Chapter I. THE SITE AND ACCIDENT SEQUENCE
The RBMK-1000 reactor
Events leading to the accident
The graphite fire
Chapter II. THE RELEASE, DISPERSION AND DEPOSITION OF
The source term
Chemical and physical forms
Dispersion and deposition
Within the former Soviet Union
Outside the former Soviet Union
Chapter III. REACTIONS OF NATIONAL AUTHORITIES
Within the former Soviet Union
Outside the former Soviet Union
Chapter IV. DOSE ESTIMATES
The evacuees from the 30-km zone
Doses to the thyroid gland
People living in the contaminated areas
Doses to the thyroid gland
Populations outside the former Soviet Union
Chapter V. HEALTH IMPACT
Acute health effects
Late health effects
Other late health effects
Within the former Soviet Union
Outside the former Soviet Union
Chapter VI. AGRICULTURAL AND ENVIRONMENTAL IMPACTS
Within the former Soviet Union
Chapter VII. POTENTIAL RESIDUAL RISKS
Radioactive waste storage sites
Chapter VIII. LESSONS LEARNED
Scientific and technical aspects
EXPLANATION OF TERMS
LIST OF ACRONYMS
As ionising radiation passes through the body, it interacts with
the tissues transfering energy to cellular and other constituents
by ionisation of their atoms. This phenomenon has been extensively
studied in the critical genetic material, DNA, which controls
the functions of the cells. If the damage to DNA is slight and
the rate of damage production is not rapid, i.e. at low dose rate,
the cell may be able to repair most of the damage. If the damage
is irreparable and severe enough to interfere with cellular function,
the cell may die either immediately or after several divisions.
At low doses, cell death can be accommodated by the normal mechanisms
that regulate cellular regeneration. However, at high doses and
dose rates, repair and regeneration may be inadequate, so that
a large number of cells may be destroyed leading to impaired organ
function. This rapid, uncompensatable cell death at high doses
leads to early deleterious radiation effects which become evident
within days or weeks of exposure, and are known as "deterministic
effects". These deterministic effects can be life-threatening
in the short term if the dose is high enough, and were responsible
for most of the early deaths in the Chernobyl accident.
Lower doses and dose rates do not produce these acute early effects,
because the available cellular repair mechanisms are able to compensate
for the damage. However, this repair may be incomplete or defective,
in which case the cell may be altered so that it may develop into
a cancerous cell, perhaps many years into the future, or its transformation
may lead to hereditable defects in the long term. These late effects,
cancer induction and hereditary defects, are known as "stochastic
effects" and are those effects whose frequency, not severity,
is dose dependent. Moreover, they are not radiation-specific and,
therefore, cannot be directly attributed to a given radiation
For this reason, low dose health effects in humans cannot be measured
and, therefore, risk projections of the future health impact of
low-dose ionising radiation exposure have to be extrapolated from
measured high-dose effects. The assumption was made that no dose
of ionising radiation was without potential harm and that the
frequency of stochastic effects at low doses would be proportional
to that occurring at high doses. This prudent assumption was adopted
to assist in the planning of radiation protection provisions when
considering the introduction of practices involving ionising radiations.
The ICRP has estimated the risk of fatal cancer to the general
population from whole-body exposure to be 5 per cent per sievert
The health impact of the Chernobyl accident can be classified
in terms of acute health effects ("deterministic effects")
and of late health effects ("stochastic effects"); moreover
there are also psychological effects which can influence health.
Acute health effects
All the acute deterministic health effects occurred among the
personnel of the plant, or in those persons brought in for fire
fighting and immediate clean-up operations.
Two deaths were immediately associated with the accident: one
person killed by the explosion and another who suffered a coronary
thrombosis. A third person died early the morning of the accident
from thermal burns. Twenty-eight other persons died later in the
treatment centres, bringing the total to 31 deaths in the first
weeks after the accident (UN88).
All symptomatic exposed persons from the site were placed in hospitals.
Of the total of 499 persons admitted for observation, 237 of these
were initially diagnosed as suffering from acute radiation syndrome
and most of these were hospitalised in the first 24 hours. The
severity and rapidity of onset of their symptoms depended on their
dose. The initial early signs and symptoms of radiation sickness
from high doses included diarrhoea, vomiting, fever and erythema.
Over 200 patients were placed in regional hospitals and specialised
centres in the first 24 hours. Patients were allocated to four
categories of radiation sickness severity according to their symptoms,
signs and dose estimates. The differential white blood cell count
showed reduced circulating lymphocytes (lymphocytopenia) which
was the initial indicator of the severity of the exposure and
became evident in the first 24-36 hours for those most severely
No members of the general public received such high whole-body
doses as to induce Acute Radiation Syndrome (IA86). This
was confirmed in Belarus, where, between May and June 1986, 11,600
people were investigated without the discovery of any cases of
acute radiation sickness.
In the highest exposure group (6-16 Gy), the first reaction was
usually vomiting, occurring within 15-30 minutes of exposure.
These patients were desperately ill; fever and intoxication as
well as diarrhoea and vomiting, were prominent features. Mucous
membranes were severely affected, becoming swollen, dry and ulcerated,
making breathing and swallowing extremely painful and difficult.
Extensive burns both thermal and due to beta radiation often complicated
the illness. Within the first two weeks white blood cells and
platelets fell dramatically, indicating a very high dose which
had compromised the production of blood cells in the bone marrow,
making it virtually impossible for the patients to fight infection
or to retain the natural clotting activity of the blood. Almost
all the patients with such high doses died (20 of 21), in spite
of the intensive specialised medical treatment provided.
At lower exposures, the symptoms, signs and laboratory findings
improved. Vomiting began later, platelet and white cell counts
did not drop so precipitously and the fever and toxaemia were
less pronounced. Beta radiation burns to the skin were a major
complicating factor and mucous membrane damage was difficult to
treat, but survival improved markedly at lower doses, so that
no early deaths were noted in the less than 1-2 Gy exposure group
Table 6. Outcome of radiation exposure
among persons hospitalised for acute radiation syndrome.
|Number of patients
|6 - 16|
4 - 6
2 - 4
less than 2
There is a large range of medical treatments that can be attempted
to mitigate the acute radiation syndrome. All these procedures
were applied to the persons hospitalised with varying degrees
of success. The hospital treatment following the accident included
replacement therapy with blood constituents, fluids and electrolytes;
antibiotics; antifungal agents; barrier nursing and bone marrow
The treatment of the depression of bone-marrow function encountered
after the accident was largely supportive. Special hygienic measures
were taken; patients' clothes were changed at least twice a day
and aseptic techniques used. Those patients who received doses
above 2 Gy were given anti-fungal agents after the second week.
Antibiotics and gamma globulin were also administered.
Bone-marrow transplantation was undertaken in 13 patients who
were judged to have irreversible bone marrow damage after doses
greater than 4 Gy. All but two of these patients died, some before
the transfused marrow had had a chance to "take", but
others had short-term takes. It was concluded that, even after
very high radiation doses, the bone marrow may well not be completely
destroyed and may recover at least some function at a later stage.
It is this recovery which may lead to later rejection of the transplanted
marrow through a "Host versus Graft" reaction. The physicians
responsible for treating the victims of the accident concluded
that bone marrow transplantation should play a very limited role
Burns, both thermal and from beta radiation, were treated with
surgical excision of tissue that was not viable, and any fluid
and electrolyte loss was compensated for by the parenteral feeding
set up to treat the gastro-intestinal syndrome which is a prominent
feature of acute radiation sickness. The oro-pharyngeal syndrome
of mucosal destruction, oedema and the absence of lubrication
caused by radiation damage to the mucosa of the mouth and pharynx
was extremely difficult to treat, and severely impaired swallowing
The organisational aspects of treating large numbers of very ill
patients also presented significant problems. Intensive nursing
care and monitoring had to be provided 24 hours a day in small
units. Personnel had to be taught new techniques of care and patient
handling, and a large number of diagnostic samples had to be examined.
The logistic requirements of medical handling needed to be well-established
before any therapeutic programme could be run efficiently.
Late health effects
There have been many reports of an increase in the incidence of
some diseases as a result of the Chernobyl accident. In fact,
the accident has, according to present knowledge, given rise to
an increase in the incidence of thyroid cancers. Also, it has
had negative psychological consequences. As far as other diseases
are concerned, the scientific community has not been able to relate
those to the effects of ionising radiation. However, large research
projects have been conducted and are under way to further study
the matter. For example, the WHO (WH95) established the
International Programme on the Health Effects of the Chernobyl
Accident (IPHECA). This programme initially concentrated on pilot
projects involving leukaemia, thyroid diseases, oral health in
Belarus, mental health in children irradiated before birth and
the development of epidemiological registries. The pilot phase
came to an end in 1994 and, as a result of the findings, efforts
are underway to develop long-term permanent programmes involving
thyroid diseases, the accident recovery workers, dose reconstruction
and guidance to the public in the event of an accident. It is
expected that these new projects will provide further insight
into any future health effects.
An estimate (An88) of the total lifetime cancers which
could be expected in Europe as a result of the accident suggested
an increase of about 0.01 per cent above their natural incidence.
Another assessment placed the increase in cancer incidence at
0.004 per cent in the Northern hemisphere, a lower percentage
increase due probably to including the large population of the
whole hemisphere (Pa89). These predictions are remarkably
similar and support the view that the average doses to the general
population of the Northern hemisphere were so low that only fractions
of a percent increases in cancer incidence could be expected in
this population (Pe88, Re87). Large parts of the
Northern hemisphere, such as North America (Hu88, Br88),
Asia and Siberia, were not significantly contaminated and doses
were inconsequential. Therefore, the following sections focus
on the late health effects in the population of the contaminated
regions of the former Soviet Union.
In the International Chernobyl Project organised by the IAEA
(IA91), field studies were undertaken in the latter half
of 1990 on the permanent residents of the rural settlements with
a surface caesium contamination of greater than 555 kBq/m2, and
on control settlements of 2,000 to 50,000 persons, using an age
matched study design. Seven contaminated and six control settlements
were chosen by the medical team of the Chernobyl Project. Since
all persons could not be examined, representative samples were
taken from various age groups. In all, 1,356 people were examined,
and the aim was to examine about 250 from each of the larger settlements.
Three medical teams each spent two weeks conducting medical examinations
to provide the data for these assessments.
The medical examinations were quite comprehensive, and the general
conclusions reached were that there were no health abnormalities
which could be attributed to radiation exposure, but that there
were significant non-radiation related health disorders which
were similar in both contaminated and control settlements. The
accident had had substantial negative psychological consequences
which were compounded by the socio-economic and political changes
occurring in the former Soviet Union. The official data provided
to the medical teams was incomplete and difficult to evaluate,
and were not detailed enough to exclude or confirm the possibility
of an increase in the incidence of some tumour types. On this
subject, it was suggested in 1991 that the incidence of cancer
in Ukraine showed no large increase even in the most contaminated
The International Chernobyl Project Report (IA91) suggested
that the reported high thyroid doses in some children were such
that there could be a statistically detectable increase in the
incidence of future thyroid tumours. The Chernobyl Project team
finally concluded that, on the basis of the doses estimated by
the team and the currently accepted radiation risk estimates,
future increases over the natural incidence of cancer or hereditary
defects would be difficult if not impossible to discern, even
with very large and well-designed long-term epidemiological studies.
However, it should be remembered that this health survey took
place four years after the accident, before any increase in cancer
incidence might be expected and reflects the status of the people
examined in a few months of 1990. The sample size was also criticised
as being too small.
Nevertheless, the dose estimates generally accepted indicate that,
with the exception of thyroid disease, it is unlikely that the
exposure would lead to discernible radiation effects in the general
population. Many predictions of the future impact of the accident
on the health of populations have been made, all of which, apart
from thyroid disease, indicate that the overall effect will be
small when compared with the natural incidence and therefore not
expected to be discernible (An88, Be87, Hu87, Mo87,
Early in the development of the Chernobyl accident, it became
obvious that the radioiodines were contributing significant thyroid
doses (Il90), especially to children, and the then Soviet
authorities made every effort not only to minimise doses, but
also to record the thyroid doses as accurately as possible. The
results of these measurements and dose reconstruction assessments
indicated that some groups in the population received high doses
to their thyroids, and that an increase in thyroid abnormalities,
including cancer, was a very real possibility in the future. This
was particularly true for children in the contaminated regions
in Belarus, northern Ukraine and the Bryansk and Kaluga regions
of the Russian Federation. These were not inconsequential thyroid
doses and, as early as 1986, it was predicted by experts from
the Soviet Union that the thyroid would be the target organ most
likely to show evidence of radiation effects, especially an increased
incidence of benign and malignant tumours.
It was known from previous studies of largely external irradiation
of the thyroid that an increase in thyroid tumours tended to appear
six to eight years following irradiation, and continue for more
than twenty years after exposure, particularly in children. What
was not expected was that thyroid abnormalities would already
become detectable about four years after the accident. At the
same time, the current conventional wisdom was that internal radioiodine
exposure was less carcinogenic than external irradiation of the
thyroid. It was estimated that the incidence of thyroid cancers
in children, defined as those diagnosed between the ages of 0
and 14, might increase by about 5 per cent, and in adults by about
0.9 per cent over the next 30 years. As will be seen, a substantial
increase has already been detected in the more contaminated regions.
A determined effort was made to estimate doses, record the data,
initiate medical examinations and follow the cohorts already identified
as being most at risk.
In Ukraine, more than 150,000 examinations were conducted by special
dosimetric teams, and a realistic estimate of the collective thyroid
dose of 64,000 person-Sv has been made, leading to a projection
of 300 additional thyroid cancers (Li93a). In the contaminated
regions of Russia, namely Bryansk, Tula and Orel, it was predicted
that an excess thyroid cancer total of 349 would appear in a population
of 4.3 million (Zv93). This represents an increase of 3
to 6 per cent above the spontaneous rate.
A programme to monitor the thyroid status of exposed children
in Belarus was set up in Minsk in May/June 1986. The highest doses
were received by the evacuated inhabitants of the Hoiniki rayon
(district) in the Gomel oblast. In the course of this study, it
was noted that the numbers of thyroid cancers in children were
increasing in some areas. For Belarus as a whole (WH90, Ka92,
Wi94), there has been a significantly increasing trend in
childhood thyroid cancer incidence since 1990 (Pa94). It
was also noted that this increase is confined to regions in the
Gomel and Brest oblasts, and no significant increase has been
noted in the Mogilev, Minsk or Vitebsk areas where the radioactive
iodine contamination is assessed to have been lower. Over 50 per
cent of all the cases are from the Gomel oblast.
For the eight years prior to 1986, only five cases of childhood
thyroid cancer were seen in Minsk, which is the main Belarussian
centre for thyroid cancer diagnosis and treatment on children
(De94). From 1986 to 1989, 2 to 6 cases of thyroid cancer
in children were seen annually in Minsk. In 1990, the number jumped
to 29, to 55 in 1991, then to 67 in 1992. By the end of 1994 the
total had reached over 300 in Belarus. Nearly 50 per cent of the
early (1992) thyroid cancers appeared in children who were aged
between one and four years at the time of the accident.
The histology of the cancers has shown that nearly all were papillary
carcinomata (Ni94) and that they were particularly aggressive,
often with prominent local invasion and distant metastases, usually
to the lungs. This has made the treatment of these children less
successful than expected, whether undertaken in Minsk or in specialised
centres in Europe. In all, about 150,000 children in Belarus had
thyroid uptake measurements following the accident. Other data
from Ukraine and Russia show a similar, but not as pronounced,
increase in the incidence of childhood thyroid cancer since 1987.
The increase in Belarus was confirmed by the final report of an
EC Expert Panel (EC93) convened in 1992 to investigate
the reported increase. In 1992 the incidence of childhood thyroid
cancer in Belarus as a whole was estimated to be 2.77 per 100,000,
whereas in the Gomel and Brest oblasts it was 8.8 and 4.76 respectively.
This increased incidence was not confined to children, as a larger
number of adult cases was registered in Belarus and in Ukraine
There is some difficulty in comparing the numbers quoted by the
health authorities of the former Soviet Union with previous incidence
statistics, as previous data collection was not sufficiently rigorous.
However, in Belarus all cases of childhood thyroid cancer have
been confirmed since 1986 by international review of the histology,
and, because of more rigid criteria for data collection, reliance
can be placed on accuracy and completeness. An attempt to review
incidence estimates was made in the above-mentioned EC Report
(EC93). These experts confirmed that the incidence of childhood
thyroid cancer (0-14 y) prior to the accident in Belarus (between
0 and 0.14/100,000/y) was similar to that reported by other cancer
registries. This indicates that the data collection in Belarus
was adequate. They noted that it jumped to 2.25/100,000/y in 1991,
about a twenty-fold increase.
When this increase was first reported, it was very quickly pointed
out (Be92) that any medical surveillance programme introduced
would apparently increase the incidence by revealing occult disease
and rectifying misdiagnoses. While this may account for some of
the increase (Ro92), it cannot possibly be the sole cause,
as the increase is so large and many of the children presented
not with occult disease, but with clinical evidence of thyroid
and/or metastatic disease. In fact, only 12 per cent of the childhood
thyroid cancers were discovered by ultrasound screening alone
in Belarus (WH95). In addition, subsequent examination
by serial section of the thyroids of persons coming to autopsy
in Belarus have confirmed that the number of occult thyroid cancers
is similar to that found in other studies (Fu93) and showed
none of the aggressive characteristics found in the childhood
cancers presenting in life (Fu92).
The most recent published rates of childhood thyroid cancer (St95)
show unequivocal increases as seen in Table 7. At the time of
writing three children have died of their disease.
Table 7. Number of cases and cases
per million of childhood thyroid cancer (St95)
||1981 - 85
||1986 - 90
It can be concluded that there is a real, and large, increase
in the incidence of childhood thyroid cancer in Belarus and Ukraine
which is likely to be related to the Chernobyl accident. This
is suggested by features of the disease, which differ somewhat
from the so-called natural occurrence, as well as by its temporal
and geographic distribution.
As far as other thyroid disorders are concerned, no difference
in Russia was detected by ultrasound examination, in the percentage
incidence of cysts, nodules or autoimmune thyroiditis in the contaminated
versus the uncontaminated areas (Ts94). Following the accident,
children in the Ukrainian contaminated regions exhibited a transient
dose-dependent increase in serum thyroxine level, without overt
clinical thyrotoxicosis, which returned to normal within 12 to
18 months (Ni94). This was most marked in the youngest
children. This finding cannot be regarded as an adverse health
effect, as no abnormality was permanent. However, it may be a
pointer to future thyroid disease, especially when it may be associated
with mild regional dietary iodine deficiency, and indicates the
need for continued monitoring.
The majority of the estimates indicate that the overall health
impact from these thyroid disorders will be extremely small and
not detectable when averaged over the population potentially at
risk. This viewpoint is widely held by the competent risk assessors
who have examined the potential effects of the accident.
Other late health effects
From data in the Russian National Medical Dosimetric Registry
(RNMDR), the reported incidence of all types of disease has risen
between 1989 and 1992 (Iv94). There has also been a reported
increase in malignant disease which might be due to better surveillance
and/or radiation exposure. The crude mortality rate of the liquidators
from all causes in the Russian Federation has increased from 5
per 1,000 in 1991 to 7 per 1,000 in 1992. The crude death rate
from respiratory cancer is reported to have increased significantly
between 1990 and 1991, and for all malignant neoplasms between
1991 and 1992. It is not clear what influence smoking has had
on these data, and the overall significance of these findings
will need to be established by further surveillance, especially
when there are distinct regional variations in the crude death
rate and the mortality rates from lung, breast and intestinal
cancer are rising in the general population of the Russian Federation.
From the dosimetric data in the RNMDR (Iv94), a predicted
excess 670 cancer deaths may occur in the exposed groups covered
by the Registry, peaking in about 25 years. This is about 3.4
per cent of the expected cancer deaths from other causes. Data
from the other national dose registries is not readily available
in the published literature.
In view of the difficulties associated with these Registry data,
such as the dose estimates, the influence of such confounding
factors as smoking, the difficulty in follow-up, the possible
increase in some diseases in the general population and also the
short time since the accident, it is not possible to draw any
firm conclusions from these data at this time. The only inference
that can be made is that these groups are the most exposed and
that, if any radiation effects are to be seen, they will occur
in selected cohorts within these registries, which will require
long-term future surveillance.
A predicted increase of genetic effects in the next two generations
was 0.015 per cent of the spontaneous rate, and the estimated
lifetime excess percentage of all cancers as a result of living
in the strict control zones was 0.5 per cent, provided that a
lifetime dose limit of 350 mSv was not exceeded (Il90).
Childhood leukemia incidence has not changed in the decade since
the accident. There is no significant change in the level of leukemia
and related diseases in the contaminated (more than 555 kBq/m2)
and noncontaminated territories of the three states (WH95).
Other attempts through epidemiological studies have failed to
establish a link between radiation exposure from the Chernobyl
accident and the incidence of leukemia and other abnormalities.
No epidemiological evidence of an increase in childhood leukemia
around Chernobyl (Iv93), in Sweden (Hj94) or the
rest of Europe (Pa92, Wi94) has been established. However,
it may be prudent to withold final judgement on this issue for
a few more years.
Various reports (Pa93, Sc93, Se95, St93, Ve93) have been
published on the incidence of chromosome aberrations among people
exposed both in the contaminated regions and in Europe. Some of
these have shown little or no increase, while others have. This
may reflect the wide variation in dose. However, there is a trend
for the incidence of chromosome aberrations to return to normal
with the passage of time. Other studies have not shown evidence
of lymphocytic chromosome damage (Br92).
In East Germany one study found no rise in foetal chromosome aberrations
between May and December 1986. Chromosome aberrations are to be
expected in any exposed population, and should be regarded as
biological evidence of that exposure, rather than an adverse health
Another study in Germany suggesting a link between Down's syndrome
(Trisomy 21) and the Chernobyl accident has been severely criticised
and cannot be accepted at face value because of the absence of
control for confounding factors (Sp91), and it was not
confirmed by more extensive studies (Li93). Another study
in Finland (Ha92) showed no association of the incidence
of Trisomy 21 with radiation exposure from Chernobyl.
There are no clear trends in data for birth anomalies in Belarus
or Ukraine (Li93, Bo94). Two epidemiological studies in
Norway concluded that no serious gross changes as to pregnancy
outcome were observed (Ir91), and that no birth defects
known to be associated with radiation exposure were detected (Li92).
In Austria, no significant changes in the incidence of birth defects
or spontaneous abortion rates which could be attributed to the
Chernobyl accident were detected (Ha92a).
A review by the International Agency for Research on Cancer (IARC)
showed no consistent evidence of a detrimental physical effect
of the Chernobyl accident on congenital abnormalities or pregnancy
outcomes (Li93, EG88). No reliable data h). No reliable data have shown any
significant association between adverse pregnancy outcome or birth
anomalies even in the most contaminated regions and the doses
indicate that none would be expected.
There have been reports that have suggested that radiation exposure
as a result of the accident resulted in altered immune reactions.
While immune suppression at high whole-body doses is known to
be inevitable and severe, at the low doses experienced by the
general population it is expected that any detected alterations
will be minor and corrected naturally without any medical consequences.
These minor changes may be indicative of radiation exposure, but
their mild transitory nature is unlikely to lead to permanent
damage to the immune system. All immunological tests of radiation
exposure are in their infancy, but tests such as stimulated immunoglobulin
production by lymphocytes hold promise for the future as a means
of assessing doses below one Gy (De90).
The severity of the psychological effects of the Chernobyl accident
appears to be related to the public's growing mistrust of officialdom,
politicians and government, especially in the field of nuclear
power. Public scepticism towards authority is reinforced by its
difficulty in understanding radiation and its effects, as well
as the inability of the experts to present the issues in a way
that is comprehensible. The impression that an unseen, unknowable,
polluting hazard has been imposed upon them by the authorities
against their will, fosters a feeling of outrage.
Public outrage is magnified by the concept that their existing
or future descendants are also at risk from this radiation pollution.
This widespread public attitude was not confined to one country,
and largely determined the initial public response outside the
Soviet Union. The public distrust was increased by the fact that
the accident that they had been told could not happen, did happen,
and it induced anxiety and stress in people not only in the contaminated
areas but, to a lesser extent, all over the world.
While stress and anxiety cannot be regarded as direct physical
adverse health effects of irradiation, their influence on the
well-being of people who were exposed or thought that they might
have been, may well have a significant impact on the exposed population.
Several surveys have shown that the intensity of the anxiety and
stress are directly related to the presence of contamination.
It should also be remembered that the stress induced by the accident
was in addition to that produced in the general population by
the severe economic and social hardship caused by the break-up
of the Soviet Union.
Within the former Soviet Union
Within the Soviet Union additional factors came into play to influence
the public reaction. It should be remembered that this accident
occurred during the initial period of "glasnost" and
"perestroika". After nearly seventy years of repression,
the ordinary people in the Soviet Union were beginning openly
to express all the dissatisfaction and frustration that they had
been harbouring. Distrust and hatred of the central government
and the Communist system could be expressed for the first time
without too much fear of reprisal. In addition, nationalism was
not repressed. The Chernobyl accident appeared to epitomise everything
that was wrong with the old system, such as secrecy, witholding
information and a heavy-handed authoritarian approach. Opposition
to Chernobyl came to symbolise not only anti-nuclear and anti-communist
sentiment but also was associated with an upsurge in nationalism.
The distrust of officialdom was so great that even scientists
from the central government were not believed, and more reliance
was placed on local "experts" who often had very little
expertise in radiation and its effects. The then Soviet Government
recognised this problem quickly, and tried to counteract the trend
by inviting foreign experts to visit the contaminated areas, assess
the problems, meet with local specialists and publicise their
views in open meetings and on television. These visits appeared
to have a positive effect, at least initially, in allaying the
fears of the public. In the contaminated Republics, anxiety and
stress were much more prevalent and were not just confined to
the more heavily contaminated regions (WH90a). Several
surveys conducted by Soviet (Al89) and other researchers
(Du94) have shown that the anxiety induced by the accident
has spread far beyond the more heavily contaminated regions.
During this period there was severe economic hardship which added
to the social unrest and reinforced opposition to the official
system of government. Anti-nuclear demonstrations were commonplace
in the larger cities in Belarus (Gomel and Minsk), and Ukraine
(Kiev and Lvov) in the years following the accident (Co92).
The dismissive attitude of some Soviet scientists and government
officials in describing the public reaction as "radiophobic"
tended to alienate the public even further by implying some sort
of mental illness or reaction which was irrational and abnormal.
It also served as a convenient catch-all diagnosis which suggested
that the public was somehow at fault, and the authorities were
unable to do anything about its manifestations.
The concern of people for their own health is only overshadowed
by their concern for the health of their children and grandchildren.
Major and minor health problems are attributed to radiation exposure
no matter what their origin, and the impact that the accident
has had on their daily lives has added to the stress. Whole communities
are facing or have faced evacuation or relocation. There are still
widespread restrictions on daily life affecting schooling, work,
diet and recreation.
The accident has caused disruption of social networks and traditional
ways of life. As most inhabitants of the contaminated settlements
are native to the area and often have lived there all their lives,
relocation has in many cases, destroyed the existing family and
community social networks, transferring groups to new areas where
they may well be resented or even ostracised. In spite of these
drawbacks, about 70 per cent of the people living in contaminated
areas wished to be relocated (IA91). This may well be influenced
by the economic incentives and improved living standards that
result from relocation by the government.
There are two additional circumstances and events which have tended
to increase the psychological impact of the accident, the first
of which was an initiative specifically designed to alleviate
these effects in Ukraine. This was the introduction of the compensation
law in Ukraine in 1991. Some three million Ukrainians were affected
in some way by the post-accident management introduced, upon which
approximately one sixth of the total national budget was spent
(Du94). Different surveys have shown a general feeling
of anxiety in all sectors of the population, but it was particularly
acute among those who had been relocated. People were fearful
of what the future might bring for themselves and their offspring,
and were concerned about their lack of control over their own
The problem is that the system of compensation may well have exaggerated
these fears by placing the recipients into the category of victims.
This tended to segregate them socially and increased the resentment
of the native population into whose social system these "victims"
had been injected without consultation. This had the effect on
the evacuees of increasing stress, often leading to withdrawal,
apathy and despair. Locally, this compensation was often referred
as a "coffin subsidy"! It is interesting to note that
the 800 or so mostly elderly people who have returned to their
contaminated homes in the evacuated zones, and hence receive no
compensation, appear to be less stressed and anxious, in spite
of worse living conditions, than those who were relocated. It
should be pointed out that compensation and assistance are not
harmful in themselves, provided that care is taken not to induce
an attitude of dependence and resignation in the recipients.
The second factor which served to augment the psychological impact
of the accident was the acceptance by physicians and the public
of the disease entity known as "vegetative dystonia".
This diagnosis is characterised by vague symptoms and no definitive
diagnostic tests. At any one time, up to 1,000 children were hospitalised
in Kiev, often for weeks, for treatment of this "disease"
(St92). The diagnosis of vegetative dystonia appears to
be tailor-made for the post-accident situation, assigned by parents
and doctors to account for childhood complaints and accepted by
adults as an explanation for vague symptoms.
There is great pressure on the physicians to respond to their
patients' needs in terms of arriving at an acceptable diagnosis,
and "Vegetative Dystonia" is very convenient as it will
fit any array of symptoms. Such a diagnosis not only justifies
the patients' complaints by placing the blame for this "disease"
on radiation exposure, it also exonerates the patient from any
responsibility, which is placed squarely on the shoulders of those
responsible for the exposure - the Government. When the need for
extended hospitalisation is added, the justification to accept
this as a real disease is enhanced. It can be understood why there
is an epidemic of this diagnosis in the contaminated areas.
Outside the former Soviet Union
Psychological effects in other countries were minimal compared
with those within the former Soviet Union, and were generally
exhibited more as concerned social reactions rather than psychosomatic
symptoms. In the contaminated regions of the former Soviet Union,
many people were convinced that they were suffering from radiation
induced disease, whereas in the rest of the world, where contamination
was much less, news of the accident appeared to reinforce anti-nuclear
perceptions in the general population. This was evidenced, for
example, by the demonstrations on 7 June 1986 demanding the decommissioning
of all nuclear power plants in the Federal Republic of Germany
(Ze86). While in France public support for nuclear power
expansion dropped since the accident, 63 per cent of the population
felt that French nuclear power reactors operated efficiently (Ch90).
The minimal impact of the Chernobyl accident on French public
opinion was probably due to the fact that about 75 per cent of
their electrical power is derived from nuclear stations, and in
addition, France was one of the least contaminated European countries.
The Swedish public response has been well-documented (Dr93,
Sj87). In the survey, the question was asked: "With
the experience that we now have, do you think it was good or bad
for the country to invest in Nuclear Energy?" Those that
responded "bad" jumped from 25 per cent before, to 47
per cent after Chernobyl. The accident probably doubled the number
of people who admitted negative attitudes towards nuclear power
(Sj87). This change was most marked among women, who, it
was felt, regarded nuclear power as an environmental problem,
whereas men regarded it as a technical problem which could be
solved. Media criticism of the radiation protection authorities
in that country became more common, with the charge that the official
pronouncements on the one hand said that the risk in Sweden was
negligible, and yet on the other, gave instructions on how it
could be reduced. The concept that a dose, however small, should
be avoided if it could be done easily and cheaply, was not understood.
This sort of reaction was common outside the former Soviet Union,
and while it did not give rise to significant psychosomatic effects,
it tended to enhance public apprehension about the dangers of
nuclear power and foster the public's growing mistrust of official
In addition, public opinion in Europe was very sceptical of the
information released by the Soviet Union. This mistrust was reinforced
further by the fact that the traditional sources of information
to which the public tended to turn in a crisis, the physicians
and teachers, were no better informed and often only repeated
and reinforced the fears that had been expressed to them. Added
to this were the media, who tended to respond to the need to print
"newsworthy" items by publishing some of the more outlandish
claims of so-called radiation effects.
The general public was confused and cynical and responded in predictable
but extreme ways such as seeking induced abortions, postponing
travel and not buying food that might conceivably be contaminated.
Another global concern that was manifested, was the apprehension
over travel to the Soviet Union. Potential travellers sought advice
from national authorities on whether to travel, what precautions
to take and how they could check on their exposure. Many people,
in spite of being reassured that it was safe to travel, cancelled
their trip, just to be on the safe side, exhibiting their lack
of confidence in the advice they received.
As has been seen, governments themselves were not immune from
the influence of these fears and some responded by introducing
measures such as unnecessarily stringent intervention levels for
the control of radionuclides in imported food. Thus, in the world
as a whole, while the individual psychological effects due to
anxiety and stress were probably minimal, the collective perception
and response had a significant economic and social impact. It
became clear that there was a need to inform the public on radiation
effects, to provide clear instructions on the precautions to be
taken so that the public regains some level of personal control,
and for the authorities to recognise the public's need to be involved
in the decisions that affect them.
In summary, it can be stated that:
- Thirty-one people died in the course of the accident or
soon after and another 137 were treated for the acute radiation
- Extensive psychological effects are apparent in the affected
regions of the former Soviet Union, manifested as anxiety and
stress. Severe forms induce a feeling of apathy and despair often
leading to withdrawal. In the rest of the world these individual
effects were minimal.
- In the last decade, there has been a real and significant
increase in childhood and, to a certain extent, adult carcinoma
of the thyroid in contaminated regions of the former Soviet Union
(Wi940) which should be attributed to the Chernobyl accident
until proven otherwise.
- In children, the thyroid cancers are:
- largely papillary and particularly aggressive in nature
often self presenting with local invasion and/or distant metastases,
- more prevalent in children aged 0 to 5 years at the time
of the accident, and in areas assessed to be the more heavily
contaminated with iodine-131,
- apparently characterised by a shorter latent period than
- still increasing.
- There has been no increase in leukemia, congenital abnormalities,
adverse pregnancy outcomes or any other radiation induced disease
in the general population either in the contaminated regions or
in Western Europe, which can be attributed to this exposure. It
is unlikely that surveillance of the general population will reveal
any significant increase in the incidence of cancer.