetal dose. Neurophysiological markers of radiation effects with prenatal exposure and with in utero thyroid doses amounting to >300 mSv. The exposed and control mothers did not show differences in verbal abilities, but the evacuated mothers have experienced much more real stress and have more depression, PTSD, somatoform disorders, anxiety/insomnia, and social dysfunction, than the control mothers from Kyiv. Risk of spontaneous abortions during the 1-12-th weeks of gestation period at the moment of exposure and with doses of >5 mSv.
Tendency towards increase of solid tumour diseases. Increase in neo-oncology diagnoses for practically all classes of diseases including mental disorders (depressions, PTSD, somatoform disorders, anxiety, insomnia, social dysfunction). People evacuated from Pripyat showed the highest level of diseases (especially women). Impacts of whole-body exposure and thyroid exposure effects were traced.
Dramatic increase of radiation-induced thyroid cancer (especially in the age of 0-18 at the moment of the accident). There is also some increase in mammary gland cancer. Increase in renal-cellular epithelial tumours. There are no reliable data regarding increase in radiation-induced leucaemias, though the data are discrepant. Also, no data on radiogenic gastric, intestine, and lung cancers were obtained. Deteriorated health, decrease of childbirth, increase in abnormal pregnancies. Anxious, stress-related psychosomatic disorders.
International experts of the ‘Chornobyl Forum’ (IAEA, WHO, etc.) have highlighted the following urgent medical problems of Chornobyl:
- Thyroid cancer and other thyroid pathologies
- Other, excluding thyroid cancer, solid cancers
- Non-cancer and non-thyroid effects:
- Mortality attributed to the Chornobyl NPP accident
- Psychic and psychological aftermath and effects in the central nervous system
- Reproductive effects and children’s health
- Cardiovascular diseases
- Immunology effect
Health protection programs in Belarus, Russian Federation, Ukraine.
Chornobyl impact on mental health is the severest among current medical and social problems. The major problems include:
- Stress-related symptoms
- Radiation effects onto developing brain
- Organic damage of brain of the liquidators, who were subject to significant exposure
- Suicides of the liquidators, who were subject to significant exposure.
Bogdan Serdiuk, Chornobyl NPP
Social issues faced by Slavutych people after Chornobyl accident and ChNPP closure
As a result of the Chornobyl accident, large territories were subjected to radiation contamination. The population has experienced a set of negative consequences: radiation contamination, psychological stress, and evacuation.
Hundreds of thousands of people have been evacuated from the most affected areas. Because of insufficient financing, 814 families still continue their living in the zone of absolute resettlement. Budget financing of the Chornobyl programs provides only for their 17% implementation.
According to the data provided by the committee of liquidators, 94.2% of people, who participated in eliminating the Chornobyl accident, are considered to be ill, but for all that the budget of Ukraine provides only $2.5 for the treatment of one liquidator.
During the last 10 years, a number of disabled among the liquidators has grown twice, and a number of people, who died as a result of contamination, ranges approximately from 10 tо 100 thousand people as per various assessments.
Social programs to mitigate the accident consequences have been approved by the Law on the Status of People Affected as a Result of the Chornobyl Catastrophe. Benefits for the affected by the Chornobyl catastrophe cover many aspects of life: health service, living conditions, free fare, taxation benefits, compensations for property damage, and compensations for health loss caused by the Chornobyl catastrophe.
However, although the amount of financing was approved by the parliament, the affected get a rather reduced assistance. For example, 17.5 thousand of Slavutych residents have status of people affected by the Chornobyl catastrophe. Last year, UAH 290,000 were received to buy medicine. It is approximately 25% per month for 1 individual.
Only 279 sanatoriums vouchers were allocated, though a number of people, who need them, is over 6,000. Price of a voucher is high enough for the affected people to buy it at his own cost – about UAH 2,000; and compensation for a non-used voucher is only UAH 58. However, even such a compensation has not been paid for 2 years.
An anxiety about an unpredictable health effects of radiation is among social consequences of the catastrophe. After closing the ChNPP, a pressure of uncertainty in the future added to the anxiety of Slavutych people.
Meeting its liabilities under the international treaty, Ukraine has stopped the ChNPP operation on December 15, 2000.
Thanks to adoption of a proper legislative norms, social consequences of the ChNPP closure were smoothed over. According to the legislation, the dismissed workers get a substantial financial compensation, but establishment of the special economic zone in Slavutych with a favorable tax climate for business development was the main achievement. It enhanced development of private enterprises and creation of new jobs. And though one third of the plant employees have lost their jobs, the official level of unemployment in the town is only 4.5%. This year the government decreed a moratorium for special economic zones, however we hope that our case will be revised, taking into consideration the abovementioned problems with state financing of Chornobyl programs.
Boris Oskolkov, Chornobyl Center
Major ecological consequences of Chornobyl catastrophe
The Chornobyl catastrophe does not have any analogues in terms of radioactive contamination area and amount of plants, animals, and people radiation exposure. Due to their high mobility and high energy of radiation spectrum, radioactive isotopes of iodine, strontium, cesium, plutonium are the most dangerous for every living being. Because of meteorological conditions, during the first 10 days after the accident the contamination of the area was heterogeneous, «spotty», therefore the level of radiation doses received by living beings differed by a factor of ten or hundred times even on small areas.
Natural and agrarian ecological systems within the 30-km Chornobyl zone undergone the strongest radiation influence.
The Chornobyl catastrophe happened at the end of April, i.e. in the period of plants and soil inhabitants’ rapid growth. And this period is the most radiosensitive for them. The maximum radiation impact on living beings was during the first 10-20 days since the moment of accident. The second phase included summer and early autumn of 1986, when intensity of radiation dose on the soil surface decreased to 20-25% of the initial quantity.
In 1986-1988, numerous facts of plants and animals’ radiation damage were found within the 30-km Chornobyl zone. Thus, it was possible to observe considerable, never seen in nature before, damages of ecosystems within the Chornobyl exclusion zone, though not on large territories. So, destruction of pine forests was fixed within the area of approximately 500 hectares (later called “red forest”) in immediate proximity to the ChNPP. A total damage of soil invertebrates was fixed within the same area and signs of changes in population indexes in mouse like rodents were observed there later. However, the most considerable changes of ecological system within this area are connected not with radiation damage of the organisms, but with a human leaving. As it is well-known, the population has been evacuated from the area later called the Chornobyl exclusion zone because of the high levels of radiation contamination. Practically, the evacuation of inhabitants from all built-up areas subjected to the contamination began immediately after the accident, on the 27-th of April. Totally, 90,784 individuals from 81 Ukrainian villages and towns were evacuated till the middle of August. And about 25,000 of people were evacuated from 107 villages in Belarus. Moreover, more than 60 thousand of horned cattle and other animals were taken out.
In the next period after the accident, the damaged ecosystems are being recovered during tens of years. And these rehabilitation processes are not less interesting and important. Thus, natural vegetative community attacks the left villages and former agricultural areas. Correlation number of some animal species (for example, wild boars) is changing. The Chornobyl catastrophe demonstrated that large-scale release of radionuclides into the environment could have the most serious consequences for biota, including ecosystem level dysfunctions.
The studies conducted within the Chornobyl Exclusion Zone showed that animals and plants’ exposure doses that formed under conditions of such large-scale radiation accidents can be 10 to 300 times more than those of people. Such correlation of doses absorbed by people and other natural objects demands special attention to not only radiation protection of public, but also the one of plants, animals, and their communities.
Conducting of large-scale radioecology research within the territories radioactively contaminated as a result of the largest accident in the history of nuclear energy allowed obtaining unique information about response of nature on various levels of biological structure – from molecular and cellular one to an ecosystem level – under the conditions of large-scale and extremely heterogeneous radiation contamination of vast territories. Summarization and comprehensive analysis of this information will make it possible to estimate a necessity for developing the regulations restricting radiation impact on biota and formulate the principles they are to be based on.