The consequences of the Chernobyl accident

1
The consequences of the Chernobyl accident

• Maryna Karavai,
• FRI
• 26th April, 2006
• Stockholm

2
Introduction

• Twenty years after the Chernobyl disaster, the
  need for continued study of its far-reaching
  consequences remains as great as ever.
• Twenty years later, several million people (by
  various estimates, from 5 to 8 million) still
  reside in areas that will remain highly
  contaminated by Chernobyls radioactive pollution
  for many years to come. Since the half-life of
  the major radioactive element released,
  caesium-137 (137Cs), is a little over 30 years,
  the radiological and health consequences of this
  nuclear accident will continue to be experienced
  for centuries to come.

3

• This truly global event had its greatest impacts
  on three neighbouring former Soviet republics,
  namely the now independent countries of Ukraine,
  Belarus, and Russia. The impacts, however,
  extended far more widely. More than half of the
  caesium-137 emitted as a result of the explosion
  was carried in the atmosphere to other European
  countries. At least fourteen other countries in
  Europe (Austria, Sweden, Finland, Norway,
  Slovenia, Poland, Romania, Hungary, Switzerland,
  Czech Republic, Italy, Bulgaria, Republic of
  Moldova and Greece) were contaminated by
  radiation levels above the 1 Ci/km2 limit used to
  define areas as contaminated.

4
Where is Chernobyl?

• The Chernobyl power plant is about 7 km from the
  border with Belarus, while about 120 km to the
  south lies Kiev, the capital of Ukraine, with a
  population of about 3 million. The reactor
  complex, which has been inactive since 12
  December 2000, stands by the river Pripyat, which
  joins the Dnieper at the town of Chernobyl, 12 km
  away.

5
The present state of the shelter

• There are evidences that the technical condition
  of the construction do not meet the safety
  requirements. No one knows what exactly is
  happening with the nuclear fuel which still
  remains in the reactor covered with the shelter.
  On the projects to ensure the safety of the
  reactor 440 millions Euro has been spent already.
  The maximum level of the gamma radiation inside
  the installation amounts to 3000 x-ray per hour.

6
Which areas were contaminated by radiation?

• The contaminated territories lie in the north of
  Ukraine, the south and east of Belarus and in the
  western border area between Russia and Belarus.
  International estimates suggest that a total of
  between 125 000 and 146 000 km2 in Belarus,
  Russia and Ukraine are contaminated with
  caesium-137 at levels exceeding 1 curie (Ci) or
  3.7 x 1010 becquerel (Bq) per square kilometre.

7
Which areas were contaminated by radiation?

• At the time of the accident, about 7 million
  people lived in the contaminated territories,
  including 3 million children. About 350 400
  people were resettled or left these areas.
  However, about 5.5 million people, including more
  than a million children, continue to live in the
  contaminated zones.

8
Which areas were contaminated by radiation?

• Most of the contaminated territory lies in
  Belarus, since up to 70 per cent of the total
  fallout was deposited there. Of the total area of
  Belarus, 22 per cent was contaminated with more
  than 1 Ci/km2 caesium-137. At the time of the
  accident, 2.2 million people lived in these
  areas, one fifth of the population of Belarus.
  7.25 per cent of Ukraine's territory was
  contaminated following the accident, and 0.6 per
  cent of the Russian Federation

9
The amounts of radiation released

• During the maximum credible accident at the
  Chernobyl nuclear power station, an estimated 50
  to 250 million Ci of radiation was released.
• Most estimates give the amount as between 3.8 and
  20 per cent. At the time of the accident there
  were 200 tones of uranium in the reactor.

10
What effects did the accident have on plants?

• Currently, the most severe contamination is found
  in typical forest plants such as berries,
  mushrooms, heather, lichens and ferns.
• Opinions differ as to the consequences of the
  contamination for the DNA of plants
• Fourteen years after the disaster, scientists
  from the Friedrich Miescher Institute in Basel
  planted wheat on a field beside the reactor and
  30 km away. After only 10 months, or one
  generation, the plants near the reactor showed a
  mutation rate of 6.63 per mille. On the control
  field, the rate was only 1.03 per mille.

11
What effects did the accident have on animals?

• Among domestic animals and agricultural
  livestock, grazers such as cattle and goats have
  been especially susceptible to bioaccumulation of
  radioactivity, in both meat and milk.
• In the contaminated forest areas, game is still
  severely contaminated, because it feeds on
  contaminated lichens, berries and mushrooms.
  Predators such as the wolf and fox are up to 12
  times more contaminated than the herbivores on
  which they feed.

12
What effects did the accident have on animals?

• In the rivers and lakes of the contaminated
  territories, radiation has concentrated
  particularly in the sediments, with values of up
  to 1 million Bq per cubic metre of sludge
  observed in Belarus, for example.

13
What consequences did the accident have for
waterways?

• In addition to rainfall, it was the rivers -
  particularly the Pripyat and the Dnieper - that
  transported the radiation on their surfaces in
  the first ten days after the accident.
• For Ukraine, however, contamination via river
  water is still a major problem, since most of the
  rivers flow southwards. This is a particular
  threat for the 30 million people who obtain their
  drinking water from the Dnieper basin.

14
Health effects

• Four population groups appear to have experienced
  the most severe health effects
• accident clean-up workers, or liquidators,
  including civilian and the military personnel
  drafted to carry out clean-up activities and
  construct the protective cover for the reactor
• evacuees from dangerously contaminated
  territories inside the 30-km zone around the
  power plant
• residents of the less (but still dangerously)
  contaminated territories and
• children born into the families from all of the
  above three groups.

15
Cancer diseases.

• Today it is clear that the pollution from
  Chernobyl has indeed caused a large-scale
  increase in cancers. In particular, cancers are
  notably more common in populations from the \
  highly contaminated regions and among the
  liquidators (highest radiation exposure) in
  comparison with reference (relatively unexposed)
  groups.
• Sisters Irina and Yelena live in an area of
  Belarus contaminated by the Chernobyl disaster.
  Both have had brain tumours removed and now have
  problems with their thyroid glands.

16
Other examples include

• Between 1990 and 2000, a 40 increase in all
  cancers in Belarus was documented, with higher
  increases (52) in the highly contaminated Gomel
  region than in the less contaminated regions of
  Brest (33) and Mogilev (32).
• In Russia, cancer morbidity in the highly
  contaminated Kaluga and Bryansk regions was
  higher than across the country as a whole. For
  example, in heavily contaminated areas of Bryansk
  region, morbidity was 2.7 times higher than in
  less contaminated territories of the region.
• In contaminated areas of the Zhytomir region of
  Ukraine, the number of adults with cancer
  increased almost threefold between 1986 and 1994,
  from 1.34 to 3.91.

17
Thyroid cancer

• Thyroid cancer increased dramatically in all
  three countries, as expected because of the
  release of large quantities of radioactive iodine
  from the Chernobyl catastrophe. For example,
  incidence in the highly contaminated Bryansk
  region in the period 1988-1998 was double that
  for Russia as a whole, and triple that figure by
  2004. Estimates in excess possibly of 60, 000
  additional cases have been predicted for Ukraine,
  Belarus and the Russian Federation alone.

18
Leukaemia

• Higher rates of acute leukaemia among Belarusian
  liquidators were first observed in 1990-91.
  From 1992, significant increases in the incidence
  of all forms of leukaemia were detectable in the
  adult population of Belarus as a whole. In the
  Ukraine, the frequency of malignant blood cancers
  was significantly higher than for the
  pre-catastrophe period in the four most highly
  contaminated parts of Zhytomyr and Kiev regions,
  both during the first four years and during the
  sixth year after the catastrophe.

19
Non-Cancer illnesses

• The identified changes in the incidence of
  cancerous diseases reported from studies of
  populations exposed to radiation arising from the
  Chernobyl accident are only one aspect of the
  range of health impacts reported. In addition,
  significant increases in non-cancer illnesses
  amongst the exposed populations have also been
  reported although, despite the scale of the
  exposure, relatively very few studies are
  available.

20
Genetic abnormalities Chromosomal aberrations

• Frequency of aberrant cells and chromosomal
  aberrations per 100 lymphocytes in contaminated
  areas of Ukraine and Belarus reached up to three
  times the global average. In Russia, frequency of
  chromosomal aberrations increased 2 to 4-fold in
  inhabitants of territories with contamination
  levels over 3 Ci/km2, while a study of a number
  of Ukrainian residents before and after the
  Chernobyl accident revealed a 6-fold increase in
  frequency of radiation-induced chromosome
  changes, a phenomenon which also seems to be
  carried over to their children.

21
Genetic abnormalities Chromosomal aberrations

• Chromosomal aberrations thought to be
  attributable to Chernobyl have been recorded as
  far away as Austria, Germany and Norway.
• The frequencies of chromosomal aberrations in
  areas of the Ukraine, Belarus and Russia that
  were contaminated by Chernobyl fallout are
  noticeably higher than the global average.
• Nine-year-old Alexandra with her father Vitaly in
  Gomel, Belarus. Alexandra has a birth defect,
  called hydrocephalus. Vitaly has quit his job to
  care for his daughter. The family lives in the
  fall out zone of the Chernobyl disaster.

22
Conclusions

• Clearly the overall body of evidence concerning
  human health impacts of the radiation released by
  the Chernobyl accident is highly diverse and
  complex but of great significance. Many of the
  features of the accident and its consequences,
  such as uncertainty regarding total quantities of
  radionuclides released, uneven distribution of
  radioactivity, concomitant and sequential effects
  of multiple radioisotope exposures, as well as
  limitations in medical monitoring, diagnosing,
  forecasting and treating diseases, make it
  altogether unique, thus rendering many previously
  applied standards and methods inapplicable.
  Complete evaluation of the human health
  consequences of the Chernobyl accident is
  therefore likely to remain an almost impossible
  task, such that the true extent of morbidity and
  mortality resulting may never be fully
  appreciated.