The scale and severity of the Chernobyl accident with its widespread
radioactive contamination had not been foreseen and took by surprise
most national authorities responsible for emergency preparedness.
No provisions had been made for an accident of such scale and,
though some radiation protection authorities had made criteria
available for intervention in an accident, these were often incomplete
and provided little practical help in the circumstances, so that
very few workable national guidelines or principles were actually
in place. Those responsible for making national decisions were
suddenly faced with an accident for which there were no precedents
upon which to base their decisions. In addition, early in the
course of the accident there was little information available,
and considerable political pressure, partially based on the public
perception of the radiation danger, was being exerted on the decision-makers.
In these circumstances, cautious immediate action was felt necessary,
and measures were introduced that tended to err, sometimes excessively
so, on the side of prudence rather than being driven by informed
scientific and expert judgement.
Within the former Soviet Union
The town of Pripyat was not severely contaminated by the initial
release of radionuclides, but, once the graphite fire started,
it soon became obvious that contamination would make the town
uninhabitable. Late on 26 April it was decided to evacuate the
town, and arrangements for transport and accommodation of the
evacuees were made. The announcement of evacuation was made at
11:00 hr the following day. Evacuation began at 14:00 hr, and
Pripyat was evacuated in about two and one half hours. As measurements
disclosed the extensive pattern of deposition of radionuclides,
and it was possible to make dose assessments, the remainder of
the people in a 30-km zone around the reactor complex were gradually
evacuated, bringing the total evacuees to about 135,000.
Other countermeasures to reduce dose were widely adopted (Ko90).
Decontamination procedures performed by military personnel included
the washing of buildings, cleaning residential areas, removing
contaminated soil, cleaning roads and decontaminating water supplies.
Special attention was paid to schools, hospitals and other buildings
used by large numbers of people. Streets were watered in towns
to suppress dust. However, the effectiveness of these countermeasures
outside the 30-km zone was small. An attempt to reduce thyroid
doses by the administration of stable iodine to block radioactive
uptake by the thyroid was made (Me92), but its success
was doubtful.
The Soviet National Committee on Radiation Protection (NCRP) proposed
a 350-mSv lifetime dose intervention level for the relocation
of population groups (Il87). This value was lower by a
factor of 2 to 3 than that recommended by the International Commission
on Radiological Protection (ICRP) for the same countermeasure.
Nevertheless, this value proposed by the NCRP was strongly criticised
as being a very high level. The situation was further complicated
by the political and social tension in the Soviet Union at that
time. As a result, the NCRP proposal was not adopted by the Supreme
Soviet. Later, a special Commission was established which developed
new recommendations for intervention levels. These recommendations
were based on the levels of ground contamination by the radionuclides
caesium-137, strontium-90 and plutonium239. As has been mentioned
above, large areas were contaminated mainly by caesium-137 and
a ground contamination level by this radionuclide of 1,480 kBq/m2
was used as the intervention criterion for permanent resettlement
of population, and of 555 to 1,480 kBq/m2 for temporary relocation.
People who continued to live in the heavily contaminated areas
were given compensation and offered annual medical examinations
by the government. Residents of less contaminated areas are provided
with medical monitoring. Current decisions on medical actions
are based on annual doses. Compensation is provided for residents
whose annual dose is greater than 1mSv. The use of locally produced
milk and mushrooms is restricted in some of these areas. Relocation
is considered in Russia for annual doses above 5 mSv.
As is mentioned in the section on psychological effects, in Chapter
V, the Soviet authorities did not foresee that their attempts
to compensate those affected by the accident would be misinterpreted
by the recipients and increase their stress, and that the label
of "radiophobia" attributed to these phenomena was not
only incorrect, but was one that alienated the public even more.
Some of these initial approaches have been recognised as being
inappropriate and the authorities are endeavouring to rectify
their attitude to the exposed population.
Outside the former Soviet Union
The progressive spread of contamination at large distances from
the accident site has caused considerable concern in Member countries,
and the reactions of national authorities to this situation have
been extremely varied, ranging from a simple intensification of
the normal environmental monitoring programmes, without adoption
of any specific countermeasures, to compulsory restrictions concerning
the marketing and consumption of foodstuffs. This variety of responses
has been accompanied by significant differences in the timing
and duration of the countermeasures.
In general, the most widespread countermeasures were those which
were not expected to impose, in the short time for which they
were in effect, a significant burden on lifestyles or the economy.
These included advice to wash fresh vegetables and fruit before
consumption, advice not to use rainwater for drinking or cooking,
and programmes of monitoring citizens returning from potentially
contaminated areas. In reality, experience has shown that even
these types of measures had, in some cases, a negative impact
which was not insignificant.
Protective actions having a more significant impact on dietary
habits and imposing a relatively important economic and regulatory
burden included restrictions or prohibitions on the marketing
and consumption of milk, dairy products, fresh leafy vegetables
and some types of meat, as well as the control of the outdoor
grazing of dairy cattle. In some areas, prohibitions were placed
on travel to areas affected by the accident and on the import
of foodstuffs from the Soviet Union and Eastern European countries.
In most Member countries, restrictions were imposed on the import
of foodstuffs from Member as well as non-Member countries.
The range of these reactions can be explained primarily by the
diversity of local situations both in terms of uneven levels of
contamination and in terms of national differences in administrative,
regulatory and public health systems. However, one of the principal
reasons for the variety of situations observed in Member countries
stems from the criteria adopted for the choice and application
of intervention levels for the implementation of protective actions.
In this respect, while the general radiation protection principles
underlying the actions taken in most Member countries following
the accident have been very similar, discrepancies arose in the
assessment of the situation and the adoption and application of
operational protection criteria. These discrepancies were further
enhanced by the overwhelming role played in many cases by non-radiological
factors, such as socio-economic, political and psychological,
in determining the countermeasures.
This situation caused concern and confusion among the public,
perplexities among the experts and difficulties to national authorities,
especially in maintaining their public credibility. This was,
therefore, identified as an area where several lessons should
be learned from the accident and efforts directed towards better
international harmonisation of the scientific bases and co-ordination
of concepts and measures for the protection of the public in case
of emergency.
Nowhere was this problem better illustrated than by the way that
contaminated food was handled. In some countries outside the Soviet
Union the main source of exposure to the general population was
the consumption of contaminated food. Mechanisms to handle locally
produced as well as imported contaminated food had to be put in
place within a few weeks of the accident. National authorities
were in an unenviable position. They had to act quickly and cautiously
to introduce measures to protect the "purity" of the
public food supply and, what is more, they had to be seen to be
effective in so doing. This inevitably led to some decisions which
even at the time appeared to be over-reactions and not scientifically
justified. In addition, dissenting opinions among experts added
to the difficulties of the decision-makers.
Some countries without nuclear power programmes and whose own
food was not contaminated, argued that they did not need to import
any "tainted" food and refused any food containing any
radionuclides whatsoever. This extreme and impracticable measure
might well have been regarded as an example of how well the authorities
of those countries were protecting the health of their population.
Sometimes this attitude appeared to promote a neighbourly rivalry
between countries to see which could set the more stringent standards
for food contamination, as though, by so doing, their own citizens
were more protected. The result was that often slightly contaminated
food was destroyed or refused importation to avoid only trivial
doses.
In 1986, the EC imposed a ban on the importation of food containing
more than 370 Bq/kg of radiocaesium for milk products and 600
Bq/kg for any other food, regardless of the quantity consumed
in the average European diet. Thus, food items with a trivial
consumption (and dose), such as spices, were treated the same
as items of high consumption such as vegetables. However, these
values were later relaxed for some food items in order to remove
inconsistent treatment of food groups.
In some special circumstances, decisions had to be made based
on the local situation. For example, in some Northern European
communities, reindeer meat is a major component of the diet; due
to the ecological circumstances, these animals tend to concentrate
radiocaesium, which will then expose the populations which depend
on them. Special countermeasures, such as pasturing reindeer in
areas of lower contamination, were introduced in some countries
to avoid this exposure.
The variety of solutions led to confusion and made any international
consensus on Derived Intervention Levels for food extremely difficult
to achieve, and it was only with the WHO/FAO Codex Alimentarius
Meeting in Geneva in 1989 that any agreement was reached on guideline
values for the radioactivity of food moving in international trade (Table 2).
Often the national authorities were not able accurately to predict
the public response to some of their advice and pronouncements.
For example, in some European countries, soon after the accident
the public were advised to wash leafy vegetables. The national
authority felt that this was innocuous advice as most people washed
their vegetables anyway, and they were unprepared for the public
response which was to stop buying these vegetables. This resulted
in significant economic loss to local producers which far outweighed
any potential benefit in terms of radiological health.
In some countries, the public was told that the risks were very
small but, at the same time, were given advice on how to reduce
these low risks. It was very difficult to explain this apparently
contradictory advice, and the national authority came under criticism
from the media (Sj87). Outside the Soviet Union, the initial
confusion led to inconsistent and precipitate actions which, although
understandable, were sometimes ill-advised and unjustified.
However, it should be emphasised that great progress has been
made since this early confusion. As a result of the actions of
the international organisations to harmonise intervention criteria
and the willingness of countries to cooperate in this endeavour,
a firm groundwork for uniform criteria based on accepted radiation
protection principles has been established, so that relative consistency
can hopefully be expected in their implementation in the event
of a possible future nuclear accident.
In summary, the Chernobyl accident took authorities by surprise
as regards extent, duration and contamination at long distance.
As no guidelines were available for such an accident, little information
was available and great political and public pressure to do something
were experienced, overprecautious decisions were often taken in
and outside the Soviet Union. The psychological impact of some
official decisions on the public were not predicted and variable
interpretations or even misinterpretations of ICRP recommendations,
especially for intervention levels for food, led to inconsistent
decisions and advice. These added to public confusion and provoked
mistrust and unnecessary economic losses. However, there were
exceptions and very soon international efforts started to harmonise
criteria and approaches to emergency management.
Chapter III
REACTIONS OF NATIONAL AUTHORITIES
FOODS FOR GENERAL CONSUMPTION
Radionuclide Level (Bq/kg)
americium-241, plutonium-239
strontium-90
iodine-131, caesium-134, caesium-137
10
100
1,000
INFANT FOODS AND MILK
americium-241, plutonium-239
iodine-131, strontium-90
caesium-134, caesium-137
1
100
1,000
It should be remembered that these guideline values were developed
to facilitate international trade in food, and should be regarded
as levels "below regulatory concern". Levels above these
do not necessarily constitute a health hazard, and if found, the
competent national authority should review what action should
be taken.
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